How To Grow And Care For Lettuce

Adaptable in a vegetable garden, containers, or flower border, lettuce presents garden-fresh flavors, jewel-like colors, and unique freshness that revivals produce market varieties. Ideal for beginner gardeners, lettuce (Lactuca sativa) is an easy-to-grow annual vegetable that matures quickly. Growing lettuce in your backyard provides a wealth of fresh, leafy produce throughout the growing season.

Plant Attributes

Plant Attributes
Common Name:	Lettuce, Garden Lettuce
Botanical Name:	Lactuca sativa
Family:	Asteraceae
Plant Type:	Annual, Vegetable
Mature Size:	6 in. tall, 2-12 in. wide
Sun Exposure:	Full, Partial
Soil Type:	Loamy, Sandy, Moist, Well-drained, Rich
Soil pH:	Acidic to Neutral (6.0 to 7.0)
Bloom Time:	Spring, Summer
Flower Color:	Yellow
Hardiness Zones:	Zones 3-10 (USDA)
Native Area:	Mediterranean

Lettuce Care

From early spring straight into summertime, lettuce grows fast and flavorful. Choose a location that receives direct sunlight for at least four to six hours. Lettuce requires rich, well-drained soil. Amend clay soils with compost or finely ground bark.

Try growing containers on a sunny porch or deck for fresh lettuce right at your doorstep. Sow seeds directly into large pots, along with early spring greens such as arugula, cilantro, and nasturtium. They'll add more flavor to a salad. You can also start transplants indoors in midwinter by sowing five to seven seeds per pot. As the seedlings grow, transplant them to larger containers. However, keep the pots small enough to be moved easily. That way, you can bring them inside during severe weather.

With warmer days and nights of late spring, lettuce begins to bolt. It grows tall and becomes bitter. Then it blooms and sets seed. Now is the time to pull it out and plant summer vegetables and flowers. But remember, you can have fresh lettuce again in the fall.

Light

Lettuce grows best in areas with full sun exposure, typically at least four to six hours daily, but in areas with the harsh afternoon heat, lettuce benefits from partial shade. Cold-adapted lettuce varieties can survive in places with lower soil temperatures, but most prefer moderate temperatures to prevent produce from growing leggy or weak.

Soil

Lettuce grows best in loamy, loose soil that's well-draining and rich in organic matter. Aim for a soil pH that's slightly acidic to neutral, similar to other vegetable growing conditions. Soil temperatures between 45°F and 65°F are best. Amend soil with compost or manure to achieve healthy plants.

Water

Prevent disease or weak growth by keeping the soil moist but not overwatered. Soil that's too dry causes lettuce to bolt or scorch. Use your hands to feel the top inches of soil to maintain an evenly moist environment. A continuous moisture supply will yield the best results. 

Temperature and Humidity

While some varieties are cold-tolerant, lettuce will not tolerate freezing temperatures. Avoid summer bolts or bitter leaves by stopping growth at least a month before the intense summer heat. The ideal growing temperature is around 60°F to 65°F. Temperatures that exceed 65°F will start impacting development, but at long as lettuce gets a break during the evening with cooler nights, it should be somewhat tolerant. Keep humidity in check by providing adequate airflow and moist soil. 

Fertilizer

Lettuce thrives in soil amended with organic compost or manure. Amended soil helps preserve moisture, moderates temperatures, and prevents weeds from growing. Add fertilizer high in nitrogen before planting, including alfalfa or blood meal products. During the growing season, add a balanced, water-soluble fertilizer like a 5-5-5 or a 10-10-10 every two weeks to promote healthy leaves.

Types of Lettuce

Various textures and flavors categorize lettuce types, including crisphead, butterhead, loose-leaf, romaine, or cos. Here are a few cold-tolerant and heat-tolerant lettuce varieties to know:

• Lactuca sativa 'Arctic King': Sow in the fall for a spring harvest of slightly crinkled and crunchy green leaves. 
• Lactuca sativa 'Buttercrunch': This small lettuce variety, known for its "buttery" and velvety flavors and texture, prefers moderate climates. 
• Lactuca sativa 'Two Star': Vibrant and bolt-resistant, lettuce has ruffled, tender leaves this summer.

Pruning

Lettuce does not require additional pruning, as harvesting the leaves will help trim the plants throughout the growing season. Keep up with maintenance by removing dead or broken foliage. Provide adequate airflow to prevent diseases or pests from spreading. 

Propagating Lettuce

Lettuce easily propagates from scraps. While it won't yield massive results, this method is a quick and interesting method for propagating lettuce in water: 

1. Cut the leaves using a lettuce head using a sharp, clean knife about half an inch from the bottom. 
2. Place the leaves (about half to one inch tall) in a shallow bowl of clean water. 
3. Position the bowl near a sunny window, requiring at least four to six hours of daily sunlight. 
4. Change the water every two to three days by carefully draining and replacing it in the shallow bowl. Be mindful not to disturb the roots once they emerge. 
5. In about seven to 10 days, lettuce scraps will fully form. Lettuce does not grow beyond this point and will likely decline in health if left in the water.

How to Grow Lettuce From Seed 

The most economical way to grow the best lettuce selections is from seeds. Purchased transplants are faster, but your choices may be fewer. Lettuce seeds germinate best in cool soil. If you want to be sure to get the earliest harvest possible, start two to four weeks before the last expected frost. That's February in the Middle South and March in the Upper South. Lower and Coastal South gardeners can grow lettuce all winter, beginning with the first planting in October. Seeds are inexpensive, so sow them in different beds every two to three weeks. You will have an early crop in the years you don't get a hard freeze. 

Lettuce seeds require light to germinate. Sprinkle seeds on top of the soil, and lightly cover or scratch them into the bed just below the soil's surface. Lettuce must be kept moist throughout its growing season. As seedlings mature, thin them when they are two or three inches tall by gently pulling out the largest plants. These will make your first salad, even though they are small. Leave six to eight inches between the remaining plants for sufficient room to mature. If pulling the seedlings is difficult, pinch them off instead. Remember to start with the more cold-tolerant lettuce selections in the cool months and then sow the heat-tolerant ones later to help carry you through the warming days of spring.

Expect to harvest lettuce 45 days after planting and semi-heading selections in about 50 days. Pick the outer leaves first, as the plant will continue growing and producing, or cut the entire plant two inches above the base. The new plants may not have the lovely form of the original, but this will help produce more leaves. To store lettuce, soak it immediately in an ice water bath for five minutes. Then drain, and keep in zip-top plastic bags in the refrigerator.

Overwintering

As an annual plant, it is optional to overwinter lettuce. Lettuce will not survive in freezing temperatures, so harvest the produce in the fall before the first frost. Gradually introduce cold-tolerant varieties to lower temperatures to extend the growing season. Additionally, planting lettuce in containers is another way to extend the growing season, as you can move the plant indoors during extreme cold. If growing outdoors, cover the ground in organic matter such as wood chips, straw, or pine needles to help retain moisture and protect from frostbite. 

Common Pests & Plant Diseases 

Lettuce is an easy-to-grow vegetable but is still susceptible to pests. Aphids, cutworms, earwigs, slugs, and whiteflies are sometimes found on lettuce varieties but treated with soapy water or insecticidal soap.

If grown in the right environment and with proper care, lettuce does not generally have many diseases, but powdery mildew, lettuce mosaic virus, and white mold can still impact the plant's growth. Additionally, bolting from too much sun exposure can prevent the vegetable from developing and cause its leaves to turn bitter. Delay bolting by blocking the harsh sun with a cloth to help filter the sunlight and maintain adequate watering. 

Common Problems With Lettuce

While relatively pest-resistance and disease-free, lettuce still has some problems that might arise. Here is what to know to help maintain healthy lettuce plants:

Leaves Turning Yellow

Mosaic virus presents differently in fruits, vegetables, and flowers, but the virus distorts foliage with its blister-like appearance. Foliage might turn yellow or white and have darker spots. Additionally, the foliage may begin to curl or wilt due to the spreading virus. Prevention is critical for the mosaic virus as there is no treatment. Infected plants need to be removed and discarded. After, disinfect garden tools to avoid spreading the virus to other plants. 

Leaves Turning Black/Brown 

Lettuce plants growing in soggy soils are prone to downy mildew. This fungus-like disease causes foliage to have brown spots and wilting leaves. Typically visible on the underside of leaves, downy mildew appears similar to powdery mildew, but fungicide will not treat it. If downy mildew is present, remove infected foliage immediately to prevent it from spreading. Provide plants with proper circulation and the soil moist but not soggy.