Getting ready for your next vegetable garden is a great way to beat the winter blues. But when should you plant those seeds you've been saving all winter? Starting vegetables in pots can result in an earlier harvest. But if they are started too early, seedlings can become root bound and stunted before they can be planted outdoors. By considering your growing season, you can get your garden off to a good start.
Your Growing Season
When to start a particular type of vegetable seed depends largely on the length of your growing season. The U.S. Department of Agriculture (USDA) has divided the United States into numbered climate zones based on average recorded temperatures. Using the USDA system, you can easily find out the first official day of your growing season, which is the average first day of the year without frost in your zone. Plan to set out tender plants on, or just after this date, depending on the weather.
Count back from the first day of your growing season to determine when to plant your seeds. Sow lettuce, broccoli, cabbage and cauliflower seeds 10 weeks before planting out. Start warmth-loving plants like eggplant, tomatoes, cucumbers and peppers seven weeks in advance. Plant fast-growing vines like cucumber, melons and squash just four weeks before you plant them out. A good indicator that your plants are mature enough to be put into the garden is the appearance of a second set of true leaves. If temperatures are still near freezing by your plan-out date, and your starts begin to outgrow their pots, you can replant them in slightly larger pots and keep them inside until the weather warms.
Some plants do not transplant well, and fare better if planted directly in the ground. These include parsley, chives, cilantro and some types of leaf lettuce. Melons, squash and pumpkins grow quickly and can become root bound if they are not grown in a large enough pot. In areas with longer growing seasons it is best to start squash and melons directly in the ground.
In areas with short growing seasons, starting late maturing crops like tomatoes and peppers early can mean a significantly larger harvest. Starting seeds indoors usually results in more plants because of higher germination rates and less loss because of predators. Healthy transplanted seedlings will usually mature faster than those planted directly in the garden.
Do not transplant seedlings into the garden without first hardening them off for at least two weeks. If they are planted out directly, their tender leaves might be burned by direct sun, or harmed by cold winds. Gradually expose them to more sunlight and cooler temperatures by placing them in a sheltered location in semi-shade. If night temperatures are near freezing, take them back inside or put them in an outdoor cold frame. Slowly move them into a sunnier area, with conditions similar to your garden.