Garden Tips: Starting Transplants Indoors

March is a good month for starting "transplants" for moving into the garden in late April or early May. Transplants are also known as 'bedding plants' when sold in nurseries and garden centers. If you would like to grow your own plants from seeds, begin by finding a suitable location in the home where plants grow well. Seedlings must have bright light. Therefore, a south-facing window with little shade from overhangs, trees, or other buildings is best. When there is no windows that provide adequate light, supplement existing window light with artificial light.

Fluorescent tubes make an excellent additional light source. They should be placed about 6 inches from the tops of seedlings, and run for about 12 hours each day. In combination with outdoor light, run the artificial lights at the same time. If artificial lights are used where there is no outside light, the lights should be kept running for at least 16 to 18 hours each day. In addition to having bright light, seeds should be sown in a fine, artificial growing media, or a loose, welldrained soil mix that has been sterilized.

Several disease organisms can be carried in soil that will attack young seedlings. These diseases may kill seedlings before they emerge from the soil, but if they attack the plants after they are above the soil, the problem is called "damping-off." Even though purchased seedling mixes should be sterile, added safety can be achieved by placing the pots or flats filled with any moist seedling mix into an oven for sterilization. An oven should be set no lower than 140 degrees and no higher than 200 degrees for best sterilization.

Cover the trays or pots with foil to keep them moist during heating. Make sure that the medium in the containers is completely cooled before planting seeds. Except for a few cool season crops, most seeds germinate best at temperatures between 70 to 75 degrees. After the seedlings begin to emerge, temperatures between 55 and 60 degrees are usually high enough for good growth. Plants grown too warm become tall, thin, and weak.

If few plants are needed, and your time is limited, direct seeding into individual pots can save time and labor by eliminating a later need for transplanting seedlings from the flat into individual pots. Three seeds placed in each pot can later be thinned to one if needed. Direct seeding also speeds growth since it eliminates transplanting delay sometimes called "transplant shock."

Very fine seeds do not need to be covered, and may be scattered on the surface, while larger seeds need light covering. After seeding, cover containers with plastic or glass to keep the surface moist and allow some light penetration. Remove the coverings as soon as seedlings begin to appear. The seedling media should be thoroughly moist before planting. If it is, there will be no need to water until after seeds have germinated, provided containers have been properly covered.

In addition to clay, plastic, or peat pots, many household containers, such as paper cups, plastic food containers, or egg cartons, can be adapted for seed germination. Whatever container is used, make sure that it has adequate holes in the bottom for good drainage.

Accessible Gardening: Tips & Techniques by Joan Woy.