What You Need to Know About Lettuce: A Comprehensive Guide

What is lettuce?

Lettuce is an annual plant that is in the same family as Cabbage, Broccoli, and Cauliflower. It is a leafy vegetable that is primarily eaten raw and grows easily in your spring or fall garden. There are many different types of lettuce, including the popular Butterhead, Iceberg, Romaine, and Leaf Lettuce. It is typically grown in cooler climates and can withstand temperatures below 30 degrees.

With a bit of guidance, you too, can grow this green successfully. This guide outlines what you need to know so that the lettuce in your garden thrives.

Lettuce Height

Lettuce typically grows to be anywhere between 4 to 30 inches tall. Depending on the variety, it can have a spread between 4 to 20 inches wide. It is easy to get started, although most types thrive in cooler weather. Much like kale, lettuce will bolt when it is too hot.

Considered one of the more popular vegetables, there are numerous varieties. You may have heard of Iceberg, Romaine, and Buttercrunch, but many heirloom varieties such as Oak Leaf Lettuce, “Speckled” Lettuce, and Black-Seeded Simpson are making a comeback.

Lettuce Soil

Lettuce prefers soil that is high in organic matter and drains well. The ideal pH for lettuce is 6.0 to 6.8. If your soil is too sandy, you can add compost or other organic matter to help it retain moisture better. Mulching with straw or wood chips can also help your soil retain moisture and lessen the need to water.

Lettuce Planting

You can start planting lettuce indoors about four to six weeks before the last frost date in your area. To do this, fill seed trays or pots with moistened potting mix and plant the seeds about 1/4 inch deep. Place the trays or pots in a warm, sunny spot and keep the soil moist. Once the seedlings are big enough to handle, transplant them into your garden.

If you want to plant lettuce directly in your garden, wait until the soil temperature is at least 45 degrees Fahrenheit. You can plant the seeds about 1/4 inch deep and thin them out to about 6 inches apart once they sprout. Lettuce typically takes about one to two weeks to germinate.

Lettuce Sun Requirements

Lettuce needs at least six hours of sunlight a day. It does well in partial shade and can be interplanted with larger vegetables that shade it from the sun.

Lettuce Watering

Lettuce needs to be kept moist and should be watered about one to two inches per week. More water may be necessary during hot, dry weather.

Lettuce Planting Times

Lettuce can be planted in the spring or fall. It is a cool-season crop that does not do well in the summer as it struggles when temperatures increase to over 85 degrees. In most areas, you can plant lettuce as soon as the soil can be worked in the spring. Fall planting can be done about six to eight weeks before the first frost date in your area.

Days to Maturity

The days to maturity will vary depending on the type of lettuce you are growing. Most varieties will be ready to harvest in 50 to 70 days.

Lettuce issues

Lettuce is easy to grow but does have many pests and diseases that may inhibit a good harvest. Pests include:

-Aphids

Aphids are small, pear-shaped insects that come in a variety of colors, ranging from green, brown, or pink. They’re frequently discovered in clusters on the undersides of leaves and can cause stunted growth as well as deformed leaves. If you notice the leaves on your lettuce have become stunted, look for ants. They can be a sign that you have an aphid infestation as they secrete honeydew that attracts aphids.

Solution – You may either wash the aphids off your lettuce with a powerful stream of water from the hose or use insecticidal soap. Insecticidal soap is a contact killer, which means it only works if it directly touches an insect. Insecticidal soap works best on heavier infestations.

-Cabbage loopers

A cabbage looper is a tiny caterpillar that is generally green with a yellow stripe on its back and measures approximately 1 – 1-1/2 inches long. It is called a looper because it “loops” when it moves. If your lettuce has been damaged by cabbage loopers, you may expect small, jagged wounds in the leaves.

Solution – You can pick these caterpillars off and squash them incredibly easily. You can also spray your foliage every two weeks with BT. BT, or Bacillus Thuringienis. BT is an organic pesticide that is effective against caterpillars. They ingest it and stop feeding, eventually dying.

-Cutworms

A cutworm is a type of caterpillar that is brown or black and measures approximately 1 – 1-1/2 inches long. They get their name from the fact that they “cut” young plants off at the ground level, often overnight. If you notice your lettuce has been cut off at the ground, chances are you have a cutworm infestation.

Solution – The best way to get rid of cutworms is to hand pick them off and drop them into a bucket of soapy water. You can also try setting out small cardboard collars around each seedling. The collars should be about 2 – 3 inches tall and placed an inch or two into the ground. This will prevent the cutworms from getting to your plants.

-Flea beetles

Flea beetles are tiny, black beetles that jump like fleas when disturbed. They’re most commonly found on brassicas, such as cabbage and broccoli, but can also attack lettuce. The damage they cause appears as small, round holes in the leaves.

Solution – You can try dusting your plants with diatomaceous earth to keep flea beetles away. Diatomaceous earth is a powdered fossil that works by cutting into the beetle’s exoskeleton, causing it to dehydrate and die. You can also try using an insecticide such as Pyrethrin or Neem oil.

-Grasshoppers

Grasshoppers are the bane of many people’s gardens. These voracious eaters can strip a plant of its foliage in no time flat. If your lettuce has been damaged by grasshoppers, you will notice large, ragged holes in the leaves.

Solution – The best way to get rid of grasshoppers is to hand pick them off and drop them into a bucket of soapy water. You can also try using bait such as Sevin or Orthene. Be sure to follow the manufacturer’s instructions when using any type of pesticide.

-Slugs and snails

Slugs and snails are slimy, soft-bodied creatures that love nothing more than munching on tender young plants. They leave behind a telltale slime trail and can do serious damage to your lettuce if left unchecked. Slugs and snails are most active at night, so you may not even know you have an infestation until it’s too late.

Solution – The best way to get rid of slugs and snails is to handpick them and drop them into a bucket of soapy water. You can also try setting out small dishes of beer around your garden. The slugs and snails will be attracted to the beer and, when they go to drink it, drown.

-Leafhopper

Leafhoppers are small, green or brown insects that measure approximately 1/8 inch long. They get their name from their ability to “hop” away when disturbed. Leafhoppers feed on the sap of plants and can cause damage by sucking the nutrients out of the leaves. This results in small, pale spots on the foliage.

Solution – You can try using an insecticide such as Pyrethrin or Neem oil. You can also try planting marigolds around your garden. Marigolds produce a chemical that is toxic to leafhoppers and will help to keep them away.

-Lettuce root maggots

Lettuce root maggots are the larvae of flies that are attracted to manure. They invade the roots of lettuce plants and feed on them, causing the plants to wilt and die. If you suspect your lettuce has been damaged by root maggots, you will notice small, white grubs in the roots.

Solution – The best way to get rid of root maggots is to keep your garden clean and free of debris. This will help to discourage the flies from laying their eggs. You can also try using an insecticide such as Pyrethrin or Neem oil.

Common diseases include:

-Downy mildew

Downy mildew is a type of fungal disease that can affect many different types of plants, including lettuce. This disease is characterized by small, yellow spots on the leaves. The spots eventually turn brown and the leaves will die and fall off. Downy mildew is most commonly found in damp, humid conditions.

Solution – The best way to prevent downy mildew is to water your plants early in the day so that the leaves have time to dry off before nightfall. You can also cut off infected leaves, spray your plant with baking soda, or spray with a diluted mixture of hydrogen peroxide.

-Damping-Off

Damping-off is a type of fungal disease that affects seedlings. The fungus attacks the stem of the plant, causing it to rot. This can cause the plant to collapse and die. Damping-off is most commonly found in wet, humid conditions.

Solution – The best way to prevent damping-off is to water your plants early in the day so that the soil has time to dry out before nightfall. You can also try by planting in only well-draining soil and avoid overcrowding your plants.

-Mosaic disease

Mosaic disease is caused by a virus that affects many different types of plants, including lettuce. The symptoms of this disease include yellow or brown patches on the leaves. The leaves may also curl up or become distorted. Mosaic disease can spread quickly and can kill an entire crop if left unchecked.

Solution – There is typically no rehabilitating a plant infested with Mosaic. The best way to prevent it is to buy virus-free seedlings from a reputable nursery. If your lettuce plants are infected, trash the plant and DO NOT COMPOST! You may need to burn infected lettuce and remove any soil that may have become contaminated.

-Bottom Rot

Bottom rot is a type of fungal disease that affects the roots and lower stem of plants. The symptoms of this disease include yellow or rust-colored spots on the leaves, wilting and can cause plant death. Bottom rot is most commonly found in wet, humid conditions.

Solution – The best way to prevent bottom rot is to water your plants early in the day so that the soil has time to dry out before nightfall. Rotating your beds can help prevent Bottom rot as well as promote air movement and drainage.

Lettuce Harvesting and Storage

You can start harvesting lettuce when the leaves are large enough to eat. For most varieties, this will be when the plant is about 6 inches tall. You can either cut the entire plant or just remove the outer leaves, leaving the plant to continue growing. Lettuce will bolt (flower and go to seed) when it gets too hot, so it’s best to harvest before that happens.

Lettuce can be stored in the refrigerator for about one to two weeks. To store, wrap the leaves in a damp paper towel and place them in a plastic bag. You can also store lettuce in a perforated plastic bag or container filled with an inch of water.

Why you should grow lettuce

Lettuce is a cool weather crop and can be one of the first things you plant in the spring. It can also be planted in your fall garden to provide your family with additional food and extend your growing season.

It is fast growing, can be ready to harvest in as little as 30 days, and can be used in salads, sandwiches, wraps, and more. Not only is it relatively easy to grow, but it doesn’t require a lot of space. Lettuce can be grown in containers, raised beds, or in the ground. It is a good source of vitamins A and K, as well as folate and fiber. Growing your own lettuce also allows you to have more control over the quality of the food you are eating.

If you are looking for a tasty crop to grow in your fall garden, try some lettuce! With numerous varieties to pick from, low-maintenance care, and it’s reduced water needs, it is an easy harvest that everyone in your family will enjoy.