Chapter 1: Vegetable Production Recommendations
Flats,Trays, and Pots Use new flats and liners for transplant production to avoid pathogens that cause damping-off and other diseases. If old trays or liners are used, they should be thoroughly cleaned. Dip them in 10% chlorine bleach several times, then cover with plastic to keep them wet overnight. The bleach solution should remain below pH 6.8 to effectively kill disease pathogens (make a new bleach solution every 2 hours or whenever it becomes contaminated or diluted). Wash the trays with clean water to eliminate the chlorine, and let the flats dry prior to use. Wash exposed surfaces
like benches, frames, and walls in the greenhouse to sterilize them as well. If plastic pots are reused, disinfest them as described above.
Seedling performance depends on cell size. Generally, transplants grown in larger cells (50’s, 72’s) produce earlier yields. Cell size does not affect total yield when growing seasons are long. If earliness is important, use larger cell sizes or bigger pots. While you may grow more plants per unit area of greenhouse in small cells (128’s, 256’s) and keep costs down, these trays may not be appropriate for some vegetables like melons. Transplant production cost depends on the number of plants grown per unit area and the length of time needed to grow the plant to plantable size.
Plant-Growing Mixes
There are many different pre-mixed growing media available and the best are lightweight, disease-free, and made from peat and vermiculite. Most commercial mixes produce quality transplants when used with good management practices. Commercial mixes can vary in composition, particle size, pH, aeration, nutrient content, and water-holding capacity. Most growers find a mix that works well for them and then continue to use it year after year. Avoid fine particle
Table 1.2. Transplant mixes for pots, flats, or transplants trays. Tipi Potting Mix Recipe (organic) 2 bales sphagnum peat moss (3.8 or 4.0 cubic foot bales) 1 bag coarse vermiculite (4.0 cubic foot bags) 1 bag coarse perlite (4.0 cubic foot bags) 6 quarts of a fertilizing mix comprised of: 15 parts steamed bone meal 10 parts kelp meal 10 parts blood meal 5 to 10 parts dolomitic limestone (80 to 90 mesh)
Standard Vegetable Transplant Mix Equal parts by volume of: • Vermiculite • Peat moss • Perlite (use common liquid feeding program after seedlings emerge)
Organic Potting Mix 1 part sphagnum peat 1 part peat humus (short fiber) 1 part compost 1 part sharp sand (builder’s) To every 80 quarts of this add: 1 cup greensand 1 cup colloidal phosphate 1½ to 2 cups crab meal or blood meal ½ cup lime
Organic Soil Blocking Mix 3 buckets (10-quart bucket) brown peat 1/2 cup lime (mix well) 2 buckets coarse sand or perlite 3 cups base fertilizer (mix equal parts blood meal, colloidal phosphate, and greensand together) 1 bucket good garden soil 2 buckets quality compost Mix all components thoroughly and moisten to point where blocks hold together.
Utah Vegetable Production and Pest Management Guide
3
Production
High quality transplants are almost always grown in heated greenhouses where growing conditions are carefully managed. To grow quality transplants, it is important to optimize inputs like growing media, temperature, fertilization, water, and spacing needs. Table 1.1 provides seed spacing and temperatures for seed germination and plant growing, and the time required to grow the plant to transplantable size. Quality plants are grown by using the appropriate trays and soil media, controlling germination, temperature and nutrients, and properly conditioning the plants for the field.