By: Sandy Feather ©2008
Penn State Extension
Q. Last year I started my own vegetable plants for the first time. I may have planted some seeds too early because some seedlings turned into out of control cucumber and tomato plants. When is the best time to start vegetable seeds indoors?
A. Most people make the common mistake of planting vegetable seeds indoors too early. The resulting transplants get too big and woody by the time gardeners are ready to set them out in the garden, and the plants do not adapt as well as less mature transplants. As a rule of thumb, start your cool-season crops from mid- February to early March. These are crops that grow best in cool weather, but bolt to seed and/or get bitter during hot weather.
Start cole crops such as broccoli, cabbage, cauliflower, Chinese cabbage and kohlrabi eight to nine weeks before you want to plant them out in the garden. Start iceberg and romaine lettuce about four weeks before transplanting them into the garden.
Other types of lettuce such as leaf or butterhead are best seeded directly into the garden. Cool-season crops can be planted outside early to mid-April, as the weather warms and the soil dries out enough to work.
Warm-season crops -- those that are not planted out in the garden until all danger of frost has passed in late May -- should not be started indoors until late March or early April.
Give tomatoes, peppers and eggplants eight to nine weeks before you want to plant them in the garden. If you start your cucumbers, melons and gourds indoors (they, too, can be direct-seeded in the garden), start them four weeks before planting them in the garden. This should keep them from getting too big and taking up too much space inside.