Mata Kuliah : Hortikuiltura 1
Prodi : Agroteknologi
Semester : V (loma)
Pertemuan : 2 (dua)
Hari/jam : Senin, 22 Sept'08 / 10.00-11.45

2. PERANAN HORTIKULTURA DALAM KEHIDUPAN SEHARI-HARI

It is not a home until it’s planted

Pada uraian sebelumnya, telah jelas bahwa hortikultura adalah pengusahaan jenis-jenis tanaman buahan, sayuran, dan tanaman hias. Demikian juga telah dikemukakan bahwa hortikultura merupakan suatu bentuk pengusahaan kebun, namun di dalam kenyataannya hortikultura telah banyak berkembang dan tidak hanya membatasi diri pada areal kebun. Banyak jenis pertanaman hortikultura telah diusahakan pada areal-areal berhektar luasnya, sehingga tidak saja terbatas pada areal kebun di sekitar rumah. Secara sadar ataupun tidak, di dalam kenyataan kehidupan manusia sehari-hari selamanya terlibat dengan hortikultura. Hal ini disebabkan karena produksi hortikultura yang beraneka secara langsung merupakan bahan konsumsi bagi kehidupan, baik dalam pemenuhan kebutuhan jasmaniah maupun rohaniah.

Peranan hortikultura dalam kehidupan, secara umum dapat digambarkan antara lain sebagai berikut :

1. ILMU PENGETAHUAN. Berbagai jenis tanaman hortikultura dapat berfungsi sebagai objek penelitian dalam usaha pengembangan ilmu pengetahuan. Demikian juga sebagai objek yang secara luas merupakan bahan pelajaran bagi para guru, penyuluh pertanian ataupun para profesional maupun amatir yang bergerak di bidang ini. Sebagai objek penelitian, berbagai jenis tanaman hotikultura buah, sayur, dan tanaman hias digunakan antara lain untuk percobaan lapangan menyakut pemuliaan tanaman, pemupukan, pemberantasan hama dan penyakit, masalah proteksi gulma, penerapan konsep pola tanaman dan berbagai hal lainnya. Asian Vegetables Research and Development Centre (AVRDC) di Taiwan, adalah suatu lembaga pusat penelitian berbagai jenis tanaman sayuran . sebagai contoh adanya varietas tomat AVRDC. Di Hawaai dengan Tropical Institute, juga merupakan lembaga dengan fungsi sama. Di Indonesia : Lembaga Penelitian Hortikultura di Cimanggu-Bogor, Malang, Pasar Minggu dan sebabainya.
2. PENGUSAHAANNYA. Banyak negara-negara di dunia yang memanfaatkan jenis-jenis tanman hortikultura sebagai sumber devisa negaranya. Buahan, sayuran maupun tanaman hias, ketiganya berfungsi sama. Sebagai misal : (a) di California, beribu-ribu luas lahan dikelola untuk pengusahaan jeruk. Produksi jeruk kemudian dijual atau diekspor dalam bentuk buah segar ataupun melalui pengolahan yang telah terkenal dengan minuman bermerak dagang “Sunkist-Orange”, (b) di Indonesia pada waktu sebelum perang dunia ke II, juga mengadakan penguhasaan pisang secara besar-besaran yang kemudian diekspor ke luar negeri antara lain ke Malasia dan Australia. (c) di Belanda beratus-ratus areal hektar lahan yang diperuntukkan bagi pembangunan “Green House” yang mana di dalamnya diusahakan berjenis-jenis tanaman hias yang kemudian dieksport ke luar nigeri dalam bentuk “Cut Flower”. Terdapat banyak pula perusahaan yang mengkhususkan diri didalam memproduksi benih tanaman sayuran (kacang-kacangan dan biji-bijian) dan tanaman hias (urbi : tulip) yang kemudian diekspot. (d) di Hawai nenas, pisang dan pepaya merupakan jenis-jenis buahan yang banyak memonopoli luasan areal perkebunan di negara bagian Amerika Serikat ini. Demikian halnya dengan di Taiwán (RRC). Di Indonesia sendiri tersebar berbagai sentra-sentra produksi sayuran, buahan, dan tanman hias (antara lain anggrek) yang diusahalkan secara intensif dengan menggunakan teknologi mutakhir. Hal ini disebabkan karena adanya kesadaran bahwa produksi hortikultura merupakan kebutuhan di dal;am kehidupan sahrí-hari secara menyeluruh. Demikian juga tidak sedikit jumlah pengusaha yang mengkhususkan diri di bidang produksi benih (Nursery) tanaman-tanaman hortikultura, baik sayuran, buahan, maupun tanaman hias.
3. KEBUTUHAN JASMANIAH DAN ROHANIAH. Sebagaimana diketahui bahwa “makanan” pada prinsipnya mempunyai tiga fungsi utama, yaitu : (a) sebagai zat pembangkit tenaga, (b) sebagai zat pembangun, dan (c) sebagai zat pengatur tubuh manusia.

ZAT PEMBANGKIT TENAGA. Produksi Jenis-jenis tanaman secara lansung berfungsi sebagai pembangkit tenaga adalah yang mengandung karbohidrat. Yang tergolong jenis-jenis tanaman hortikultura yang memberikan karbohidrat, antara lain : kentang, pisang, jagung manis, kacang merah, kacang tanah, kacang tunggak, buah nona, sawo, salak, dan advokad.

ZAT PEMBANGUN. Produksi jenis tanaman yang memberikan jumlah protein sebagai zat pembangun bagi tubuh manusia, antara lain : kedele, kecipir, kacang tanah, kacang hijau, dan jagung Manis.

ZAT PENGATUR. Untuk mengatur kondisi tubuh manusia yang menderita sakit, cedera atau luka, agar berada kembali dalam keadaan sehat, diperlukan sejumlah vitamin dan mineral. Untuk itu perlu adanya suplai produksi yang mengandung zat-zat tersebut, antara lain : ubi jalar merah, wortel, jagung kuning, bayam, daun singkong, daun melinjo, daun katuk, advokad, belimbing, dan pisang.

4. OBAT-OBATAN. Produksi kebun yang dapat memberikan sumbangan sebagai bahan baku obat-obatan secara langsung, secara sendiri-sendiri atau tercampur, dan kemudiaan dikelola dalam industri farmasi, banyak diusahakan. Sebagai misal terdapat banyak tanaman kebun berupa rempah-rempah yang kemudian dikelola dalam bentuk jamu tradisional atau dalam bentuk kapsul yang saat ini sudah populer seperti : Zingiber sp, Mayana, Daun tebal (Ambon), lidah buaya (rambut), gardenia, dan daun jarak.
5. SENI. Produksi tanaman hias merupakan sumbangan dalam bidang seni. Unuk program pertanaman atau ”Landschaping” yang mendatangkan rasa keindahan, tentunya digunakan elemen tanaman, disamping elemen batu, pasir, dan lain-lain. Di dalam seni suara, seni lukis, tidak jarang digunakan jenis kembang sebagai objek untuk memberikan kesan halus dan indah. Sebagai contoh di Amerika sering digunakan Roses, Violet, Tulip, dan Berry. Di Jepang : Sakura, di Indonesia : Mawar dan Melati,. Di Prancis : Lelly, di Hawaii : Kembang sepatu dan Kamboja. Demikian halnya dengan seni merangkai bunga (Ikebana di Jepang). Buah, sayur, dan tanaman hias untuk ”janur” kesemuanya merupakan sumbangan bidang hortikultura bagi dunia seni. Salah satu fungsi hortikultura yang memberikan sumbangan yang cukup besar artinya bagi kehidupan manusia, seperti yang terlihat di Amerika yaitu program pengaturan taman dengan menggunakan sususnan tanaman hias dengan panduan warna khusus untuk menenangkan para penderita penyakit gangguan syaraf. Di rumah-rumah sakit, hal ini banyak dilakukan sehingga cara ini lazim dikenal dengan Horticulture Theraphy. Demikian halnya dengan seni pengaturan taman di kampus yang sangat berfungsi mendatangkan suasana indah, relax, dan gembira setelah jenuh dengan kuliah ataupun praktika yang melelahkan jasmaniah mauoun rohaniah. Penataan tempat-tempat rekreasi (recreation park) baik di dalam kota (Jakarta : Taman Impian Jaya Ancol, Taman Ismail Marzuki, Taman Puring; Ambon : Taman Palm samping PDAM dan taman di Australia Cemetary Tantui; Bogor : Bogor Botanical Garden) maupun di luar kota (Cibubur : Taman Bunga Wiladatika; Cibodas : Kebub Raya Cibodas), merupakan contoh nyata sumbangan bidang hortikultura didalam kehidupan sehari-hari, khususnya berhubungan dengan pemenuhan kebutuhan rohaniah (nilai estetika).

C. BENTUK-BENTUK HORTIKULTURA DI INDONESIA

DAN DI AMERIKA SERTA EROPA

Sebagaimana telah dijelaskan bahwa hortikultura merupakan suatu bentuk pertanian yang mengusahakan atau mengelola tanaman kebun (buahan, sayuran dan tanaman hias). Bentuk-bentuk hortikultura yang ditemukan di Indonesia dapat dikelompokan atas tiga bagian, yaitu : (1) bentuk pekarangan (Mixed Garden atau home gardening), (2) kebun khusus buahan, sayuran dan tanaman hias, (3) kebun khusus pembibitan

BENTUK PEKARANGAN

Prof. Ir. Terra (1948) memberikan definisi bahwa pekarangan adalah bidang tanah sekitar rumah yang kebanyakan berpagar keliling dan biasanya ditanami dengan berjenis-jenis tanaman musiman atau tanaman umur panjang untuk keperluan sesehari atau didagangkan.

Definisi atau batasan ini lebih dikembangkan oleh Prof. Ir. Harjono Danoesastro (GAMA) dan Prof .Dr. Ir. Otto Soemarwoto (Untad) sebagai berikut : pekarangan adalah bidang tanah sekitar rumah yang jelas batas-batasnya, ditanami dengan satu, atau berbagai jenis tanaman dan masih mempunyai hubungan hak pemilik dan atau fungsional dengan rumah yang bersangkutan (I). disamping itu ada juga batasan yang dikemukakan oleh Soemarwoto yang menganggap pekarangan sebagai suatu ekosistem, bahwa pekarangan adalah sebidang tanah sekitar rumah yang ditanami bermacam-macam tumbuhan liar yang sebagiannya digunakan oleh penduduk sebagai sayur, obat, atau lain keperluan. Di dalam pekarangan juga dipelihara bermacam-macam hewan yang harus dianggap sebagai bagian integral dari system pekarangan (II).

Dari uraian di atas jelas bahwa berbagai jenis tanaman hortikultura banyak memberikan sumbangan keanekaan tanaman pekarangan.

Pekarangan merupakan suatu bentuk hortikultura atau bentuk pertanian yang di dalam kenyataannya memberikan banyak manfaat bagi kehidupan rakyat pedesaan di banyak daerah di Indonesia. Perkembangan usaha pekarangan banyak ditemukan di daerah-daerah di pulau Jawa, Bali, dan daerah Minang, yang disebabkan karena keadaan sosialnya yang menganut sistem matriachat.

Fungsi pekarangan secara terperinci dapat diuraikan sebagai berikut :

• Penghasil makanan tambahan berupa sayuran dan buahan terhadap makanan pokok padi dan jagung.
• Merupakan sumber penghasilan atau uang yang dikarenakan produksi pekarangan yang beraneka, menjamin kontinyutas hasil yang sewaktu-waktu dapat dipasarkan.
• Penghasil rempah, bumbu masak, obat-obatan, dan ramuan rumah serta tanaman hias.
• Penghasil bahan bangunan, terutamam bambu dan sengon
• Sebagai sumber kayu bakar yang mensuplai energi bagi petani pengusaha pekarangan.
• Menghasilkan bahan baku kerajinan rumah (home industri), sehingga merupakan tambahan pendapatan petani.

Oleh karena adanya sistem pertanaman yang beraneka memungkinkan sistem pekarangan merupakan suatu sistem yang dapat mencegah erosi dan meningkatkan kesuburan tanah. Dari uraian di atas dapat dikatakan bahwa pekarangan merupakan : (a) warung hidup, (b) apoik hidup, dan (c) bank hidup.

KEBUN PEMBIBITAN

Bentuk kebun pembibitan banyak berkembang di daerah-daerah sekitar kota-kota besar. Hal ini dimungkinkan oleh kebutuhan masyarakat kota akan tanaman hias yang diperuntukan bagi taman-taman rumah, kantor, ibadah, rumah sakit, atau sebagai taman pot dalam rumah (indoor plants). Kebutuhan ini didorong oleh keinginan masyarkat akan suatu kondisi tenang, damai, menyegarkan, dan menyenangkan setelah berkecimpung dalam tugas-tugas rutin yang beraneka variasi di dalam kehidupan sehari-harinya.

Di luar negeri, terutama untuk usaha jenis tanaman sayuran, terdapat beberapa bentuk hortikultura, yaitu :

1. Market produktion. Suatu bentuk usaha hortikultura di sekitar areal perumahan secara kecil-kecilan sampai sedang untuk mensuplai sayuran di pasaran, terkadang diusahakan secara selektif disesuaikan dengan permintaan pasar terdekat dan keadaan lingkungan.
2. Truck farming. Banyak pengusaha pertanian yang bergerak di bidang hortikultura yang mengkhususkan diri untuk menyatukan penanaman jenis sayuran atau buahan dalam bentuk areal kebun yang luas. Produksi tanaman ini kemudian dipasarkan di daerah-daerah yang jauh, malah bermil-mil dari tempat pengusahaannya. Untuk itu produksi diangkut dengan truk ataupun dengan kereta api khusus. Dengan demikian di dalam usaha ini diperlukan cara pengolahan hasil yang baik, cara-cara pengepakan yang teratur serta membutuhkan sarana pengangkutan yang memadai.
3. Vegetable for processing. Terdapat bentuk pengusahaan sayuran yang khusus ditujukan untuk menjaga kontinyutas suplai di pasaran. Bentuk ini mengusahakan jenis sayuran yang kemudian diawetkan dengan menggunakan cara-cara : pengalengan (Canning), pengasinan (Pickling), pengeringan (Drying), dan pendinginan (Freezing).
4. Vegetable forcing. Di Amerika sebagaimana diketahui memiliki variasi musim, dimana pada musim dingin, pengusahaan di kebun adalah tidak mungkin. Untuk menjaga kelangsungan produksi, maka banyak pengusaha membangun green house untuk maksud tersebut. Di dalam green house ini, kemudian diadakan usaha-usaha untuk mengatur kondisi lingkungan yang sesuai untuk berbagai jenis sayuran yang diusahakan
5. Seed production. Pengusahaan jenis sayuran yang dikhususkan untuk mensuplai benih. Dengan demikian diperlukan banyak pertimbangan secara teknis di dalam usaha ini. Pertimbangan dan perhitungan yang tepat mengenai : (a) kondisi lingkungan lokasi, (b) keadaan sosial ekonomi, (c) teknik penanaman, (d) pengolahan hasil, (e) penenganan dan prosesing hasil, serta (f) pemasaran.

MK HORTIKULTURA 1

Mata Kuliah : Hortikultura 1


SKS : 2 SKS


Prg. Studi : Agroteknologi


Semester : 5 (lima)


Pertemuan : I (15 September 2008)


Hari/jam : Senin, 10.00 - 11.40 WIB

I. PENDAHULUAN


“General Health and Happiness of the Family are Major Objectives and Results of a good Horticultural Program for the Home.”


A. Batasan dan Ruang Lingkup

Hortikultura merupakan suatu perkataan didalam bahasa Indonesia yang sama artinya dengan Horticulture ( Inggris ) atau Gartenbau ( Jerman ). Perkataan ini pada dasarnya merupakan penggabungan dua buah kata dalam bahasa Latin, Hortus dan Colore. Hortus mengartikan kata kebun ( Garden ), dan Colore mengartikan kata pengusahaaan ( to cultivate ). Dengan demikian perkataan Holtikultura dapat diartikan dengan : Pengusahaan Tanaman Kebun atau “ Culture of Garden Crops and Plants “.
Di abad pertengahan, hortikultura atau pengusahaan tanaman kebun, dibedakan dengan agrikultura atau pengusahaan di ladang. Namun pada waktu sekarang agrikultura atau pertanian telah berkembang dan meliputi secara luas teknologi pengusahaan tumbuhan dan hewan.
Pengusahaan tanaman-tanaman hortikultura dibanyak tempat telah berkembang dan tetap dikembangkan sebagai cabang usaha komersial, baik secara pribadi, perusahaan swasta ataupun perusahaan-perusahaan Negara .
Bidang ilmu hortikultura mempunyai hubungan secara langsung dengan banyak ilmu-ilmu pertanian lainnya, termasuk ilmu-ilmu dasar, ilmu-ilmu terapan sampai kepada teknologi yang menyangkut pengolahan dan prosesing hasil ( Annex 1 ).
Di dalam kehidupan sehari-hari secara sadar maupun tidak, manusia terlibat dengan bidang hortikultura. Hal ini disebabkan ruang lingkupnya yang meliputi pengusahaan jenis-jenis tanaman sayuran, buahan, dan berbagai tanaman hias sampai kepada elemen-elemen lain yang bukan tergolong organisme hidup.
Sebagai suatu bidang ilmu, hortikultura di Indonesia digolongkan kedalam bidang agronomi. Sedangkan di negara-negara yang telah berkembang seperti di Amerika Serikat dan Eropa, hortikultura berdiri sendiri sebagai suatu cabang ilmu terlepas dari agronomi, walaupun disatu pihak keduanya membicarakan tentang pengelolaan tanaman-tanaman pertanain ( Annex 2 ).
Hortikultura merupakan suatu applied-science, sama halnya dengan agronomi ataupun kehutanan. Beberapa pokok pikiran yang dapat digunakan untuk menjelaskan perbedaan antara pengusahaan holtikutura dengan agronomi dan kehutanan, antara lain :
1. Intensitas produksi ( Intensiveness of production )
2. Tujuan Penanaman ( Purpose for which a crop is grown )
3. Adat/Kebiasaan ( Custom )
4. Sifat hasil ( Shelf-life )


INTENSITAS PRODUKSI. Didalam mengusahakan jenis-jenis tanaman hortikultura, investasi modal dan tenaga kerja serta jumlah jam kerja persatuan luas tertentu, biasanya lebih besar dibandingkan dengan pengusahaan jenis-jenis tanaman agronomi atau kehutanan. Sebagai contoh : Untuk mengusahakan tanaman Tomat dan Kubis, investasi modal, penggunaan tenaga kerja serta jam kerja yang dibutuhkan sejak pembukaan tanah/persiapan lahan, pembibitan, dan penanaman, pemeliharaan sampai kepada panen dan prosesing hasil secara keseluruhan jauh lebih intensif jika dibandingkan dengan apa yang diberikan dalam mengusahakan jenis-jenis tanaman agronomi ( Padi, Jagung, Cengkih, Kelapa, dan sebagainya ). Contoh ini tentunya dimaksudkan kepada suatu luas areal yang sama. (bandingkan Tomat/Kubis/Petsai/Apel/ Jeruk, dengan Padi, Kelapa, Jagung, Coklat, Pala, dan Cengkih per satuan luas yang sama ).

TUJUAN PENANAMAN. Berdasarkan maksud, tujuan, dan manfaat yang diberikan, beberapa jenis tanaman agronomi ini ataupun kehutanan dapat digolongkan kedalam pengusahaan tanaman hortikultura. Beberapa contoh untuk menggambarkan hal ini, antara lain: (a) Pengusahaan tanaman pinus yang ditujukan untuk pulpnya/industri kertas atau korek api, digolongkan kedalam usaha kehutanan. Apabila penanaman pohon-pohon pinus tersebut ditujukan untuk pengisian ruang disekitar gedung sekolah, gereja, mesjid, rumah ataupun jalan-jalan raya, maka hal ini digolongkan didalam hortikultura. (b) Penanaman jenis-jenis rumput tertentu yang ditujukan untuk makanan ternak, digolongkan kedalam usaha agronomi. Apabila jenis-jenis rumput yang sama diusahakan/ditanam sebagai halaman rumput disekitar gedung gereja, mesjid, rumah, sekolah, ataupun tempat-tempat rekreasi, maka hal ini digolongkan kedalam hortikultura. (c) Beberapa jenis tanaman lainnya seperti Cengkeh, Kelapa Hibrida , Damar, Akasia, Pinang, dan sebagainya, apabila bertujuan untuk menghias ruang disamping bangunan ataupun sebagai jalur hijau dan mengandung manfaat menambah keindahan ( Aesthetic ), kesemuanya ini digolongkan kedalam bidang Hortikultura ( baca ruang lingkup hortikultura ).

ADAT/KEBIASAAN. Pandangan terhadap beberapa jenis tanaman tertentu ( Nenas, Kopi, Jagung, dan Jagung manis ) terkadang agak simpang siur, apakah tergolong jenis-jenis tanaman hortikultura atau agronomi. Hal ini berlaku untuk beberapa Negara Eropa, Amerika, dan Indonesia sendiri. Namun demikia sebagai patokan dapat digunakan criteria bagaimana tingkat intensitas produksi jenis-jenis tanaman tersebut diusahakan. Sebagai missal : di Indonesia pengussahaan kopi digolongkan kedalam bidang agronomi, sedangkan di Hawaii dikarenakan pengusahaannya yang dilakukan secara intensif, tanaman kopi dan pengusahaannya digolongkan kedalam hortikultura. Demikia halnya dengan Nenas, di Hawaii sebagai tanaman hortikultura, sedangkan untuk Indonesia dibanyak tempat diusahakan secara sambilan di sisi pertanian palawija di daerah perladangan. Suatu contoh lain yaitu pengusahaan Jagung, baik di Negara-negara Eropa/Amerika/Indonesia dan ditempat-tempat lainnya, digolonh[gkan kedalam usaha agronomi, sedangkan Jagun manis yang pengusahaannya dilakukan secara intensif di kebun-kebun sekitar rumah ataupun di daerah-daerah yang luas, digolongkan kedlam hortikultura.

SIFAT HASIL. Produksi tanaman-tanaman hortikultura pada umumnya dikonsumsi dalam keadaan segar, bersifat mudah busuk serta memakan tempat. Hal ini menyebabkan produksi hortikultura tidak bias dijadikan barang pasaran timbunan, seperti halnya Padi, Kelapa , Coklat, dan Cengkih. Karena sifatnya yang mudah busuk, produksi hortikultura didalam prosesing dan pemasarannya menghendaki investasi modal yang cukup besar. Hal ini juga merupakan suatu pokok pikiran yang dapat menggambarkan perbedaan bidang hortikultura dengan agronomi. Oleh karena sifat aslinya mudah busuk, maka agar produk hortikultura dapat secara kontinyu beredar di pasaran, tentunya diperlukan teknologi yang dapat menjamin awetnya produk. Beberapa cara pengawetan yang telah dikembangkan untuk maksud tersebut, antara lain: (1) Penyimpanan/storing, (2) Pengalengan/canning, (3) Pengasinan/pickling, (4) Pengeringan/drying, (5) Pendinginan segera/quick freezing ( dibahas pada bab IV ).
Dari apa yang telah dikemukakan, jelas bahwa HORTIKULTURA merupakan pengusahaan tanaman kebun yang dilakukan secara intensif dengan produksi yang dikonsumsi dalam keadaan segar serta tidak merupakan barang pasaran timbunan karena sifat aslinya yang mudah busuk, disamping produksinya yang memak tempat.
Di Indonesia beberapa tanaman kebun yang diusahakan disamping rumah atau PEKARANGAN memiliki fungsi unik sbagai bahan rempah dan obat-obatan atau bahan baku untuk industri farmasi. ( lihat hal . . – bentuk pekarangan ).
Dari keseluruhan uraian diatas ini, lebih terperinci HORTIKULTURA dapatlah didenifisikan sebagai : Suatu cabang Agrikultura/ Pertanian yang diusahakan secara intensif dan yang digunakan manusia, segera untuk dimakan atau sebagai obat-obatan (bahan baku) industri farmasi maupun untuk memenuhi kebutuhan rohaniah dalam bentuk rasa keindahan (ESTETIKA = AESTHETIC ). Untuk itu perlu diperjelas batas dari bidang usaha dari hortikultura atau RUANG LINGKUP HORTIKULTURA (Devisions of Horticulture ). Pengusahaan jenis tanaman hortikultura mencangkup banyak tanaman yang pada prinsipnya digolongkan menjadi 3 (tiga) bagian (Devisions) yaitu :
1. Pengusahaan Tanaman Sayuran (VEGETABLES)
2. Pengusahaan Tanaman Buahan (FRUITS), dan
3. Pengusahaan Tanaman Hias dan Arsitektura Pertanaman
(ORNAMENTAL HORTICULTURE & LANDSCHAPE ARCHITECTURE)

PENGUSAHAAN TANAMAN SAYURAN. Cabang ilmu yang secara khusus mendalami maslah sayuran dikenal dengan sebutan OLERICULTURE, sehingga orang yang mengkhususkan diri dan berkecimpung kemudian menjadi ahli bidang ini, disebut OLERICULTURIST.
Pada umunya yang dimaksudkan dengan “sayur”, yaitu bagian hasil yang bisa dimakan dari tanaman kebun yang herbaseus/Herbaceous Garden Plants. Sebagai contoh: Jenis-jenis cerelia tidak bisa dikatakan sayuran, walaupun jenis-jenis tersebut herbaseus, tetapi tidak merupakan produksi kebun (bandingkan “Garden Plants atau Crops” dengan “ Field Crops “ ).
Produksi beberapa jenis tanaman kebun, juga menghasilkan kesimpangsiuran/ kekacauan didalam pengelompokan tanaman sayuran atau buahan. Beberapa diantaranya adalah : Papaya (Carica papaya), Tomat (Lycopersicum esculentum), Nangka (Arthocarpus integra, dan lain-lain sebagainya. Hal ini adalah lumrah, karena produksi “papaya” dalam bentuk bunga/daun/buah muda, digunakan sebagai sayuran. Dilain pihak buah papaya masak, dikonsumsi sebagai buahan. Buah “Nangka” yang muda, digunakan/dijual/dimakan sebagai sayuran, dilain pihak produksi buah Tomat dari beberapa varietas tertentu biasanya juga dikonsumsikan sebagai buah meja atau “Deserts”, selain sebagai sayuran (Annex 3).
Kelompok tanaman sayuran terdiri dari berbagai type dan jenis. Untuk mengadakn pengelompokan yang lebih terperinci atas group-group, dapat digunakan beberapa criteria, antara lain : Berdasarkan Umur (a), Berdasarkan Bagian Tanaman yang Dikonsumsikan (b), Berdasarkan Daerah Penanaman (c), dan Berdasarkan Toleransi Terhadap Lama Penyinaran (d).


UMUR. Berdasarkan umur atau panjangnya siklus hidup (the length of life cycle), tanaman sayuran data dikelompokkan lagi menjadi : (1) Tanaman Sayuran Semusim (annual crops : tomat, kubis,terong,dan cabe), (2) Tanaman Sayuran dua Musim (biennial crops), dan (3) Perenial crops atau menahun.

BAGIAN TANAMAN. Berdasarkan bagian tanaman yang dikonsumsikan, tanaman sayuran dibagi antara lain: (1) Root Crops (wortel, lobak), (2) Bulb Crops (bawang), (3) Tuber Clops (kentang), (4) Stems (Asparagus), (5) Flower (Kubis kembang = Cauliflower), (6) Leaves (sawi, petsai, terong, selada), (7) Grains (kacang-kacangan), (8) Fruits (Eggplants = terong, tomat dan cabe).

DAERAH PENANAMAN. Berdasarkan daerah penanaman tanaman sayuran dapat dikelompokkan atas: (1) Tanaman dataran rendah(Bayam, Kangkung, Cabe Besar, dan Terong), dan (2) Tanaman dataran tinggi (Salada, Kubis, Wortel, Bawang daun, dan Bawang putih). Namun ada beberapa jenis sayuran yang dapat/mampu diusahakan pada kedua daerah ini antara lain : Tomat, Terong, Cabe rawit, Bayam, dan Kubis jenis hibrida.

TOLERANSI TERHADAP PENYINARAN. Berdasarkan toleransi dan kecocokan terhadap lamanya waktu penyinaran ata photoperiodism, tanaman sayuran dapat dibagi atas : (1) tanaman hari – pendek (short day plants ), (2) tanaman hari-panjang (long day plants), (3) tanaman yang netral (neutral day plants) (dijelaskan pada bab III). (Annex 4-5).

PENGUSAHAAN TANAMAN BUAHAN. Cabang Ilmu yang mempelajari dan mendalami secara khusus tentang tanaman buahan dikenal dengan sebutan POMOLOGY, dan orang yang berkecimpung dan mengkhususkan diri dalm bidang ini, disebut POMOLOGIST.
Pada dasarnya yang dimaksud dengan buah, yaitu hasil dari tanaman yang berupa daging dan bisa dimakan, dan yang dihasilkan oleh tanaman berkayu atau Woody plant serta yang berasal dari bunga.
Pertanaman buah-buahan dapat dikelompokkan lagi berdasarkan besar kecilnya buah (a), berkayu atau berbatang lunak (b), ataupun berdasarkan daerah penanamannya (c), maupun kesesuain terhadap iklim.
Mengenai secara besar-kecilnya buah yang dihasilkan oleh pohon buahan secara mudah dapat dimengerti. Pohon buahan yang menghasilkan buah dengan ukuran kecil antara lain : Anggur, jenis-jenis Berry, Klengkeng, Langsat, Duku, Rambutan. Yang menghasilkan ukuran buah sedang sampai besar, antara lain: Jeruk, Apel, Pear, Advokad, Lemon, Manggis, Papaya, Duren.
Berdasarkan sifat berkayu atau lunaknya batang, pohon buahan dapat diklasifikasikan sebagai berikut :
I. Fruits borne on woody plants
(Tanaman /pohon buahan berkayu)
A. Tree fruits
1. Decidious : Apel, Pear, Kedondong (gugur daun)
2. Evergreen : Jeruk, Lemon, Advokad, Manggis
(tidak gugur daun).
B. Small fruits.

II. Fruits borne on herbaceous parennial
A. Prostrate growth (merayap) : Strawberry dan Anggur.
B. Upright growth (bertumbuh tegak) : Pisang dan Nenas.

Beberapa pohon buahan menghendaki daerah dataran tinggi sebagai tempat pengusahaannya untuk dapat memproduksikan kwalitas dan kwantitas buah yang baik. Demikian pula terdapat pohon buahan yang menghendaki penanamannya di daerah dataran rendah. Dataran tinggi : Apel, Klengkeng, dan jeruk manis . Sedangkan untuk Dataran rendah : sesuai untuk banyak jenis pohon buahan.
Terdapat pohon buahan yang menghendaki iklim basah dengan muka air tanah yang tinggi, antara lain : Buah nona, sukun, Duren, Jambu air, Duku, dan Pisang ambon. Sebaliknya yang menghendaki ilim kering antara lain: Srikaya, Jambu mete, Jeruk siam, dan Mangga.
Perlu diketahui bahwa tentunya di antara percontohan jenis-jenis pohon buahan diatas, terdapat jenis-jenis pohon buahan yang bisa saja cocok untuk dataran tinggi maupun dataran rendah, demikian pula ada yang cocok untuk iklim basah maupun daerah iklim kering. Sebagai contoh : Jeruk siam (Citrus sinensis), Kecapi (Sondarikum Kocape), Manggis (Garcinia manggostana), Pisang (Musa Paradisiaca), Advokad (Percea Americana), Nenas (Ananas commosus), dan Anggur (Vitis vinivera).


PENGUSAHAAN TANAMAN HIAS DAN ARSITEKTURA PERTAMANAn
“ Habits an Custom differ, but all people have
the love of flower in common”

Tanaman hias atau “Ornamental-Crops” meliputi banyak jenis tanaman yang pada dasarnya diusahakan untuk dapat dinikmati keindahannya serta unutk memenuhi salah satu kebutuhan rohaniah. Dengan demikian yang dapat digolongkan tanaman hias, mulai dri tanaman berbunga, rumput, semak, sampai kepada jenis pohon.
Bidan ilmu yang mempelajari tentang tanaman hias disebut “FLORICULTURE”
, sehingga seseorang yang berkecimpung dan mengkhususkan dirinya dibidang ini biasanya dikenal dengan FLORICULTURIST.
Dibidang “floriculture” ini kemudian dapat dibagi lagi secara lebih khusus menjadi:
1. Pembibitan (Nursery) : Khusus mempelajari tentang cara-cara dan pembibitan dari jenis tanaman hias.
2. Arboriculture : Merupakan bidang yang mempelajari tentang hal-hal yang menyakut pemeliharaan, penanaman, dan perencanaan di dalam pengusahaan tanaman hias.
3. Landschape Architecture : Meliputi perencanaan, penanaman, pengaturan dan pemeliharaan tanaman-tanaman taman pada gedung-gedung, jalan raya, gereja mesjid, dan berbagai tempat rekreasi.
4. Cut Flower (Bunga Potong) : merupakan bidang yang mengkhususkan diri di dalam pengusahaan bunga potong seperti : Tulip, Amarilis, gladiol, Aster, Mawar, Anggrek, dan krisant
5. Bonzai : Situ bidang yang mengkhususkan pengusahaan tanaman-tanaman hias yang dikerdilkan dan ditanam di dalam pot-pot khusus.

Untuk memberikan gambaran lebih lebih luas mengenai “Cut Flower” dan “Bonsái”, dapat dikemukakan beberapa hal seperti yang dituangkan di bawah ini :
CUT FLOWER. Cut Flower atau bunga potongan merupakan statu usaha yang sudah lazim dikenal . diberbagai kota besar di Indonesia dan di banyak tempat di luar negeri, bunga potongan ini menempati fungís khusus dalam kehidupan manusia.
“Say it with flower”, demikian salah satu slogan di Amerika di mana hal inipun berlaku umum di berbagai tempat. Pada saat ulang tahun, pesta pernikahan ataupun banyak desempatan lanilla dengan perantaraan diriman bunga-bunga potongan dalam bentuk keranjang, banyak orang telah menyampaikan ucapan selamat yang satu lepada lainnya.
Perkembangan pengusahaan bunga potong pada saat Semarang ini, telah maju dengan pesatnya. Secara nyata beberapa faktor atau keadaan yang mendorong dan menunjang berkembangnya pengusahaan bunga potong ini antara lain :
Adanya perkumpulan-perkumpulan tertentu yang bergerak di bidang ini, di Indonesia FAPI (Federasi Anggrek Potong Indonesia) di Amerika dengan nama Society of American Florist, PAI (Perhimpunan Anggrek Indonesia)
Adanya badan-badan tertentu yang memberikan ”JASA” di bidang ini. Di Indonesia terdapat pengusaha-pengusaha yang mengkhususkan diri untuk menyediakan atau mengantarkan keranjang hias (ulang tahun, pernikahan, orang yang meninggal dunia, dan sebagainya). Di Amerika terdapat Floris Telegraph Delivery Association (FTDA) yang dapat menyampaikan pesan keranjang hias dari seseorang kepada kerabat atau kenalannya melalui telephon. Kegiatan ini bukan saja dilakukan di dalam suatu kota, tetapi antar kota maupun antar pulau.
Perkembangan teknologi sehingga dapat memperpanjang atau menunda saat kelayuan dari bunga-bunga potong (Plant food, Growth-Regulator, Fertilizer, dan lain-lain).
Perkembangan atau pertambahan jumlah penduduk.
Perkembangan dan penyebaran kota (adanya pembentukan kota-kota satelit atau real estate).
Pembentukan staff tata-kota (di Bogor : City Beautification Commitee, di Jakarta dan Ambon Dinas Tatta Kota), dan lain-lain.

BONZAI. Bonzai merupakan suatu perkataan dalam bahasa Jepang, yang kurang lebih berarti seni mengusahakan tanaman mini dengan jalan pengkerdilan secara ekstrim (Bonzai = Japanese art of growing miniature trees and schrubs by extreme dwrafing).
Biasanya dalam pengusahaan Bonzai ini, dipergunakan cara-cara, antara lain : (a) penggunaan zat pengatur tumbuh (Growth Regulator), (b) pemangkasan akar atau daun (Prunning), dan (c) pengaturan bentuk (Trainning). Zat-zat pengatur tumbuh yang digunakan dapat bermakna sebagai zat penghambat tumbuh (Growth Retardants) atau zat tumbuh (Growth Hormones). Beberapa contoh retardants antara lain : Cycocel (CCC), Allar(B-9). Beberapa contoh hormone, antara lain : NAA, Giberallic Acid (GA), Cytokinine, Kinetine, IBA, 2-4 D, dan lain-lain . zat tumbuh dalam konsentrasi tertentu merupakan retardants, malahan dapat mematikan.

Insect - Fungal - Bacterial & Viral

Insects

It is commonly assumed that hydroponic agriculture systems are relatively free of insect pests and plant diseases because the technology is mostly enclosed. Unfortunately, this is not true. Pest populations can increase with alarming speed in greenhouses because of the lack of natural environmental checks.

The frightening ability of some insects to develop resistance to pesticides has revived worldwide interest in the concept of biological control: the deliberate introduction of natural enemies of pest insects, particularly when used in association with horticultural practices, plant genetics and other central mechanisms.

While there are many pests and diseases which attack tomatoes, below is a list of a few of the major pests associated with hydroponic tomato production and their control.

Whiteflies

There are about 1,200 different species of whiteflies. They are pests in many important agricultural and horticultural crops, both inside and outside the greenhouse environment.

Trialeurodes vaporariorum

The greenhouse whitefly (Trialeurodes vaporariorum) has been a problem for greenhouse tomatoes in the U.S. since 1870. Originally from tropical or subtropical America , probably Brazil or Mexico.

Life cycle of the greenhouse whitefly:

• Females lay eggs on the undersides of new leaves. Eggs are white at first, oval shaped, and about 0.25mm in diameter. After 1 or 2 days, the eggs turn brown to black. The larvae emerge after 7 to 10 days.
• The larvae are transparent, 0.3mm-0.7mm in size, mobile at first, but become immobile after the first few hours, at which time they begin to feed. They are oval shaped, and deposit much wax at this stage.
• At the pupa stage, the red eyes of the growing adult become visible. The pupa is dirty white, and surrounded by much wax and honeydew.
• The adult whitefly emerges from the pupa and begins to eat. Adults are 1mm long with two pairs of white wings and a light yellow body. They are generally found at the top of the plant. Females start laying eggs within 1 to 2 days, and may lay up to 500 eggs in a lifetime.

Length of the life cycle depends on temperature, ranging from 4 weeks at 27 ° C to over 8 weeks at 14º C degrees. Damage is caused by flies and larvae sucking the leaf sap, which can cause stunting, leaf drop, and reduced yield. Honeydew deposits on fruit are sticky and can mold, making the fruit unmarketable. Greenhouse whitefly can transmit viruses. And although whiteflies cannot hibernate, the eggs of the greenhouse whitefly can survive for about 5 days at temperatures of -6° C.

Bemisia tabaci

Tobacco whitefly, Bemisia tabaci, also known as the sweetpotato, silverleaf, or cotton whitefly, first occurred in Greece in 1889 on tobacco. It was discovered in Florida in 1900. It is the predominant pest on cotton in the United States due to the insects' increased resistance to insecticides. It resembles the greenhouse whitefly except it is slightly smaller and more yellowish, and holds its wings closer to its body. The lifecycles of the two species are quite similar. The eggs are easy to distinguish from each other, B.tabaci are yellowish green and do not change to brown. Longevity depends on temperature, at high temperatures the female lives 10-15 days, at lower temperatures they can live up to 2 months. Adults can live for an extensive time even without host plants in an empty greenhouse, however, they cannot survive temperatures below freezing. B.tabaci can transmit many viruses, including Tomato Yellow Leaf Curl Virus (TYLCV).

Natural enemies of whiteflies

There are several natural predators of whiteflies, however they tend to be very specific to particular species of whitefly hosts, therefore correct identification of the pest is critical. Any pesticide residues may adversely affect the predator population, so careful attention to integrated pest management practices are essential to the success of any biological control effort.

Encarsia formosa

Encarsia formosa is a tiny parasitic wasp of T.vaporariorum (greenhouse whitefly). The larvae of this wasp develop inside the whitefly larvae or pupae. The parasitized greenhouse whitefly larvae are easy to recognize because they become black after about 10 days as the young wasp develops inside. Although Encarsia prefer greenhouse whitefly, they can also parasitize B. tabaci, in which case the parasitized larvae become transparent to brown in color. Adult wasps emerge from the whitefly pupa approximately 21 days after parasitization through a neat, round hole. The female adult wasp is about 0.6mm long, with a black head and thorax and a yellow abdomen. The adult wasps feed on the honeydew and body fluids of whitefly larvae. Encarsia develop faster than whiteflies, with lifecycles ranging from 3 weeks at 27ºC to 2 months at 14ºC . The population of Encarsia is almost 98% female and mating is not necessary for reproduction. The female can lay about 300 eggs in a lifetime, most of which will be more females (this is called parthengenetic reproduction).

Eretomocerus californicus The tobacco whitefly can be parasitized by Encarsia, but they are controlled better by Eretomocerus species. The Eretomocerus is another tiny parasitic wasp about the same size as the Encarsia, but without the dark head and thorax of the Encarsia species. Abundant in the Southwest U.S., Eretomocerus is reported to be well adapted to extremes of temperature and humidity, and also more resistant to pesticides than some other whitefly parasites. Females lay about 3 to 5 eggs per day, but they can also kill whitefly nymphs by repeatedly probing with their ovipositors and feeding on the haemolymph (blood) that exudes from the wounds.

Verticillium lecanii

Verticillium lecanii is a common soil borne fungus which affects several different kinds of insects. It is widespread in temperate and tropical areas, but cannot infect birds, fish, mammals or plants. It was first observed on whitefly in 1915. It has a white to light yellow cotton-like appearance. The whitefly dies from infection before the fungus even becomes visible; the fungal spore germinates and begins to grow on the honeydew secretion on the whitefly body. It can either infect the insect or directly penetrate the insect. Since the fungus is not mobile and cannot seek its host, it is only effective in very high densities of white fly and repeated applications are necessary.

Tomato Fruit Worm

Heliothis armigera - The larva of this insect feeds on a number of plants including tomato, corn and cotton. It is sometimes called the corn earworm or the cotton bollworm. On tomato it burrows in the fruit of the tomatoes. The adult is a moth that is light yellowish in color. Control with sprays of Bacillus thurengiensis (B.t.), which is compatible with other biological control agents.

Other pests common to hydroponic tomato production are leaf miner, tomato pinworm, cabbage looper and two-spotted spider mites. Consult your local agricultural experiment station or agricultural university for identification and control. Good sanitation is important in hydroponic tomato production, so weeds and other debris should not be allowed in and around the greenhouse as they can become a harbor in which pests can hide and multiply. A clean strip around the greenhouse, free of any plants and debris, is important.

Harvest

Flavor is the ultimate test of a good quality hydroponic tomato. However, there are other factors that determine overall quality: color, texture, firmness, shelf life, and nutrient levels are all important quality indicators. The single most important factor in all these issues (especially flavor) is the genetic makeup of the plant, so careful selection of the proper cultivar for the growing conditions is absolutely necessary.

The level of maturity at the time of harvest is the another important factor affecting final fruit quality. For commercial trade, tomatoes are harvested mature but unripe, often called the "mature green" stage. U.S. standards for grades of vegetables define a mature tomato as the one in which the contents of two or more seed cavities have developed a jelly-like consistency and the seeds are well developed.

Mature fruit produce large quantities of ethylene, which will hasten ripening, increasing the carotenoids (red and yellow colors) and decreasing the chlorophyll (green color). Therefore, harvested fruit should be stored in well-ventilated areas, or in a low oxygen or high carbon dioxide atmosphere. The fruit should never be exposed to temperatures below 54° F (12.5° C) or chilling injury may result. In tomatoes, chilling injury can appear as pitting, shriveling, softening, uneven ripening, seed discoloration, or increased susceptibility to rot. Optimum ripening temperatures for tomatoes are 68-72° F (20-22° C), and an ethylene treatment of 100 ppm for 24 to 48 hours can be effective in producing evenly ripe fruit.

The major cause of postharvest losses in tomato is physical damage. To prevent puncture wounds from stems, the calyx and stem should be removed from the fruit immediately at harvest; although many growers will leave the calyx on the fruit in order for the consumer to recognize the fruit as greenhouse grown. Tomato picking crews must be well trained in placing the harvested fruit in the picking boxes. Many large greenhouse facilities have an extensive system of canals to float the fruit from the growing areas to the packing rooms, thereby minimizing physical damage to the fruit. Another cause for postharvest loss is desiccation. In tomato, about 65% of the water loss occurs through the stem scar. Optimum relative humidity levels for harvested tomato fruit is high, in the 90-95% range.

Pollination

Tomato flowers are normally wind pollinated, however there is not enough air movement in a crowded greenhouse to ensure good pollination. Therefore, growers have two options for pollinating their crop: mechanically pollinate or maintain hives of bumblebees in the greenhouse.

Mechanical pollination entails shaking or vibrating each flower cluster at least every two days when humidity and temperature conditions are best. Generally, midday and early afternoon during sunny conditions when humidity is about 70% is best. Greenhouse temperatures should be kept above 65° F (15° C) at night and below 85° F (29° C) during the day. Even if conditions are not ideal, pollination should be attempted. Although tapping or shaking the entire vine will move some pollen, the best approach is to use an electric vibrator on each truss. Commercially available pollinators have a very forceful action, battery operated toothbrushes also work well.

The more efficient method of pollinating large greenhouses of tomatoes is through the use of bumblebees. However, maintaining a healthy hive requires an integrated management approach. It is imperative that there is a proper balance of tomato flowers and bees. One hive will work approximately one half acre (0.2 hectare) of tomatoes. Bumblebee hives cost several hundred dollars each, and may only last a few months. The hives are housed in cardboard boxes with a sugar water solution to supply a balanced diet for the bees. The bees pose no threat to people working in the greenhouse, but will be devastated by any insecticides used on the crop. Therefore, bumblebee pollination works well in pesticide-free greenhouses, assuring efficient, complete pollination.

A quote from the Penn State University program perspectives sums up the use of bumblebees well: "Tomato growers who eliminate pesticides in the greenhouse can use bumblebee hives to pollinate their crops, saving 15 hours of labor per acre [per day] required for manual pollination. Research indicated that bumblebees pollinate more efficiently, leading to yield increases of as much as 25 percent."

Plant Nutrition

Water Quality

Good, consistent water quality is essential for hydroponics. Fresh water free from pesticide runoff, microbial contamination, algae, or high levels of salts must be available throughout the year. The levels of pH and alkalinity (measured as carbonates and bicarbonates) of the raw water affects the absorption of certain nutrients by the roots. Water pH levels above the desirable range (5.0 to 7.0) may hinder absorption of some plant nutrients; pH levels below this range permit excessive absorption of some nutrients, which may lead to toxic levels of those elements.

In arid areas, or areas near salt water, the concentration of sodium chloride (NaCl) may be too high for optimal plant growth (greater than 50 parts per million or 1.5 mmol/liter). The hardness of the incoming water will also have an effect on the nutrient solution. Hardness is a measure of the concentrations of calcium and magnesium carbonates, which are often quite high in areas of limestone rock. The naturally occurring concentrations of these minerals in hard water must be taken into consideration when calculating the amount of nutrient salts to add to the nutrient solution, and may interfere with the availability of other essential nutrients, such as iron. Similarly, concentrations of other essential elements may be found in very high levels in poor quality water. For example, water may carry high levels of iron, selenium, boron, or sulfur; and municipal water may have undesirably high levels of chlorine.

The electrical conductivity of good quality raw water should be below 0.5 mS/cm or mmhos/cm. It is advisable to invest in a complete analysis of the water quality, including all major and minor elements, microbial contamination and pesticide residues before any further work is done.

For more information on desirable ranges for specific elements in irrigation water, see Jensen and Malter, 1995, referenced in the Links and References section of this website.

Nutrient Solution Recipes

There are sixteen elements which are generally considered to be essential for good plant growth. The macro elements are those required in "high" concentrations: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Sulfur (S), and Magnesium (Mg). Carbon must be supplied to the plant as carbon dioxide gas (CO₂). In a small operation or one with large amounts of fresh air movement, additional CO₂ may not be required. Larger operations, or ones with high density plantings will need a CO₂ generator (See CO₂ enrichment, detailed below). Hydrogen is available in sufficient quantities from the atmosphere and oxygen is supplied from well-aerated nutrient solutions. Nitrogen, phosphorus, potassium, calcium, sulfur and magnesium must all be supplied by the nutrient solution.

The micro elements are also essential for growth, but required in smaller concentrations. There is still some disagreement, but generally the micro elements are thought to be: Iron (Fe), Chlorine (Cl), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), and Molybdenum (Mo). Certain plant species may need others for good growth: Silica (Si), Aluminum (Al), Cobalt (Co), Vanadium (V), and Selenium (Se).

Small greenhouse operations often buy ready-made nutrient formulations, only water need be added to prepare the nutrient solution. Larger facilities prepare their own solutions. The commonly used salts and the required amounts to make 1000 liters of 1 ppm solution are given in Table 1. Multiplying the value for a salt by the number of ppm desired in the formula will yield the number of grams to be used per 1000 liters.

Table 1. Fertilizer salts (adapted from Jensen and Malter, 1995)

Fertilizer Salts	element supplied	grams of fertilizer needed per 1000 liters of water to provide 1 mg/l (ppm) of the nutrient specified
Boric Acid [H3BO3]	B	5.64
Calcium nitrate [Ca(NO3)2·4H2O] (15.5-0-0)	N	6.45
	Ca	4.70
Cupric chloride [CuCl2·2H2O]	Cu	2.68
Copper sulfate [Cu(SO4)·5H2O]	Cu	3.91
Chelated iron (9%)	Fe	11.10
Ferrous sulfate [FeSO4]	Fe	5.54
Magnesium sulfate [MgSO4·7H2O] (Epsom salts)	Mg	10.75
Manganese chloride [MnCl2·4H2O]	Mn	3.60
Manganese sulfate [MnSO4·4H2O]	Mn	4.05
Molybdenum trioxide [MoO3]	Mo	1.50
Monopotassium phosphate [KH2PO4] (0-22.5-28)	K	3.53
	P	4.45
Potassium chloride [KCl] (0-0-49.8)	K	2.05
Potassium nitrate [KNO3] (13.75-0-36.9)	N	7.30
	K	2.70
Potassium sulfate [K2SO4] (0-0-43.3)	K	2.50
Zinc sulfate [ZnSO4·7H2O]	Zn	4.42

Nutrient solutions need to be adjusted during the growing cycle of the crop and are different for each crop grown. Leaf crops generally need higher N, root crops need higher K, and fruit crops such as tomatoes or cucumbers should maintain relatively low N levels.

The nutrient solution for tomatoes is generally made in two or three levels for the various stages of growth (see Table 2, below). Only the macro nutrients change, becoming progressively more concentrated as the crop matures. The micronutrients remain the same throughout the growth cycle. The first stage of growth (Level A formula) is for seedlings from the first true leaf until the plants are 24 inches (62 cm) tall, when initial fruit is 1/4 - 1/2 inches (1 to 1.5 cm) in diameter. After that, Level B formula is used. While the formula in Table 2 has been standard for many years, some new tomato varieties may require much higher nitrogen and potassium. It is advisable for commercial growers to consult their seed company for the recommended nutrient formulas for the tomato variety grown. Optimizing the N:K ratio is important as the crop matures and as the available light and day length changes. Under high light conditions, plants use more N. High K during the fall and early winter months improves fruit quality. It is common practice to double the ratio of K:N during winter months when plants receive less light. The optimum pH of the nutrient solution should be 5.5-6.0. The pH of the nutrient solution can be lowered with phosphoric acid.

Table 2. Preparation of macronutrient and iron solutions for tomato (adapted from Jensen and Malter, 1995)

	Chemical compound (fertilizer grade)	Level A seedlings to first fruit set (g/1000 liters)	Level B Fruit set to harvest (g/1000 liters)		Nutrient	Level A (ppm or mg/L)	Level B (ppm or mg/L)
	Magnesium sulfate (Epsom salts)	500	500		Mg	50	50
	Monopotassium phosphate (0-22.5-28)	270	270		K	199	199
	Potassium nitrate (13.75-0-36.9)	200	200		P	62	62
	Potassium sulfate (0-0-43.3)	100	100		N	113	144
	Calcium nitrate (15.5-0-0)	500	680		Ca	122	165
	Chelated iron	25	25		Fe	2.5	2.5

The micronutrients should remain at the same concentration throughout the life of the crop. Optium concentrations for tomatoes are: Boron 0.44, Copper 0.05, Chlorine 0.85, Manganese 0.62, Molybdenum 0.06, Zinc 0.09, Iron 2.5 ppm (mg/L).

Table 3. Preparation of micronutrient stock solution for tomatoes. Use 250 mL of this micronutrient stock in each 1000 liters of nutrient solution from Table 2, above. (adapted from Jensen and Malter, 1995)

Fertilizer Salt	grams of chemical in 450 mL stock solution
Boric acid	7.50
Manganous chloride	6.75
Cupric chloride	0.37
Molybdenum trioxide	0.15
Zinc sulfate	1.18

If a concentrated stock solution is used for the macronutrients, then the calcium salts should be kept apart from the other salts in a separate solution. Nitric or phosphoric acid can be used to lower the pH if necessary; concentrated acid should always be carefully diluted before it is added to the stock solutions.

Symptoms of Nutrient Deficiencies and Toxicities

Nutritional disorders can be very complex, involving temperature, humidity, day length and disease as well as nutrient levels. Multiple disorders can produce a syndrome which does not resemble any single disorder. Some growers feel that relying on plant disorder symptoms is a reactive, not a pro-active approach, since by the time symptoms appear, the yields will already have been adversely affected. Symptoms of nutritional disorders should never be ignored, however, and excellent sources of information are available to key out specific problems (see section on Links and References in this website). Professional growers should keep such sources and horticultural experts near at hand, and have their nutrient solutions analyzed routinely. Table 4 outlines some common nutrient disorder symptoms in tomatoes.

Table 4. Common Nutrient Disorders in Tomatoes (adapted from Resh, 1995)

Element	Deficiency	Toxicity
Nitrogen	older leaves are chlorotic (yellow), spindly plants, small fruit remedy: use foliar spray of 0.25% to 0.5% solution of urea	plants dark green with abundant foliage but little root growth or fruit production, flower drop
Phosphorus	plants stunted, maturity delayed, purplish color under younger leaves	no recognizable symptoms, however Cu and Zn deficiencies may occur in presence of excess P
Potassium	older leaves chlorotic, with scattered dead spots. uneven ripening in fruit (blotchy) remedy: use foliar spray of 2% potassium sulfate	not usually absorbed by plants in excessive amounts, but high levels may lead to deficiencies in Mg, Mn, Zn, or Fe
Sulfur	S deficiency is very rare, some yellowing in young leaves, upper leaves become stiff and curl downward. stems, veins, and petioles turn purple	stunted growth, may see interveinal yellowing or leaf burning
Magnesium	interveinal chlorosis on older leaves remedy: use foliar spray with 10% magnesium sulfate	no visual symptoms
Calcium	Blossom end rot on fruit, yellowing on margins of young leaves, undersides turning purple, curling of leaves. growing tip and root tip death, thick woody stems. can be caused by boron deficiency remedy: foliar spray of 0.75 to 1.0% calcium nitrate solution or 0.4% calcium chloride	no visual symptoms
Iron	pronounced interveinal chlorosis on young leaves, starting at margins and spreading through entire leaf. stunted growth and aborted flowers. High pH can lead to iron deficiency, low pH can lead to preferential uptake of aluminum, restricting iron absorption remedy: foliar spray with 0.2 to 0.5% iron chelate every 3 to 4 days	not usually a problem
Chlorine	very rarely a problem, but manifests as wilted leaves, chlorotic with a bronze color. stunted root growth	burning of leaf tips, bronzing or yellowing, leaf drop and stunted growth
Manganese	interveinal chlorosis on older leaves, light green leaves with dead patches ringed in yellow, few flowers or fruit remedy: foliar spray using 1% solution of manganese sulfate	chlorosis, stunted growth
Boron	growing points wither and die, interveinal chlorosis of upper leaves, brittle leaves. boron deficiency can lead to calcium deficiency remedy: use a foliar spray of 0.1 to 0.25% borax	yellowing of leaf tip, leading to browning
Zinc	reduction of internode length, puckered margins on leaves, brown spots on petioles, small leaves, sometimes long and narrow remedy: foliar spray with 0.1 to 0.5% solution of zinc sulfate	commonly accompanied by Fe chlorosis
Copper	young leaves dark green and misshapen, curling into a tube, petioles bent downward, few or no flowers remedy: use foliar spray with 0.1 to 0.2% solution of copper sulfate to which 0.5% hydrated lime has been added.	reduced growth, symptoms of Fe chlorosis
Molybdenum	interveinal chlorosis on older leaves, margins of leaves curl up upward remedy: foliar spray with 0.07 to 0.1% solution of ammonium or sodium molybdate	tomato leaves turn golden yellow

As soon as any deficiency is confirmed, the nutrient solution should be changed with the concentration of the deficient element increased 25 to 30%. After the deficiency is rectified, the concentration should be lowered back down to slightly higher than normal levels. Foliar sprays can be applied for a faster response, however burning of the plants may result. It is best to test a foliar spray on a few plants and wait several days to observe the effects before spraying a whole crop.

Sampling (Nutrient Solution and Plant Tissue)

Nutrient solution analysis is absolutely necessary in a closed system, where the solution is re-used, and recommended in an open system to verify concentrations of macro and microelements. Plants take up nutrients in varying amounts depending on their needs. Although monitoring pH and EC will give an indication of changes in the nutrient solution, it cannot indicate changes in preferential uptake of particular ions. In a closed system, if no analysis is possible, then the nutrient solution should be completely changed every two weeks.

Plant tissue analysis can provide other information about the growing system. That is, tissue analysis can indicate any problems the plants may be having in absorbing nutrients which are present in the solution. For example, fluctuating pH levels, high cation exchange capacity of the media, high humidity, or diseases and nematodes can prevent nutrient uptake by a plant.

On a commercial scale, nutrient solution and plant tissue analysis is absolutely required. Plant tissue analysis allows the grower to detect a problem in the uptake/assimilation of nutrients which may not be apparent in a nutrient solution analysis. Consult with the testing laboratory for information on sampling and sample prep. For more information on expected levels of individual elements in tomato tissue analysis, see Hydroponic Food Production by Howard Resh, 1995, (cited in the Links and References page of this website).

Electrical Conductivity (EC) is a convenient estimation of Total Dissolved Solutes or Total Dissolved Salts (TDS) in the solution. However, although EC is a function of the salts in the solution, it does not indicate the relative concentration of the major nutrients, or the quantitiy of trace elements (micro nutrients) present. For example, high levels of calcium can give a lower EC reading than the equivalent concentration of sodium ions. A grower would not be able to detect these changes by monitoring EC alone. Although changes in TDS and EC can indicate a change in the nutrient solution, they should not be relied on exclusively.

Carbon Dioxide Enrichment

Carbon dioxide is necessary for growth, and optimal levels for tomatoes may be 2 to 5 times the normal atmospheric levels (1000 to 1500 ppm CO₂ versus ambient levels of 350 ppm). Plants can deplete the CO₂ in a closed greenhouse in a matter of hours, significantly reducing growth rates. Growers using CO₂ enrichment have claimed to see a 20 to 30% increase in tomato yields, and accelerating flowering and fruiting by as much as 10 days.

Specially designed CO₂ generators are natural gas or propane burners hooked up to sensors. Large commercial growers often use the flue gases from a hot water boiler burning natural gas as a source of CO₂, or they will use bottled CO₂. It is important that the CO₂ be free of contaminate gases, as tomatoes are extremely sensitive to many gases, especially ethylene. Plants enjoying elevated levels of CO₂ can be expected to increase fertilizer and water requirements.

Propagation

Seeds

Several tomato varieties have been specifically developed for hydroponic production in controlled environments. All varieties have indeterminate morphology; meaning vegetative growth of the plant is continual and does not stop once flowering begins. This creates long tomato "vines" which must be trained up strings hanging from the greenhouse structures to maximize space and manage the crop. Some of the more popular varieties are Apollo, Belmondo, Caruso, Dombito, Larma, Perfecto, Trend and Trust. These are hybrid varieties, and the seed can be rather expensive. This may lead some novice growers to consider germinating seed from mature fruit, but those successive generations will not necessarily have the same characteristics of the parent plants. Some hobbyists prefer to grow successive generations from vegetative cuttings, producing genetic clones from the original plants. This is okay on a small scale, however, the high risk of perpetuating a latent disease or pest problem on a large scale outweighs the cost of new seed.

Starting Media and Nutrients

Any propagation medium must be thoroughly soaked before seeds are sown to assure uniform distribution of moisture. There are many different propagation media available.

Seeding trays can be filled with a soilless mix, such as peat and perlite. Peat pellets are also popular starters. Seedlings grown in a soilless mix may have enough nutrients available to them from the media that they would not need any additional nutrients for the first few weeks of growth, and therefore could be watered with fresh water only. However, seedlings in an inert medium, such as rockwool or oasis, will definitely require nutrient solution at all times.

Rockwool blocks are available in several sizes, and are designed so that seeds can be placed directly into seeding cubes, then, as the plants develop, the cubes can be nested inside larger blocks, for a "pot in a pot" system. This minimizes transplant shock, since the larger block consists of the same material as the germination cube. Oasis horticubes are similar to rockwool cubes in that they are inert, sterile blocks with excellent drainage. Other cubes made of urethane foam and paper fiber are also available.

Tomato seeds should be sown ¹/₄ to ³/₈ inch (0.6 to 1 cm) deep. Sprinkle a thin layer of vermiculite over the seeds or cover the germination cubes or pots with a large piece of clear plastic to conserve moisture at the surface. Avoid the use of plastic if the cubes receive direct sunlight, as the temperature may get too hot for good germination. The plastic must be removed as soon as emergence begins.

Seedling system design

Overhead watering is the most common method used for germinating seedlings. It is important for the seedlings to be in full sun and at the proper temperature as soon as germination occurs. When watering, the water must be sprinkled uniformly over all seedlings to avoid uneven growth. The plants must be checked often to assure they do not become water stressed.

Flood and drain (ebb and flow) systems can also be very effective for germinating seedlings. Nutrient solution or water floods a shallow tray containing the sown cubes or pots, providing moisture from the bottom, which will diffuse throughout the propagation block by capillary action. Once the blocks are evenly moist, the tray is drained, which allows the cubes or pots to drain and assure aeration of the roots. This process will need to be repeated often throughout the day, but may not need to be done at all during the night. The advantages of this system are even moisture, no physical beating of the leaves and tender plants, and low labor costs (especially if timers are used).

In any event, the temperature of the irrigation solution should be at least 18° C (64° F). Irrigating seedlings with colder water will result in slower growth. During winter months, especially in Northern latitudes, supplemental light may be required for strong growth of seedlings. The lights should operate 14 to 18 hours per day.

Transplanting

The three stages of early development are germination, post-emergence, and transplant. Germination should occur within one week of seeding, post-emergence is generally 5 to 12 days, and transplanting should be done between 12 and 14 days from seeding. Once true leaves appear (during post-emergence), seedlings should be transferred into larger growing blocks (pots) from the original seedling cubes, then evenly spaced to maximize light to each plant, without any crowding or shading. The transplants must be spaced so as not to touch one another, and may need to be spread several times during their growth. If crowded, the plants will become spindly. A good transplant is one that is as wide as it is tall. If plants are somewhat "leggy", with long stems, they can be transferred into the larger blocks with their stems bent 180° , so the original cube is upside-down inside the larger block, and the main stem forms a "U" shape, emerging vertically upward from the block. Tomato plants readily grow adventitious roots from the stems if given the opportunity, producing a stronger plant with more roots. Adventitious roots will grow from the bent stem inside the block.

Transplanting into the final growing media should be done before any flowering. The final growing media should be properly leached and moistened and be at the proper temperatures before plants are brought in. Plants should be irrigated with nutrient solution immediately after moving.

The spacing of tomatoes in hydroponic systems can be much denser than in soil. As little as two square feet per plant (0.2 square meters per plant) have been used with good yields and quality under high light conditions. Spacing is a function of sunlight, so in areas of lower light wider spacing should be applied.

Indeterminate tomatoes must be trained up support strings immediately after transplanting. The strings should be hung from horizontal wires, which are connected to the frame of the greenhouse. These wires will need to support hundreds of pounds of weight, as each mature plant with fruit may weigh 20 to 30 pounds (7 to 14 kilograms). Additional vertical poles can be added to help support the horizontal wires. The wires and strings should be put in place before any other paraphernalia is brought into the greenhouse, and should be at least 10 feet (3 meters) above the ground. The strings should not be re-used, however, a variety of clips are available which can be sterilized and re-used. As the plants grow, the strings are unwound from their hangers and moved along the horizontal wire, effectively "lowering" the plants without breaking them. Mature indeterminate tomato plants may be 40 feet (12 meters) in length, and can grow much more.

Double cropping

Some growers prefer to grow two crops of tomatoes in the growing media before tearing the system down, cleaning and sterilizing, and starting again. In this management system, young plants would be planted in the media between the older plants, just as the older plants are reaching their maximum economic life span. This effectively overlaps the crops, increasing total annual yield. However, the older plants must still be completely removed to prevent buildup of disease and excessive shading of the new crop, and care must be taken to work around the younger plants. In high light regions of the world, such as deserts and equitorial latitudes, the first crop is generally planted in midsummer and lasts through to the end of the year. The second crop can be planted in January and continue through the end of June. Alternatively, one long crop planted in late summer or fall can be grown until July.