How to Grow Lettuce from Seed

When I’m at the nursery or garden center, I see small lettuce plants for sale, often for about a dollar apiece. Most of the time, there’s really no reason to buy these. It’s just as easy, and much less expensive, to frow your own lettuce from seed packets.

Packets of lettuce seeds are readily available at grocery stores and hardware stores in late winter and early spring. You can also purchase lettuce seed packets online, although these lettuce seeds are often more expensive. You can buy single varieties (one of my favorite types of lettuce is Red Sails) or seed packets of mixed lettuces. If you like spicy salads, it’s fun to try a mesclun mix, which is harvested when the leaves are small.

According to the University of Illinois Cooperative Extension, lettuce is a hardy, cool-weather vegetable that thrives when the average daily temperature is between 60 and 70°F. For this reason, it’s best not to wait until after the last frost to plant your lettuce seeds. It’s far better to plant lettuce in early spring. If you want a second crop for fall, plant more letuce seeds in late summer. You can extend your harvest by planting several short sections of row two weeks apart, instead of planting a single long row all at once.

If you have a cold frame, you can sow lettuce seeds outdoors in the cold frame six weeks before your last frost date. If you don’t have a cold frame, wait a few more weeks.

To sow lettuce seeds, use a trowel to dig a shallow trench or row directly in loose garden soil. Distribute the lettuce seeds, which are usually tiny, in a narrow band along this row. Cover your seeds with a very thin layer of soil or mulch, and water well. In good weather, lettuce seeds will sprout after as little as 1 week, but germination may sometimes take 2 or 3 weeks.

During the summer heat, lettuce grows poorly, develops a bitter taste, and forms flowers and seeds. This is referred to as “bolting.” It is possible to extend your lettuce crop further into the summer by purchasing varieties billed as “bolt resistant.”

The U of I lists 5 separate types of lettuce: leaf lettuce (also called loose-leaf lettuce), cos or romaine lettuce, crisphead lettuce, butterhead lettuce, and stem lettuce (also called asparagus lettuce).

Leaf lettuce produces crisp leaves loosely arranged on the stalk. This is the most popular type grown by gardeners, and it is my favorite. I always include leaf lettuce in my garden. The romaine type lettuce forms upright, elonagated heads much like those found in the grocery store. Butterhead types of lettuce form loose heads with tender, soft leaves and a delicate flavor. The important part of stem lettuce is a seed stalk used in stewed, creamed, and Asian dishes.

Crisphead lettuces form tight heads like the iceberg lettuce found in supermarkets. They are among the most dificult to grow. In areas without a long cool season, this is the one variety that’s better to grow from transplants. Because it’s difficult to get high-quality heads in the home garden, I generally do not bother to grow this type of lettuce.

The best time to harvest lettuce is in the morning, when plants have absorbed the most water. If you pick wilted lettuce on a hot day, it will probably not revive when you refrigerate it. If you are thinning plants to grow large heads, pull and eat the leaves of the young plants you are removing. You can also use scissors to harvest handfuls of young lettuce.

Rinse harvested lettuce thorougly to remove all grit and dry it before serving. If you are growing and harvesting many greens, you may want to invest in a salad spinner.