When to Plant Lettuce Seed Outside in South Carolina

Spring Planting Dates

• Direct sow lettuce seeds outdoors in prepared soil two weeks before the last expected frost date in your zone. Lettuce is tolerant of a light frost, so if temperatures drop or an unexpected cold snap hits, it should be fine. If the seeds have sprouted, but a hard freeze or heavy frost is expected, cover the crops with burlap or an old bed sheet. Start seeds six weeks before your last expected frost date in protected areas like low rows or cold frames. Continue to sow seeds every two weeks until soil temperatures reach the maximum ideal sowing temperature of 75 degrees Fahrenheit.

Fall Planting Dates

• Start fall lettuce eight weeks before the first expected fall frost date in your hardiness zone. Sow every two weeks through the fall for continuous harvest through the beginning of winter. In USDA zones 8 and 9 where temperatures rarely drop below 20 degrees, hardier varieties of lettuce such as buttercruch may be able to overwinter outdoors unprotected. In northern areas, where temperatures are likely to drop below 20 degrees, lettuce can still be grown under low rows or in cold frames throughout winter.

How to Plant

• Leaf lettuces should be broadcast seeded -- sprinkle on top of the soil -- at a rate of about one seed per inch. When seedlings start to grow and get crowded, thin them as needed to provide plenty of room for the remaining plants with final spacing in accordance with the type of lettuce you're growing. Leaf lettuce is usually thinned to 6 inches apart, while some head lettuces will require a 12-inch spacing. Seeds usually germinate in less than a week. Water lightly after sowing and keep the soil moist until the seedlings are a few inches tall.

Maintenance

• Work compost into the soil before planting at a rate of about 1 gallon per 100 square feet. This light feeding should be enough to keep lettuce healthy throughout winter. When seedlings are at least 4 inches tall, mulch heavily with straw to keep the soil from getting too cold and to keep the area moist.