Try jump-starting your plants indoors from seed. It's easier and faster to transplant seedlings exactly where you want them than to thin out the leafy crowd in the ground. And because you'll be planting seedlings instead of seeds outside, you'll also have a head start on the growing season-a plus in areas with short summers. Here's a tip to keep lettuce (Lactuca) all summer long: In spring, choose lettuces with different maturity dates. Heat-tolerant, slow-bolting types (those that don't produce seed as quickly) can be transplanted into your garden last. If you're planting lettuce where your summer garden will grow, plant it between the rows where you'll be sowing hot-weather lovers such as tomatoes and peppers.