Lettuce is cool-season crop that grows well in the spring and fall in most regions. This crop is perfect for beginners; it’s easily sown by seed directly in the soil as soon as the ground can be worked. Because lettuce grows quickly, the best approach is to plant a small amount of seeds at a time, staggering the plantings.
Lettuces are a great leafy green because they grow quickly, produce for a long time, and are not very demanding as long as you keep the plants sufficiently watered. Plus, lettuce grows great in raised beds making it ideal for small spaces. Lettuces are perfect for containers, which can be placed on decks, patios, balconies, and porches.
Lettuce prefers a location with 5 to 6 hours of sun, but can benefit from afternoon shade when temperatures soar. Soil should be loose, well-draining, and moist but not soggy. In weeks prior to planting, amend with plenty of compost for added fertility.
When to Plant Lettuce
- Soil temperatures between 45°F and 65°F are ideal. Cold-adapted varieties can survive much lower temperatures.
- Direct sowing is recommended. Plant seeds in the ground 2 to 4 weeks before your last spring frost date or as soon as the ground can be worked.
- Or, to get a head start, start seeds indoors about 1 month before your last spring frost date. Harden off seedlings for 3 days to a week before setting outdoors.
- If you are buying transplants (small plants) from a garden center or nursery, you may plant between 2 weeks before your last spring frost to 2 weeks after your last spring frost.
- In most regions, it’s possible to plant another crop of lettuce in the fall or even early winter. See our Planting Calendar for planting dates.
- Tip: To plant a fall crop, create cool soil in late August by moistening the ground and covering it with a bale of straw. A week later, the soil under the bale will be about 10°F (6°C) cooler than the rest of the garden. Sow a three-foot row of lettuce seeds every couple of weeks—just rotate the straw bale around the garden.
How to Plant Lettuce
- Since the seed is so small, a well-tilled seedbed is essential. Stones and large clods of dirt will inhibit germination.
- Plant seeds 1/8 to 1/4 of an inch deep. Lettuce seeds need light to germinate, so don’t sow them too deep.
- Seed may be sown in single rows or broadcast for wide row planting (loose-leaf varieties are best for this). When broadcasting, thin 1- to 2-inch tall seedlings for the proper spacing.
- Spacing between plants depends on the variety:
- Loose-leaf lettuce: Plant or thin to 4 inches apart.
- Romaine (cos) and butterhead (loose-head, Bibb, Boston) lettuce: Plant or thin to 8 inches apart.
- Crisphead (iceberg) lettuce: Plant or thin to 16 inches apart.
- Set rows of lettuce 12 to 15 inches apart
- Sow additional seeds every 2 weeks for a continuous harvest.
- Consider planting rows of chives or garlic between your lettuce to control aphids. They act as “barrier plants” for the lettuce.
- Water thoroughly with a mist nozzle at time of transplanting or seeding.
For a fall crop, cool the soil in August by moistening it and covering it with a bale of straw. One week later, the soil under the bale should be a few degrees cooler than the rest of the garden and ready to be sown with a 2-foot row of lettuce. Repeat the process every couple of weeks by rotating the straw bale around the garden. As autumn temperatures decline, seed as usual for a fall harvest.
You can help transplants along at the start of the season by covering them with a temporary cloche made from bottomless milk cartons or plastic bottles – demo of this. These will keep the chill off your seedlings just enough to help them acclimatize. Newly planted lettuces may also be helped with a simple row cover or fleece.
- Fertilize 3 weeks after transplanting with organic alfalfa meal or another slow-release fertilizer to provide a steady stream of nitrogen.
- Make sure the soil remains moist but not overly wet. It should drain well. Over watering leads to disease or soft growth.
- Lettuce will tell you when it needs water. Just look at it. If the leaves are wilting, sprinkle them anytime, even in the heat of the day, to cool them off and slow down the transpiration rate. Using row covers can also help to keep lettuce from drying out in the sun.
- An organic mulch will help conserve moisture, suppress weeds, and keep soil temperatures cool throughout the warmer months.
- Weed by hand if necessary, but be careful of damaging your lettuce plants’ shallow roots.
- Bolting is a common problem that’s caused by warm temperatures (over 70°F / 20°C) or changes in day length. When a lettuce plant bolts, it starts to produce a central stem and seed stalk, and leaves take on a bitter flavor.
- To delay bolting, cover plants with a shade cloth so that they get filtered light. Be sure to maintain watering throughout the warmest parts of the growing season, too.
- Planning your garden so that lettuce will be in the shade of taller plants, such as tomatoes or sweet corn, may reduce bolting in the heat of the summer.
Harvest lettuce in the morning when full-size but young and tender. Check your garden everyday for ready-to-harvest leaves; mature lettuce gets bitter and woody and will go bad quickly.
- Before maturity, you can harvest leaf lettuce by simply removing outer leaves so that the center leaves can continue to grow.
- Harvest butterhead, romaine, and loose-leaf types by removing the outer leaves, digging up the whole plant, or cutting the plant about an inch above the soil surface. A second harvest is often possible when using the first or third methods.
- Crisphead lettuce is picked when the center is firm.
How to Store Lettuce
- Store lettuce in a loose plastic bag in the refrigerator for up to 10 days.
- When ready to use, put the harvested lettuce in cold water for a few minutes. Then place in a salad spinner or towel. Spin the spinner to remove water from the lettuce.
- Lettuce leaves have wilted? Put the leaves in a bowl of cold water with ice cubes and soak for about 15 minutes.