APPROPRIATE TECHNOLOGY TRANSFER FOR RURAL AREAS

www.attra.ncat.org

ATTRA is the national sustainable agriculture information center operated by the National Center for AppropriateTechnology under a grant from the Rural Business-Cooperative Service, U.S. Department of Agriculture. Theseorganizations do not recommend or endorse products, companies, or individuals. ATTRA is located in theOzark Mountains at the University of Arkansas in Fayetteville (P.O. Box 3657, Fayetteville, AR 72702). ATTRAstaff members prefer to receive requests for information about sustainable agriculture via the toll-free number800-346-9140.

By Mardi Dodson,Janet Bachmann,and Paul WilliamsMarch 2002

OOOOORGRGRGRGRGANICANICANICANICANIC G G G G GREENHOUSEREENHOUSEREENHOUSEREENHOUSEREENHOUSE T T T T TOMAOMAOMAOMAOMATOTOTOTOTO

PPPPPRODUCTIONRODUCTIONRODUCTIONRODUCTIONRODUCTION

HORTICULTURE PRODUCTION GUIDE

INTRODUCTION

Tomatoes are the leading greenhouse vegetablecrop in the United States and Canada. In theU.S., the total acreage in greenhouse tomatoproduction increased by 40 percent between1996 and 1999. Statistics for 1999 show thatthe U.S. had about 800 acres in greenhousevegetable production, with tomatoes accountingfor 750 of those acres (1). The leading states ingreenhouse vegetable production are California,Florida, Colorado, Arizona, Ohio, Texas, andPennsylvania�each with more than one millionsquare feet in production (2). The vast majorityof greenhouse tomatoes are produced ingreenhouses using conventional productionsystems. Conventional and organic greenhouseproduction differ in the types of potting media,fertilization practices, and pest control methodsthey use.

EDUCATION IS KEY

Education is the first step toward a successfulgreenhouse tomato crop, and there is a lot of

Abstract: This publication offers an overview of organic greenhouse tomato production. To be successful, the small-scaleproducer needs to do thorough production and marketing research, find or create a niche market, and produce a consis-tently healthy crop. Maintaining optimum fertilization and moisture levels, practicing rigorous pest management, andensuring good pollination can increase crop yields. Information in this publication includes organic managementmethods for major diseases and insect pests; organic fertilization recommendations; a list of organic fertilizer suppliers;and a directory of further resources available on the Internet.

Special thanks to Dr. Elizabeth M. Lamb, VegetableExtension Specialist, University of Florida Instituteof Food and Agricultural Sciences, for reviewing thispublication.

Table of Contents

INTRODUCTION ............................................ 1EDUCATION IS KEY ..................................... 1MARKETING ................................................ 2SCHEDULING THE CROP .............................. 2SOIL AND SOILLESS MEDIA ........................ 3PEST MANAGEMENT ................................... 3RESISTANT VARIETIES ................................. 5NUTRITION .................................................. 6GROWER PROFILE ....................................... 7POLLINATION .............................................. 8SUMMARY ................................................... 8REFERENCES ................................................ 9RESOURCES ................................................. 9 ORGANIC FERTILIZER

DISTRIBUTORS ................................... 9 INFORMATION ON THE WEB .................. 10APPENDIX ONE ................................... 12-13APPENDIX TWO ......................................... 14

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 2

information available on growing greenhousetomatoes. Your local extension agent is an ex-cellent source of information for your area.Extension publications from all U.S. states areavailable on the Internet. Most publications canbe downloaded and printed at no charge. Cali-fornia, Colorado, Florida, North Carolina, Geor-gia, and Mississippi all have excellent informa-tion on growing greenhouse tomatoes. Dr. MaryPeet�s Greenhouse Vegetable Production Website isan especially good resource with links to manyrelated websites (see the Web Resources sectionfor the website address). This website offersvaluable information on sustainable productionand integrated pest management, with specificinformation on individual crops. MississippiState Extension Service has many publicationsand articles on greenhouse tomato productionwritten by Dr. Rick Snyder (see the Web Re-sources section for the website addresses). Thiswebsite focuses mainly on conventional green-house production; however, much of the infor-mation is valuable to both organic and conven-tional growers.

MARKETING

Sell your tomato crop before you plant it. It isimportant for small growers to explore nichemarkets such as selling directly to the public viaroadside stands or at farmers� markets. Mar-keting your products as �locally grown� is apossible strategy to explore. It may also be fea-sible to wholesale your product directly to localand regional retailers that sell organic produce.

Direct market sales are affected by competitionamong local greenhouses and by cut-rate whole-sale organic produce. The market can changerapidly, and greenhouse producers must beadaptable to change. The popular press andadvertising can have a powerful influence onconsumers. Niche markets can fade overnightwith the arrival of large wholesale operationsor simply by a change in consumer demand (3).For more information, request the ATTRA pub-lications Direct Marketing and Organic Market-ing Resources.

SCHEDULING THE CROP

Greenhouse tomatoes bring the highest pricefrom Decemberthrough April, whenit is too cool for lo-cal field-grown to-matoes. Wintergrowers maychoose between aone- or two crop system. With the one cropsystem, plants are set in September and growthrough the winter and spring until late June.This system works best in the cooler and lesshumid northern regions and is also used by mostFlorida growers. In a two-crop system, the fallcrop is succeeded by a spring crop. Tomatoplants that have been growing since Septemberdo not have the same vigor as the younger trans-plants. The older plants tend to have a densergrowth by winter, which reduces airflow andaggravates problems with humidity. Plants heldover winter are more likely to be infected withdiseases that thrive on high humidity and coolertemperatures, such as Gray Mold (caused byBotrytis cinerea) and Leaf Mold (caused by Cla-dosporium fulvum).

In a two crop system, the fall crop is seeded be-tween July and September. Check with yourlocal extension agent for planting times in yourarea. If the crop is planted too early, high sum-mer heat can stunt the young plants and delayharvest. For premium prices, try to schedulethe first harvest to coincide with the first frostin your area. In some southern states, first frostmay come as late as mid-November to early De-cember.

Seed the spring crop in mid- to late November.If possible, the seedlings should be started in aseparate house, in case there is a disease or in-sect problem with the fall crop. The seedlingswill be ready to transplant about six weeks af-ter seeding. Expect to see the first harvest inlate March or early April. The spring crop isusually grown until the summer crop of fieldtomatoes is ready to harvest.

Days to Maturity:Very Early 45-50Early 50-60Midseason 70-80

`

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 3

SOIL AND SOILLESS MEDIA

Greenhouse tomatoes can be grown in soil or insoilless media. In soil culture, crops are grownat ground level or in raised beds. The soil isusually amended with approved compost andother approved organic additives. The poten-tial for disease and nematode build up in or-ganic soil-based greenhouses is quite high inmany areas. Tomatoes, in particular, are vul-nerable to many soil-borne diseases, includingVerticillium and Fusarium wilts. Nematodes thatcan cause root knot galling can also be a prob-lem in some soils. Many growers go to the addedexpense of grafting onto disease and nematoderesistant rootstock. (Additional informationabout grafting is available at http://www.agnet.org/library/article/eb480.html#1.)Steam pasteurization and solarization in thesummer are approved pest control methods fornematodes, Verticilium, Fusarium, and other soil-borne pathogens.

Soilless cultivation methods�sometimes collec-tively (and loosely) known as hydroponics�arecovered in the ATTRA publications Greenhouseand Hydroponic Vegetable Resources on the Internetand Aquaponics: Integration of Hydroponics withAquaculture.

PEST MANAGEMENT

One key to a successful organic greenhouse op-eration is maintaining rigorous pest manage-ment. A pesticide-free greenhouse means thatgrowers must practice good sanitation and pestmanagement methods from the beginning.Pathogens or insects can become epidemic in agreenhouse environment in a very short time.

Once a pest problem has set in, there are fewoptions available to organic greenhouse produc-ers. For detailed information on specific green-house tomato pests and controls, see AppendixOne. Integrated Pest Management (IPM) is astrategy that can be used in organic productionas well as in conventional production systems.

IPM promotes a variety of tactics, including theuse of pest resistant varieties and biological,cultural, and physical controls. Pesticides are acontrol tactic used in IPM, but they are usedonly when needed. Pesticide use is thus mini-mized without jeopardizing crop quality oryield. Organic production systems use all ofthese, with the exception of chemical pesticides.Other pesticides, such as insecticidal soaps,biopesticides, botanicals, and mineral-basedpesticides, are allowed. For more detailed in-formation on greenhouse IPM, refer to theATTRA publication, Integrated Pest Managementfor Greenhouse Crops.

Cultural Control Methods

In a closed environment, some diseases can lit-erally spread overnight. Pathogens come in con-tact with the plants in many ways. Infested soilor plant debris, air movement, water, and con-taminated hands, tools, or clothing can allspread disease. Good ventilation and air circu-lation, rigorous sanitation practices, and main-taining optimum temperatures and humiditylevels are effective methods of disease controlin the greenhouse.

Sanitation

Rigorous sanitation practices are essential forhealthy and productive crops. Before a crop isplanted, it is important to thoroughly inspectthe greenhouse. Screens, doors, and wallsshould be checked periodically for any tears orother openings. Mulching around the plantsand using landscape fabric on walkways helpsto reduce weeds and soilborne pathogens. It isnot advisable to store houseplants in vegetableproduction greenhouses. A seemingly healthy

For general information about green-house organics, see the ATTRA pub-lication Organic Greenhouse VegetableProduction.

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 4

houseplant can be a vector for many diseasesthat attack vegetable crops (4).

During tomato production, debris and cull pilesare a prime source of many plant diseases.Promptly remove all plant debris from thegreenhouse areas before an infection can takeplace. Work surfaces should be made of non-porous material, such as stainless steel, and ster-ilized after each use. Laundry bleach is an ac-ceptable disinfectant, providing the residualchlorine levels in the bleach-water do not ex-ceed those set by the Safe Drinking Water Act(4 ppm).

Proper sterilization of hands, feet, and clothingwhen moving from house to house greatly re-duces cross-contamination. Before entering thegreenhouse, hands should be washed in hotsoapy water. For tobacco users (both smokersand chewers), a rinse of 1� 3% trisodium phos-phate prior to washing in hot soapy water isrecommended to avoid the introduction of To-bacco Mosaic Virus (TMV) into the greenhouse.Because TMV can survive on clothing for longperiods of time (up to 3 years in a darkenedcloset), it is important that clothing and over-alls be changed daily and washed and dried athigh temperatures. A shoe wash with a disin-fectant-soaked mat at the entrance to the green-house will help eliminate pathogens brought inon shoes. Adding a small enclosed entry porchto the greenhouse provides a place to decon-taminate shoes, tools, and equipment, and alsohelps keep out pests. In situations where thereis a contagious disease such as bacterial canker,all tools, machinery, and electromechanical pol-linators should be sterilized at the end of everyrow with ethanol or 0.5% sodium hypochlorite(5).

Ventilation, temperature control, andhumidity reduction

Temperature control and humidity reductionplay a major role in maintaining greenhousecrop health. During the fall, winter, and spring,when the majority of greenhouse tomatoes aregrown, high humidity and limited air circula-tion give many diseases an ideal growing envi-ronment. Moisture condensation creates humidconditions within the foliage, encouraging fun-gal and bacterial infection (6).

Good ventilation and proper temperature con-trol are critical for reducing humidity and con-trolling airborne fungal diseases. To ensure goodventilation, allow several feet of airspace abovethe plants and use proper spacing between them.Pruning the suckers just below the first fruit setalso helps to maintain good air circulationwithin the canopy. To increase ventilation, MikeCollins of Old Athens Farm in Westminster,Vermont, culls the bottom leaves once his plantsare four feet tall. Collins cuts the leaves off aninch away from the stem and snaps off the stubsat the next pruning to minimize Botrytis infec-tion sites (7). Some greenhouse producers also�lower� their crop�move the plants on theirsupports, so the sections ready for harvest arealways at the same level, enjoying the same tem-perature.

Good (Green)housekeeping

[ Keep doors closed and make sure allscreens are in good working order.

[ Make sure all plant debris and cullpiles are removed promptly.

[ Sanitize hands, tools, and machinerywhen moving from house to house.

[ Have a shoe wash at each entrance.[ Wash clothing regularly in hot water.[ Do not store houseplants in

production greenhouses.

©2002www.arttoday.com

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 5

Temperature control can be maintained inseveral ways. Polyethylene tubing works bestfor maintaining even temperatures throughoutthe greenhouse. With this system, fresh airfrom the outside can be warmed with fan-typeheaters to maintain optimum temperatures.Fans inside the greenhouse, mounted abovethe crop, help keep temperature uniform.With a pad and fan system, the air can be toocool at the cooling-pad end and too warm atthe fan end. Temperature differences of 10�15ºF can occur within the same greenhouse,which can cause catfacing, uneven growth,failures in fruit set, and devastating foliagedisease (6). And the higher the humidity, theless efficient evaporative systems are. For evenheating from the ground up, heating pipes canbe placed between alternating rows. Theheated air rises and pushes the cooler air tothe floor, helping to maintain good airflow.In hot climates, greenhouses need higher roofsto keep hot air away from the plants.

RESISTANT VARIETIES

Using disease-resistant seeds and transplantswhenever possible is one of the organic green-house producer�s best lines of defense. Forbest results, use good- quality seed from a repu-table source. Organic growers must use or-ganically grown seed if it is commerciallyavailable, or untreated seed from a conven-tional source if it is not. For a list of organicand untreated seed and transplant suppliers,see ATTRA�s Suppliers of Organic and/or Non-GE Seeds and Plants.

Optimum air temperature forsustained tomato growth:

Day: 75�85°F

Night: 60�70°F

To indicate disease resistance, a series of abbre-viations is usually listed with the description ofthe cultivar. Each abbreviation stands for a spe-cific pathogen. For instance, Tobacco MosaicVirus is TMV; Fusarium Wilt race 1 is F1, etc.(8). Fusarium Crown and Root Rot may beprinted as FCRR or FrWi depending on the dis-tributor. See Table 1 for examples of majorgreenhouse tomato diseases and their abbrevia-tions. See Table 2 for a list of resistant green-house tomato varieties.

Once a variety of tomato has been selected, thenext task is to decide whether to grow trans-plants from seed or to purchase plugs. Eitherway, all transplants must be grown using ap-proved organic methods and inputs. The ad-vantages of producing plugs in-house includean efficient use of greenhouse space and rapidproduction. The disadvantages include extralabor cost for seeding and transplant produc-tion and increased heating costs in winter (plugs

Table 1. Common DiseaseAbbreviations*.

Disease AbbreviationBacterial Speck BSK-OEarly Blight (Alternaria) EBFusarium Crown & Root Rot FCRR or FrWiVerticilium Wilt Race 1 VFusarium Wilt Race 1 F1 Race 2 F2 Race 3 F3Leaf Mold (Cladosporium) C2, C5, C7Nematode NPowdery Mildew (Oidium) OiGray Leaf Spot (Stemphylium) StTobacco Mosaic Virus TMVTomato Spotted Wilt TSW or TmSwTomato Mosaic Virus ToMV*These are examples of common abbreviations. Suppliers maydiffer in abbreviation styles.

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 6

are very sensitive to temperature fluctuations).There are many issues to consider when decid-ing whether to use seed or transplants. The sizeof the operation, available labor, and cost ofproduction are just a few considerations. Ac-cording to Kessler and Behe (9):

The decision should be based partially onmarket considerations, labor availability andexpertise, the number of plants to be pro-duced, the cost per plug, and the special-ized equipment and facilities required. Thisinvestment is often not economically practi-cal unless production is large or plugs aremarketed to other growers. For most smallto medium sized growers, especially [begin-ners], it is often more economical topurchase�plugs from specialized growersand concentrate on producing finished con-tainers. The issue of grow versus purchaseshould be reviewed periodically as the needsand facilities of the grower change.

For more-detailed information on plug produc-tion, see the ATTRA publication Organic Plugand Transplant Production.

NUTRITION

A well-fed plant is a healthy plant. Maintain-ing optimum nutrient, light, and moisture levels will result in healthier plants that are betterable to fend off diseases and insect pests. To-matoes are heavy feeders because of their rapidgrowth and long production season. Tomatoesneed 75 to 100 pounds of nitrogen (N) per acreand moderate to high levels of phosphorus (P)and potassium (K) for maximum yields. Soiltests can establish what nutrients soil needs.Some growers add a mixture of animal meal by-products, rock phosphate, and kelp meal to pro-vide needed nutrients. Fertilizer efficiency ishighest at a pH of 6.0 to 6.8. To help maintainproper nutrition and pH levels, a pH meter is ahandy tool. For more information on organicfertilizers and the nutritional needs of tomatoes,see the ATTRA publication, Organic Tomato Pro-duction.

According to the National Organic Standards,it appears that organic greenhouse crops maybe grown either in soil or in soilless media. Build-

Table 2. Disease-resistant Greenhouse Tomato Varieties*.

Disease Resistant Varieties Tolerant Varieties

Fusarium Crown and Root Rot TrustFusarium Wilt Race 1 Caruso, Trust Vendor Race 2 Caruso, Trust Vendor Race 3Leaf Mold (Cladosporium) Buffalo, Capello, Caruso (races A thru E), Cobra, Dombito, Jumbo, Match, Pink KR15 and Pink CR-864 with gene Cf-5, Trend, Trust (races

A thru E), Ultra Sweet & Ultra Pinkwith Cf-7, Vision, Furon andVetomold with Cf-2

Powdery Mildew (Oidium) DRW 4409, Belliro (DRW 4369) Grace, MilanoGray Leaf Spot (Stemphylium)Tobacco Mosaic Virus Boa, Caruso, Cobra, Trust VendorTomato Spotted Wilt DRW 5719

*Remember, you must use organically grown seed if it is available commercially, or untreated seed if it is not.

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 7

ing nutrient-rich soil in a greenhouse environ-ment takes extra time and effort, but the resultsare well worth it. Compost is the main nutrientingredient used in soil beds. One grower inCanada applies compost at a rate of one or twocubic meters per 100 square meters of bed space(1.2 to 2.4 cubic yards per 1,000 square feet).The beds are then covered with straw mulch.Five to six applications were added to the bedsat five- to six-week intervals in the first year.The compost was applied in smaller amountsand less frequently through the fourth year. Arich, healthy soil was the result. Soil organicmatter usually ranges from 10 to 12% and can

even reach a remarkable 25 to 30% after sev-eral years. For more information on large-scalecomposting, see ATTRA�s Farm-Scale CompostingResource List.

Soilless technology shows promise for increas-ing yields and reducing economic losses to soil-borne diseases. Dr. Mary Peet and Janet Milesof North Carolina State University have recentlyconcluded a study to develop organic fertiliza-tion regimes specifically for greenhouse toma-toes using soilless media. See Appendix Twofor a copy of the article, �Recommended Fertili-zation Practices for Producing Organic Green-

GROWER PROFILE

Six years ago, Mike Duda, a market gardener from Victor, Montana, was just sick about histomatoes: The high winds and cool nights around Victor were costing him two-thirds of hiscrop. That was when he decided to try greenhouse production. He bought a 30� x 90� metal-frame greenhouse kit, erected it himself, and installed an inflateable poly cover. A second-handoil-fired funace supplied the heat. An old attic fan furnished ventilation exhaust, and someused house fans moved air around inside the greenhouse. And not much has changed sincethen, except that Mike�s tomato harvest has tripled.

Duda grows in soil, on raised beds. As he describes it: �We live in cattle country, so manure iseasy to find. I use aged (three years) cow manure about two inches deep, dolimite lime, rockphosphate, and a little homemade wood ash. I use a soil test to gauge the amounts and hand-dig the beds. . . . I also fertilize with seabird guano every couple of weeks. I use drip tape forirrigation and tie the tomatoes to twine attached to the greenhouse for support.

�I start the tomatoes from seed on December 26. . . . Harvest starts the last week in May andcontinues through October. It peaks mid-June to mid-August, when we get 250 pounds a week.

�I use garden variety tomatoes, not greenhouse varieties. They�re bred for shipping, not taste. Iuse Brandywine with good results, Oregon Spring with excellent results (they don�t need pol-lination), and Sungold with excellent results (they produce until Thanksgiving).

�I spray with kelp weekly until the fruit set. It works well. You eventually get some disease, butit�s near the end of the crop, so you tolerate it as long as you can, then remove [the diseasedplants]. We do see a few aphids. I use soap spray when they get too bad. This year I�m going totry some beneficial insects; it�s hard to spray effectively when the plants are big.

�We sell all of our tomatoes at the farmers� market, all at retail prices. It�s good for us, and thecustomers love fresh tomatoes. This will be our sixth year for greenhouse tomatoes, and I can�timagine not having them. It�s fun to be able to start gardening in the middle of winter, andtomatoes always sell well.�

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 8

house Tomatoes� by Janet Miles. This articleincludes detailed recipes for each stage of ma-turity.

POLLINATION

Tomato plants have both male and female re-productive organs on the same flower, so witha little help, each flower can self-pollinate. Inthe natural environment, wind and insects pol-linate tomatoes. In a greenhouse environment,more attention must be paid to the pollinationprocess to ensure maximum fruit set. Today,tomatoes are pollinated in greenhouses eitherby bumblebees or by mechanical pollinators.

Mechanical pollination is done with a battery-powered, hand-held pollinator or by electricvibrating benches. The hand-held pollinatorsare labor-intensive. Workers have to hand pol-linate each plant two or three days each weekduring flowering. Vibration benches work onan automatic timer and do not require muchlabor after installation, but they are expensiveand not cost-effective for small- to medium-scalegrowers.

Mechanical pollination of tomatoes was pre-dominant in U.S. and Canadian greenhousesuntil the mid-90s, when the use of bumblebeeswas adopted from European growers. Today,most greenhouse tomato growers in NorthAmerica are using bumblebees, which workevery day of the week, selecting only the flow-ers that are ready to pollinate. Bumblebees canpollinate up to 30 flowers a minute. It is notunusual to have 100% pollination, which resultsin higher yields than are achieved with me-chanical methods (10).

Bumblebees are mild-mannered and easy towork with; they rarely sting without provoca-tion. They start a new colony each year, withonly a single queen hibernating over the win-ter. This queen then starts a new colony in thespring. By mid-summer the colony can num-ber in the hundreds. At the end of the summer

the bees begin to die out and the process startsover again. However, due to breakthroughs inbumblebee breeding, full-strength colonies ofbumblebees are now available year round.

For commercial production, the bees are shippedby airfreight and placed in the greenhouse asthe first flowers begin to open. Stocking ratevaries from one hive for a small greenhouse totwo to four hives per acre for larger facilities.The hives are usually replaced every 8 to 12weeks as the colony begins to die out. Thereare two primary species of bees produced inCanada and the United States: Bombusoccidentalis for the west and B. impatiens for theeast. According to the USDA and AgCanada,the dividing line is at the 100th meridian, whichruns through the middle of Texas, Oklahoma,Kansas, Nebraska, and the Dakotas. To avoidconfusion, the USDA has classified these statesas �eastern� states in the case of bees. BeesWest, Inc., supplies western species, andKoppert Biological Systems, Inc., supplies east-ern species (10).

SUMMARY

A successful organic greenhouse tomato opera-tion will require research into all aspects of thebusiness. Before planting the first seed, it is im-portant to locate a niche market in your areaand schedule harvests to coincide with times ofhigh market value. Soil systems have manyadvantages compared to soilless systems; how-ever, they can be sources for soil-borne diseasessuch as Verticilium and Fusarium wilts. Main-taining rigorous pest control is key to maintain-ing a healthy, productive greenhouse operation.Successful pest control includes incorporatingIntegrated Pest Management practices, includ-ing cultural control methods, and the plantingof disease resistant varieties. Organically grownseed must be used if available. If not, commer-cially available untreated seed may be used. Alltransplants, whether purchased or grown onthe farm, must be grown using approved or-ganic methods and inputs. Maintaining proper

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 9

pH and fertilization levels improves disease re-sistance and increases yields. Using bumblebeesfor pollination can also increase yields and re-duce labor costs.

REFERENCES

1) Snyder, Richard G. 1995. GreenhouseTomatoes�The Basics of SuccessfulProduction. Proceedings of the Green-house Tomato Seminar. August 3-4,1995. Montreal, Quebec, Canada.

2) Census of Agriculture. 1997. U.S. Cen-sus of Horticulture Specialties. Bureauof the Census, U.S. Department of Com-merce, Washington, D.C.

3) Snyder, Rick. No date. GreenhouseTomato Handbook. Mississippi State Ex-tension Service.<http://msucares.com/pubs/pub1828.htm>.

4) Dr. Craig Anderson, Horticulture Exten-sion Specialist, University of Arkansas,Personal communication, June 2001.

5) Jarvis, William R. 1992. Managing Dis-eases in Greenhouse Crops. The Ameri-can Phytopathological Society, St. Paul,Minnesota. p. 148�149.

6) Wittwer, S. and S. Honma. 1979. Green-house Tomatoes, Lettuce & Cucumbers.Michigan State University Press, EastLansing. p. 72.

7) Grubinger, Vernon P. 1999. SustainableVegetable Production from Start-up toMarket. NARES. New York, New York.p. 229�233.

8) Sanders, Doug. 1999. The Perfect Vari-ety. American Vegetable Grower. Vol.47, No. 12. p. 47-48.

9) Kessler, J. and Bridget Behe. 1998. Pro-duction and Marketing. ANR-596. Ala-

bama Cooperative Extension.<http://www.aces.edu/department/extcomm/publications/anr/anr-596/anr-596.htm>. 16 p.

10) Kueneman, Tom. 1995. The pollinator.Greenhouse Product News. Vol. 5, No.9. p. 8, 10.

RESOURCES

Organic Fertilizer Distributors

Agri-Growth International, Inc.http://www.agriorganics.com

Agri-Growth International, Inc. is a manufac-turer of organic plant nutrients and stimula-tors. This website offers information on theirproducts.Send e-mail to herb@agriorganics.com,or contact them at 1-780-484-0102 for a dis-tributor listing in your area.

Alternative Garden Supplyhttp://www.alternativegarden.com/

Alternative Garden Supply offers a completeonline store and a listing of retailers in your area.They carry a variety of liquid organic fertilizerssuch as Earth Juice, Fox Farm, Pure Blend,Maxicrop, and Age Old Organics.

Atlantis Hydroponics1035 Baxter StreetAthens, GA 30603(706) 543-9980Toll Free: (888) 305-4450Fax: (706) 543-9919info@atlantishydroponics.comhttp://www.atlantishydroponics.com

Atlantis Hydroponics offers a wide range of or-ganic fertilizers and stimulants: Alaska Start-up, Earth Juice, Fox Farm, Neptune�s Harvest,Pure Blend, and others.

Greenfire347 Nord Ave. #1Chico, CA 95926(916) 895-8301Fax: (916) 895-8317http://www.greenfire.net/

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 10

Greenfire offers a wide range of organic fertiliz-ers for both soil and soilless media. Greenfireis an Earth Juice distributor.

Growlight.comsales@growlight.comhttp://www.growlight.com/

Online catalog with a distributor list for retail-ers in your area. Organic products includeB�Cuzz Growth, Root, and Bloom Stimulators;Nitrozime; and Age Old Organics Liquid Grow,Bloom, and Kelp.

Harvest Moon Hydroponicshttp://www.hmoonhydro.com/

Harvest Moon Hydroponics offers a completeonline store with a wide range of organic fertil-izers and stimulants: including B�Cuzz, EarthJuice, Pure Blend, Superthrive, Nitron A-35,Grow Big, and Big Bloom. The website includesa list of Harvest Moon retailers in your area.

Home Harvest® Garden Supply, Inc.3807 Bank StreetBaltimore, Maryland 212241-800-348-4769Voice: (410) 327-8403Fax: (410) 327-8411ugrow@homeharvest.comhttp://homeharvest.com/storeinfo.htm

Earth Juice, Fox Farm, and others.

HydroMall�http://www.hydromall.com/infocart/Organic_Fertilizer/

HydroMall� offers organic fertilizers fromAgri-Growth International, Inc., such as:Myco-Net Biological Inoculum, Nutri-Max, andothers. Order online from HydroMall� or seetheir Stores Directory for a retail store near you.

Information on the Web

Budget for Greenhouse TomatoesMississippi State University, Cooperative Exten-sion Servicehttp://msucares.com/pubs/p2257.html

Commercial Greenhouse Tomato ProductionColorado State University; Cooperative Exten-sion Servicehttp://www.ext.colostate.edu/pubs/gar-den/07606.pdf

Dr. Mary Peet�s Greenhouse Vegetable Pro-duction WebsiteNorth Carolina State Universityhttp://www.ces.ncsu.edu/depts/hort/greenhouse_veg/resources/

Resource page with links to conversion tools,print information, and related Websites.

Environmental Control for GreenhouseTomatoesMississippi State University, Cooperative Exten-sion Servicehttp://msucares.com/pubs/pub1879.htm

Florida Greenhouse DesignUniversity of Florida, Cooperative ExtensionServicehttp://edis.ifas.ufl.edu/scripts/htmlgen.exe?DOCUMENT_AE016

Grafting, De Ruiter Seeds Inc.http://www.deruiterusa.com/guide.html

(Guidelines for Grafting)http://www.deruiterusa.com/root.html

(Rootstock Germination)

Greenhouse Tomato HandbookMississippi State University, Cooperative Exten-sion Servicehttp://msucares.com/pubs/pub1828.htm

Greenhouse Tomato ProductionOregon State University, College of AgriculturalScienceshttp://www.orst.edu/Dept/NWREC/tomatogh.html

Growing Hydroponic TomatoesThe University of Arizona, College of Agricul-turehttp://ag.arizona.edu/hydroponictomatoes/index.htm

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 11

Insect and Disease Problems of TomatoTexas A&M University, Aggie Horticulturehttp://aggie-horticulture.tamu.edu/imagemap/mgmaps/mgprob.html

North Carolina State�s Greenhouse Food Pro-duction WebsiteNorth Carolina State Universityhttp://www.ces.ncsu.edu/depts/hort/greenhouse_veg/index.htm

Topics include culltural control, biological con-trol, and organic production.

Single Truss Tomato Production SystemBioresource Engineering DepartmentRutgers University - Cook College, New Jerseyhttp://nj-nscort.rutgers.edu/visitor/tps/index.html

Starting A Greenhouse BusinessMississippi State University, Cooperative Exten-sion Servicehttp://msucares.com/pubs/pub1957.htm

Starting Vegetable TransplantsMississippi State University, Cooperative Exten-sion Servicehttp://msucares.com/pubs/pub1995.htm

Texas Greenhouse Management HandbookTexas A&M University, Aggie Horticulturehttp://aggie-horticulture.tamu.edu/green-house/guides/green/green.html

Tomato Plant Problems FAQ, by Kay Klierhttp://is.rice.edu/~shel/tomato.html

An overview of tomato plant problems and or-ganic cures.

By Mardi Dodson, Janet Bachmann,and Paul WilliamsNCAT Agriculture Specialists

Edited by Richard EarlesFormatted by Cynthia Arnold

March 2002

IP 190

The electronic version of Organic Greenhouse TomatoProduction is located at:HTMLhttp://www.attra.org/attra-pub/ghtomato.htmlPDFhttp://www.attra.org/attra-pub/PDF/ghtomato.pdf

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 12

PROBLEMS IN THE GREENHOUSE

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APPENDIX ONE

PROBLEMS IN THE GREENHOUSE

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 13

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//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 14

APPENDIX TWO

RECOMMENDED FERTILIZATION

PRACTICES FOR PRODUCING ORGANIC

GREENHOUSE TOMATOES

BY JANET MILES

Janet Miles developed these recommendationsas part of an M.S. thesis under the supervisionof Dr. Mary Peet. The thesis is entitled: Organic,Biorational and Conventional Growing Systemsfor Greenhouse Tomatoes, 2000, North Caro-lina State University, Raleigh, NC.

For more information on this study and on organic production, visit the North CarolinaGreenhouse Food Production website:<http://www.ces.ncsu.edu/greenhouse_veg/>.

These recommendations were devised fromstudies performed on �Grace� tomatoes�a vari-ety bred specifically for greenhouse production,grown in 5 gallon upright plastic bags with soil-less substrates in polyethylene greenhouses.

For current requirements for organically certi-fied greenhouse vegetable production, consultthe National Organic Program website <http://www.ams.usda.gov/nop/>. Draft recom-mendations for greenhouses are available at:<http:/www.ams.usda.gov/nop/nop2000/nosb/recommedations/Crops recommenda-tions/greenhouse.pdf>. For additional com-mercial materials which may be allowable fororganic growers, consult the Organic MaterialReview Institute website<http://www.omri.org/>.A list of suppliers of organic fertilizers and hor-ticultural substrates is available from ATTRA<http://www.attra.org/>.

This study was begun in 1998, before the initia-tion of national standards and with few poten-tially certifiable materials available. It can beused as a guideline for selecting and using or-ganic fertilizers for greenhouse tomato produc-tion, but growers are advised to check theATTRA and OMRI sites for new materials andwith their certifying agency to see if particularmaterials are allowable.

Transplant Production:

1) Seeds: 4-7 days until first true leavesappeara) sow in sterile seedling mixb) Place seed trays in a mist bed

with bottom heati) Temperature: 75-80°F

ii) 16 hours fluorescent light

2) Transplant Seedlings: 4-6 weeks depend- ing on Fall or Spring crop a) 4� pots with peat or coir-based

substrate*note: We used a special mixprovided by Faford which is equivalentto their commercial 4-P, but withoutthe starter nutrient charge or wettingagent, which would not be acceptablefor organic certification. (See SubstrateRecipe in the Greenhouse Productionsection).

b) Nutrients:i) Constant feed of fertilizer/water

solutionii) Earth Juice� brand: This

product is comprised of threedifferent formulations. Theyalso have a source of K2O and asource of micronutrients.Grow: analysis 2-1-1. Ingredi-ents: bat guano, NorwegianSea Kelp, natural sulfate ofpotash, feather meal, oat bran,blood meal, and steamed bonemeal.Bloom: analysis 0-3-1. Ingredients: bat guano, Chilean seabird guano, Norwegian SeaKelp, natural sulfate of potash,steamed bone meal, oat bran,and rock phosphate.Catalyst: analysis 0.03-0.01-0.10. Ingredients: oat bran,kelp, wheat malt, molasses,and yeast.

Earth Juice RecipeMixed in 2 gal. water for directfertilization:(Not concentrated for injectors)3 tbsp. Bloom

//ORGANIC GREENHOUSE TOMATO PRODUCTION PAGE 15

3 tbsp. Catalyst5 tbsp. Grow2 tbsp. K2O* To provide 90 ppm N, 45 ppmP, and 195 ppm K.

iii) Magna Gro� brand:HydroponicBase Mix analysis2-3-6. Ingredi ents: poultrycompost tea, pasteurized bloodmeal, calcium phosphate, andseaweed. This also containstrace minerals withfermented molasses in theform of Zn SO4, Mg SO4, andFe SO4. 19% N frompoultry compost tea andpasteurized blood meal. K-9:9% K2O from seaweed. Or-ganic forms of trace mineralssupplied as 6% B, 6% Fe, 6%Mg, and 6% Ca.

Magna Gro RecipeMixed in 2 gal. water for directfertilization:(Not concentrated for injectors) 2 tbsp. Hydroponic Base Mix 1/8 tsp. 19% N 1/3 tsp. 9% K*To provide 90 ppm N, 45 ppmP, and 195 ppm K.

Greenhouse Production:

1) Transplant when seedlings have 5-7true leaves�BEFORE any flowershave opened.

2) 5 gal. plastic �grow bags� filled withpeat or coir-based substrate that hasnot been amended with a starternutrient charge or wetting agent, asthese products are most likely frominorganic sources and not acceptablefor use in organic production. Weblended our own mix fromcommercial blend specially formulatedto omit the wetting agent and startercharge.

� 85% Fafard�s Special OrganicMix1: Ingredients: Canadiansphagnum peat moss,vermiculite, perlite, gypsum,dolomitic lime, pine bark

� 15% Vermicycle (commercialworm compost)

� J.H. Biotech2 �Natural Wet� 2T./ gal.� 1.25 lbs./cu.yd. each, blood meal, bone meal, and potassium sulfate� ½ lb/cu. yd. elemental sulfur

Several commercial organic mixes are nowavailable, but were not tested in this project.Sun Gro Horticulture, Inc., has a retail andprofessional line of soilless mixes which isOMRI approved. They can be used for trans-planting or in containers. Sun Gro producesretail potting mixes under the Sunshine andother brands (Phone 888-896-1222). McEnroeOrganic Farm, 194 Coleman Station Road,Millertown, NY 12546 (518-789-3252) offersboth a light growing mix and a potting soil,which they suggest combining with vermicu-lite for a seed starting mix. You can also searchfor organic and OMRI-certified supplies atPeaceful Valley Farm Supply (http://www.groworganic.com/).

3) Nutrition:*Note�Stage 1 = From transplant to thefirst fruit setStage 2 = From first fruit set to�topping� the plants�when theyare about 6� tallStage 3 = From topping to the endof the cropa) Fertigation using ½ gph emitters is

ideal:Stage 1: 6 minutes/cycle, 4 cycles/day, to supply 0.89 liters/plant/dayStage 2: 8 minutes/cycle, 4 cycles/day, to supply 1.20 liters/plant/dayStage 3: 13 minutes/cycle, 4 cycles/day to supply 1.77 liters/plant/day

b) Commercial fertilizers should be for-

1Fafard�s Special Organic Mixture: Contact Hugh Poole, Fafard, 6406 Carmel Road, Suite 30, Charlotte, NC 28226, SC29622 Phone: 1-800-845-1664 or 1-800-722-7645 email: sales@fafard.com; http://www.Fafard.com/

2Wetting agent: Harold Uradomo, 805-650-8942, J.H. Biotech, Inc., 4951 Olivas Park Drive, Ventura, California 93003

//ORGANIC GREENHOUSE TOMATO PRODUCTIONPAGE 16

mulated to provide the followingN-P-K concentrations:

Stage 1 Stage 2 Stage 390 ppm N 125 ppm N 165 ppm N45 ppm P 45 ppm P 45 ppm P195 ppm K 195 ppm K 310 ppm K

i) Earth Juice�. In addition to productslisted under the Organic Transplant Pro-duction section, they also have a pro-duct called:�Microburst Three��derived from sul-fates of Magnesium, Cupric, FerrousManganese, Zinc, Borate, and Kelp toprovide micronutrients. K2O is a 10% Ksource.

Recipe�Earth Juice�: Stage 1To make 1 gal. of stock to be injected at a rate of 50:1

1 qt. Grow1 qt. Catalyst2 c. Bloom1½ c. 10% K2O

Recipe�Earth Juice�: Stage 2 To make 1 gal. of stock to be injected at

a rate of 50:11 qt. + 1¼ c. Grow1 qt. + 1¼ c. Catalyst1¼ c. Bloom1¼ c. 10% K2O½ c. Microburst Three

Recipe�Earth Juice�: Stage 3 To make 1 gal. of stock to be injected at

a rate of 50:11 qt. + 3 c. Grow1 qt. + 3 c. Catalyst¾ c. Bloom2¼ c. 10% K2O½ c. Microburst Three

ii) Magna Gro�Recipe for Magna Gro�: Stage 1

To make 1 gal. of stock to be injected at a rate of 50:1

1 qt. + ¼ c. HydroponicBase Mix (HBM)½ Tbsp. 19% N¼ c. 9% K

Recipe for Magna Gro�: Stage 2 To make 1 gal. of stock to be injected at

a rate of 50:11 qt. + ¼ c. HydroponicBase Mix (HBM)1/3 c. 19% N¼ c. 9% K

Recipe for Magna Gro�: Stage 3 To make 1 gal. of stock to be injected

at a rate of 50:11 qt. + ¼ c. HydroponicBase Mix (HBM)1 c. 19% N2 c. 9% K

c) The start-up nutrient charge that wasadded to the growing medium will pro-vide enough nutrients to last 2-3 weeksafter transplanting. At this time, plantswill probably have progressed to Stage2 of development.