Lettuces are cool weather crops usually planted in early spring. Many varieties are also successful in autumn and early winter gardens and, with a bit of protection, provide fresh greens for your table nearly all year long,
When to Plant Fall Lettuce
To grow fully mature lettuces for late autumn and winter harvests, sow seeds directly into the garden ten to 12 weeks before the first frost. Crops can be harvested early as baby lettuce but need protection to reach mature growth when temperatures drop below 32°F.
If you want to grow only baby lettuces, sow seeds four to five weeks before final frost.
Lettuce seed can also be started indoors for transplant into the garden or sown directly into a cold frame, high tunnel, or greenhouse. If choosing one of these methods, plant seeds six to seven weeks before the first frost.
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How to Grow Lettuce in the Fall
Many types of lettuces mature quickly, making them ready to harvest in as few as 30 days. Others may require up to 100 days. For successful autumn and early winter harvests keep in mind the following key factors.
- Seeds will not germinate at temperatures below 32°F. and are forced into dormancy above 70°F. This makes late summer and early autumn planting tricky in climates with hot, dry, late-season weather.
- Keep the seedbed moist until germination occurs. A light shade cover can aid germination by reducing heat. In the end, you may have better success starting seedlings indoors and transplanting them into the garden.
- Although lettuce grows best at 60°F to 65 °F, day length determines growth rate. During short winter days, development slows until daylight hours lengthen. As long as plants are protected from freezing temperatures, they’ll resume growing.
- Methods are not much different than planting in early spring. Baby lettuces are directly sown and not grown for transplant. Sow seeds about 1 inch apart and 1/4 inch deep, cover lightly with soil and keep moist.
For mature lettuces, decide which method to use, either starting seed indoors for transplanting out or sowing seed directly into the garden, or into a season extender like a cold frame.
How to Direct Sow Late Lettuce
These steps are the same for outdoor beds, high tunnels, and cold frames.
- Choose a spot that receives five to six hours of sunlight daily.
- Prepare a garden bed 6 to 8 inches deep, working in well-aged compost.
- Scatter seeds or plant them 1/4 inch deep and 6 to 8 inches apart in rows 12 inches apart. Cover lightly with soil. Space seed for crisphead varieties 12 inches apart.
- Water and keep soil moist until germination occurs, usually in seven to 14 days.
- Once several sets of leaves appear, you have the option to add fertilizer. Use an organic product such as bloodmeal or kelp or side dress with a granular NPK 5-10-10 and water in.
- Continue watering when the top inch of soil gets dry.
- Protect exposed plants from freezing air temperatures by installing a season extender such as a freeze cloth or a hoop tunnel.
Grow Lettuce Transplants For Autumn and Winter Harvest
- Fill a seed starting tray with a slightly dampened, loose, well-draining mix with little to no fertilizer. A potting mix formulated for vegetables is a good choice.
- Sow one or two seeds per cell or 6 to 8 inches apart in a flat. Plant seeds 1/4 inch deep and cover lightly with potting mix. You can also scatter sow seeds and thin plants once they sprout.
- Water and keep soil consistently moist but not soggy until germination in seven to 14 days.
- When seedlings are 2 to 3 inches tall with several sets of true leaves, transplant them into the garden bed.
- Fertilize with bloodmeal, fish emulsion, or side dress with a granular NPK 5-10-10 and water in.
- When temperatures dip below freezing protect plants with freeze cloth or similar cover.
Best Types of Lettuce For Fall Growing
There are essentially four main types of lettuce with various cultivars suited for autumn and winter crops.
Romaine Lettuce
Romaine lettuces feature tall, elongated leaves with sturdy center ribs. Outer leaves are dark green with lighter inner leaves that have crisp texture and earthy to slightly bitter flavor. Romaine is ready to harvest in about 65 days.
Butterhead Lettuce
Butterhead lettuces feature large, buttery soft leaves formed in loose heads. They have a tender texture and mild, sweet flavor. Butterhead lettuces mature in 50 to 60 days.
Looseleaf Lettuces
Looseleaf lettuces are sometimes described as ‘cut and come again.’ Leaves grow from a central stem and may be green or red with ruffled tops and crisp stems. The texture is crunchy with a mild, sweet flavor. Leaves are harvested individually as they mature starting in four to six weeks.
Crisphead Lettuces
Crisphead lettuces form tight, rounded heads of light green, overlapping leaves. The texture is crunchy with a neutral, mild, slightly sweet flavor. This type requires the longest growing time of up to 100 days to reach harvest maturity. Crisphead varieties are developed for greater heat rather than cold tolerance and most varieties can be grown as winter crops with protection.
How to Protect Lettuce in Early Winter
Lettuces with sturdier, compact leaves like romaine and crisphead are better suited to withstand frost which improves the flavor of some varieties. All lettuce leaves, though, turn soggy and lose shape when exposed to freezing temperatures.
Season extenders like cold frames, greenhouses, and high tunnels are ideal places to grow winter lettuce crops. For lettuces grown in the garden, keep thermal or freeze blankets handy along with a set of hoops or other supports.
Avoid placing covers directly on top of plants which can trap moisture and damage leaves. In areas with extended freezes, leave covers in place or remove them during daytime hours when air temperatures rise above 32°F.