How to Grow Salad Greens
Plant seeds in the earliest days of spring, and you’ll have the makings for fresh salads in summer.
Lettuce is a cool-weather crop, and seeds can go in the ground about four weeks before the last frost. (If you live in a warm region, you can grow lettuce until the highest daytime temperature remains steadily above 80 degrees.) Check with your local county agent or State Cooperative Extension Office (the numbers are in the "Government" section of the phone book) for planting requirements; their websites often have answers, as well as links to the volunteer-staffed Master Gardener program. The U.S. Department of Agriculture's site, gardening.gov, is also full of regional climate and soil information. Plan for your last harvest before it gets too hot. Most lettuce varieties go from seed to salad in 45 to 80 days. And if you sow seed every 8 to 10 days, you should have a constant supply all spring, even in a small space.
Till the soil well before planting. Because lettuce is one of the first things to go into the ground, the earth will probably be solid and inhospitable to small seeds. You can also use almost any container to grow lettuce. Just make sure it's at least six to eight inches deep and has good drainage.
Lettuce seeds are the size of pinpoints, so burying them too deep can make it hard for them to germinate. Check seed-packet labels for instructions. Scatter the seeds directly onto the ground; you will thin the plants as they grow.
Depending on your climate and weather, water a few times a week or every day. Don't let the soil get too dry or the plants will wilt. And don't hose down lettuce until puddles form.
You won't need a lot of fertilizer (lettuce isn't as demanding of nutrients as flowering plants), but make sure that any fertilizer you use is suitable for edibles. Look for the words "organic mix" on the label, or check with your nursery. Garden compost is a safe alternative.
When leaf-lettuce plants are about one inch high, you can begin thinning and eating the lettuce. Use scissors to cut or snap off the shoots. This will prevent the roots of the remaining plants from being disturbed and give the plants room to thrive. To thin head lettuce, simply uproot the immature head. Keep thinning until plants are 4 to 10 inches apart, depending on the variety; head lettuce needs more space so it can form a ball.
When your lettuce is fully grown (check the information on the seed packet), pick it immediately and enjoy. During the growing season, you can sow new seed almost weekly so there will always be more on the way. When the leaves grow longer than four to six inches, you may find them too tough and bitter. So discard overgrown plants, which will make room for new seedlings.