Starting seed indoors enables gardeners to select the exact varieties they want for vegetable or flower beds, whether an heirloom tomato or new zinnia variety. There are other benefits from having a variety of home-grown vegetables and flowers. One of the most satisfying is to say, “I grew these plants myself, from seed.”
Vegetable seeds that are easy to start indoors include tomatoes, peppers, squash, cabbage, eggplant and cucumber. Marigold and zinnia flower seed also are simple to start inside.
Garden centers and mail-order catalogs offer many varieties from the newest and improved ones to favorite standbys. To avoid buying too many seed, calculate how many plants of each variety are needed for the garden.
For greater success starting seed indoors, don’t plant them too early and give them adequate, but not excessive, water and sufficient light.
Seed planted too early result in overgrown plants that are yellow, crooked and spindly before it is even time to transplant them outdoors. Thus, it is critical to properly time the planting of new seed so young seedlings will be large enough to transplant in the garden when the danger of a late frost is over.
To determine when to start the seed, check the outdoor sowing time on the seed packet or last late frost date for your location. Plant seeds three to four weeks prior to the recommended seed packet date, or time for the last late frost. An exception is squash and cucumbers, which require only seven to 10 days for seedlings to grow large enough for transplanting in the garden.
When it’s time to plant seed, gently press potting soil into each small container; add two seed per container at the depth recommended on the package, and put the containers in leak-proof trays. Unless you are using a peat product, be sure containers have at least one drainage hole.
Then, slowly water each small container to saturate the potting mix, using slightly warm tap water. Never allow containers to sit in standing water. Throw away excess water that seeps into the trays.
Put the leak-proof trays in a warm location such as the top of a refrigerator or freezer to help seed germinate, usually in seven to 10 days. A sprout emerging from the potting mix indicates germination.
Plants need a bright area to grow indoors, but unfiltered sunlight will dry out the containers too quickly.
After seed germinate, move the trays to a south window or sunroom with filtered light. An alternative is to put incandescent or fluorescent bulbs six to eight inches from the containers to provide light necessary for germination. Leave the lights on all the time, and occasionally rotate plants that begin to grow towards the light source. Fluorescent lights are preferable because they do not get as hot as incandescent lights.
A hot bed or cold frame may be a good investment for gardeners planning to produce lots of seedlings to transplant each year.
It is critical for newly-germinated seedlings to have water available for the next two to three weeks, so frequently check the moisture content with your finger to keep from damaging tender roots. Carefully and consistently water when the soil feels dry a little below the surface for the first two weeks. You can slowly apply a water-soluble fertilizer the third week. Be sure to follow instructions for the amount of fertilizer to use.
To avoid common problems starting seed indoors, use a high-quality starter mix, don’t plant seed too early; select a warm area to germinate seed; provide a high-light environment for seedlings to grow; and keep developing seedlings moderately moist.
For more information on other gardening or horticultural topics, contact the Harlan County Cooperative Extension Service at 573-4464.
Jeremy Williams is the Harlan County extension agent for agriculture & natural resources. Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability or national origin.