Tomatoes are the most abundantly produced greenhouse vegetable crop in the United States. The use of compost substrates has increased in recent years for the greenhouse production of many vegetables, bedding plants, and nursery crops. `Blitz' tomatoes were grown during the spring and fall growing seasons in 2004 in six substrate blends of pine bark (PB), a traditional production substrate in the Southeastern U.S., and cotton gin compost (CGC), an agricultural by-product, to assess the potential use of CGC as a viable replacement for PB for the production of greenhouse tomatoes. Treatments ranged from 100% PB to 100% CGC. During both growing seasons, plants grown in substrates containing CGC produced similar total, marketable, and cull yields compared to plants grown in 100% PB. Substrates containing 40% or more CGC had significantly higher EC levels both initially and throughout both growing seasons than did 20% CGC and 100% PB blends. Initial and final pH of all substrates was similar during both studies and remained within recommended ranges for greenhouse tomato production. Water-holding capacity increased as the percent CGC increased in each substrate blend, indicating the need for less irrigation volume for substrates containing CGC compared to the 100% PB control. Results indicate that CGC can be used as an amendment to or replacement for PB in greenhouse tomato production.
Brian E. Jackson, Joe M. Kemble, Amy N. Wright, and Jeff L. Sibley
Richard Snyder*, David Ingram, Blake Layton, Ken Hood, Mary Peet, Mary Donnell, Gene Giacomelli, Joe Kemble, Pat Harris, and Frank Killebrew
The Mississippi (MS) Greenhouse Tomato Short Course has been held every March since 1989. The purpose of this 2-day, intensive training is to educate growers so they will be able to successfully grow greenhouse tomatoes as a viable horticultural business. With a mixture of experienced, novice, and prospective growers, it is just as important to provide current growers with research based, practical information, as to expose potential growers to the realities of the business, helping them make an informed decision before investing time and money. Beginning as a small program for a handful growers in the conference room at the Truck Crops Experiment Station, it has gradually grown in number and diversity of participants and invited speakers, depth of subject matter, and geographic origin of growers and speakers. The 2003 program had 142 participants from over 20 states and 4 countries, making it the largest such program in the United States. This is in keeping with the recent trend. The typical lineup of topics includes the basics of producing a commercial crop of hydroponic greenhouse tomatoes, the budget for establishing and operating a greenhouse business, marketing and promotion, pest and disease identification and management, and the grower's point of view. Other topics, varying year to year, include heating, cooling, and ventilation of greenhouses, record keeping, new technologies, biological control, diagnostics, and alternative crops. For 2004, the subject of organic production will be introduced. With targeted extension programming such as this Short Course, the greenhouse tomato industry in MS has grown from 15 growers in 1989 to 135 growers today, producing $6.5 million in annual gross sales. Complete information can be found at www.msstate.edu/dept/cmrec/ghsc.htm.