Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

When can I plant warm season vegetables?

While the majority of vegetables grown in home gardens are started from seed planted directly into the soil outdoors, you can plant some of these seeds indoors to get a head start on the season. Plants produced indoors and later set into the garden are called transplants. The advantage of setting out transplants is that these plants are less sensitive to cool weather, become established and grow to full size quicker, and set fruit in a shorter time. If you are growing a small vegetable garden, it is perhaps easier to buy transplant seedlings. However, growing plants indoors from seed is easy, can be quite fun, and allows you to grow varieties not available as transplants.

March 15 is the time to sow select warm-season vegetable seeds indoors. These include tomatoes, peppers, and eggplant. These vegetables require warmer temperatures and are sensitive to cool conditions below 65 degrees. Generally, warm-season vegetables are set out into the garden after May 10. This date represents the historic latest spring frost for St. Louis. However, in five out of ten years, the last frost occurs as early as April 15. If you are a gambler, you can try transplanting warm-season vegetables between April 15 and May 10 and be safe half of the time without additional protection.

Sowing seeds to produce transplant seedlings is quite easy. If you have seeds left over from last season, try running a seed germination test. Put three paper towels on a plate and line out 25 seeds, then cover with another paper towel; moisten, and put into a plastic bag. In a week to 10 days, count the number of germinated seeds. Multiply by four to get the percent germination. If it is less than 75 percent, buy new seeds.

When you buy seeds, make sure they are of varieties best suited for the local climate. Some of the best for this area are labeled F1 hybrids and "All America Selections." Consult MU Guide #6201, Vegetable Planting Calendar, for a list of recommended varieties. The F1 hybrids are products of crossing true-breeding parent lines. They are typically stronger, earlier to bloom, and more productive than non-hybrid types. The "All America Selections" represent varieties of superior quality as evaluated around the U.S. These are judged against the best varieties currently on the market. These selections are not always available off the rack. Seed catalogs are typically the best source, but place orders early to get what you want.

The easiest way to plant seeds is to buy a general seed- starting soil which is disease-free and normally contains enough nutrients to support young plants. Choose a container with good drainage; commercial seeding trays, clay or plastic pots, and milk cartons work well. Sow the seeds thinly at the proper depth, labeling each variety. Water thoroughly, without washing the soil, and retain moisture by covering with plastic, newsprint or glass until the plants emerge. The room temperature should be around 70 degrees. Lower temperatures will delay germination and promote rotting.

Once germinated, move the plants to a lighted area or underneath a fluorescent light 12 inches away from the light bulb. Leave the light on for 12 to 18 hours or more and fertilize weekly. Plants can be kept this way until they are transplanted into the garden after they have developed their first set of true leaves. If further growth occurs, transplant them into larger containers so as not to retard root formation.