By Erin Marissa Russell
Lettuce is one of humanity’s oldest foods and a popular addition to the vegetable garden for beginners and expert gardeners alike. This standard of the veggie patch is so popular because it’s a low maintenance crop that usually doesn’t struggle with diseases or infestation by garden pests. Lettuce also has the benefit of being a natural space saver, producing a sizable harvest in exchange for quite a small investment of garden square footage. With so many different varieties of lettuce available, there’s one to suit every taste and every climate.
Keep reading to learn everything you need to know to choose lettuce varieties for your garden, plant them, and nourish them to maturity. Our section on companion planting will guide you in selecting plants to grow alongside your lettuce and warn you against plant partnerships that will drag one another down instead of building one another up. We’ll also discuss troubleshooting in case your lettuce plants do happen to face a plant disease or insect problem as well as how to harvest and store your crop. First things first—here’s a rundown of the essentials of lettuce cultivation.
The Basics on Growing Lettuce
Botanical Name: Lactuca sativa L.
Common Name(s): Lettuce, garden lettuce
Plant Type: Annual or biennial leafy herbaceous plant eaten as a vegetable
Mature Plant Size: 12 to 40 inches tall; 6 to 24 inches wide (size depends on lettuce variety)
Days to Maturity: Average of 45-55 days from seed for most varieties, except heading types, which need a little longer. Romaine generally matures in 75-85 days, and most crisphead lettuces mature in 70-100 days. Starting with baby plants instead of seed reduces the maturation period by 10-14 days. Cool weather can push harvest date back by up to 21 days; hot weather can make harvest up to 7 days earlier.
USDA Hardiness Zones: 2 through 11
Temperature Tolerance: 60-65 degrees Fahrenheit (15.5-18.3 degrees Celsius) is ideal. Hardened off transplants can survive temperatures as low as 20 degrees Fahrenheit (6.67 degrees celsius), and all lettuce should withstand frost as long as the frost is not severe. Properly hardened young plants are actually hardier to cold weather than more mature lettuces. Soil temperatures of 80 degrees Fahrenheit (26.6 degrees Celsius) or warmer will trigger thermal dormancy and stall germination.
Sun Requirements: Full sun to part shade
Soil Requirements: Fertile, loose loamy soil rich with compost that drains well and has moderate water retention and a slightly acidic to neutral pH level of 6.0 to 6.8
Soil Preparation: Add compost to soil before planting; aerate soil that is not loose
When to Plant: Start lettuce from seed indoors 6-8 weeks before last expected frost in spring or direct sow 2 weeks before last expected frost in spring. Succession planting can continue every one to three weeks from spring’s last frost until the middle of June. For a fall harvest, plant eight weeks before the first expected frost of autumn.
Plant Spacing: Initial spacing = 1 inch, in rows spaced 12-18 inches apart
Planting Depth for Seeds: One eighth of an inch
Germination Temperature: Ideal germination range = 60 to 68 degrees Fahrenheit (15.5 to 20 degrees Celsius), but germination is possible when soil is 40 to 75 degrees Fahrenheit (4.5 to 24 degrees Celsius). High temperatures can trigger thermal dormancy, stalling germination.
Average Germination: Germination depends on temperature and ranges from two days at 70 degrees Fahrenheit (21 degrees Celsius) through one to two weeks at 50 degrees Fahrenheit (10 degrees Celsius).
Thinning Young Plants: When seedlings have grown two or three true leaves, thin crisphead lettuces to 12 inches apart. Other lettuce varieties should be thinned so mini heads are spaced at 6 inches and standard sized heads spaced at 8 to 10 inches. Rows of lettuce plants should stand 18 inches apart for all varieties.
Watering Needs: Water deeply once per week or more often unless rainfall is heavy; increase hydration in times of drought. Aim for soil to remain consistently moist throughout lettuce’s development.
Shelf Life of Seeds: One year
Companion Planting: Lettuce does not struggle against much difficulty with plant diseases or garden pests, so it makes a good companion for many plants. It benefits from shade in the hot part of the summer or neighbors that deter caterpillars, worms, aphids, and other pests that feed on succulent plant life. Lettuce is a good space-saving plant in the garden and can be tucked in between specimens of other plants.
Choosing Which Variety of Lettuce to Grow
Because humans have been cultivating lettuce for such a long time, there are tons of different varieties to choose from when you’re deciding which kinds of lettuce to grow in your garden. If your climate tends toward hot weather, choose heat tolerant lettuces or those that are slow to bolt in hot weather. To prevent problems with lettuce mosaic virus, you can select seeds tested disease-free. These seeds are designated with the letters “MTO-30” on the package, which means the seeds went through testing for lettuce mosaic virus and none was found in a sample of 30,000 seeds.
The many varieties of lettuce plants out there come in five distinct types depending on their characteristics.
Butterhead lettuces are known for their high quality and oily, flavorful leaves, which come from loose heads. Butterhead varieties mature in 55 to 75 days.
Crisphead lettuces, which are so familiar at the grocery store, are the most difficult types of lettuce to grow. Iceberg is an example of a crisphead lettuce. They take 75 days or more to mature and need a long, cool growing season. Any kind of stress can result in bolting; for best results, transplant seeds started indoors into the outdoor garden in early spring.
Looseleaf types grow quickly, within 45 to 60 days, and are known for being easy to care for. Gardeners can start to harvest looseleaf varieties when they have been growing for four weeks for baby lettuce though it takes 45 to 60 days to reach maturity.
Romaine lettuces are also often referred to as cos varieties. They grow in an upright formation, and the shape of the heads is elongated. Some Romaine lettuce heads can reach heights of 2 feet. Romaines come in red or light green and take an average of 70 days to mature. They are more likely to tolerate hot climates and less likely to struggle with bolting than other types of lettuce.
Summer crisp lettuce varieties are also called French lettuces. They fall between butterheads and crispheads in their texture and flavor. Gardeners can wait 50 to 75 days for mature heads to form or can harvest them early as they would leaf lettuce.
Selecting a Location for Growing Lettuce
The most important factor when choosing where to grow your lettuce is the soil. Lettuces need soil that is loose and moist, as their root systems never get very deep. They also need at least six hours of sun each day, ranging up to 10 to 12 hours, although shade is beneficial in warm climates. Keep reading for details on finding the perfect spot for your lettuce bed.
Sun Requirements for Lettuce
For maximum production, lettuce needs to grow somewhere that receives six hours of sun each day at minimum, with 10 to 12 hours of sun each day being beneficial. However, shade is a welcome reprieve from hot weather, especially in the summer. Try to find a place where lettuce plants will get some afternoon shade from trees growing nearby, a fence, lattice, or other structure. If your garden doesn’t have any of these shade options, consider large plants instead, such as beans, corn, kohlrabi, okra, sunflowers, or tomatoes. Shade cloth will also offer a cool shadow where tender lettuce plants can spend their afternoons.
Soil Requirements for Lettuce
Lettuce can tolerate a variety of soil types, loamy being preferred, as long as the pH level is between 6.2 and 6.8. The plants are sensitive to low pH, so if your garden’s pH balance falls below 6.2, use a lime amendment to raise it to the range lettuce can tolerate. Soil should be loose and cool, providing drainage while still retaining plenty of moisture.
Preparing Soil for Lettuce
By improving the soil in fall where your lettuce will grow in spring, you’re making an environment that will result in healthy, tender lettuce plants with flavorful leaves. Use a layer of several inches of rich organic material rich in nitrogen and potassium, such as aged compost, well rotted manure, or a fish emulsion. Mix the amendment down into the top six inches or so of the soil, then rake the top smooth and flat, and leave the soil from fall until spring, giving it time for the organic material to decompose and become one with the soil. Any time you add chicken manure, it’s smart to wait several months (as with this plan, when you’d amend in the fall before a spring planting) to prevent the manure from “burning” your plants with excess nitrogen.
Planting Instructions for Lettuce
You can grow lettuce from seeds or from starter plants procured from a garden center, nursery, or friend’s garden. Seeds can be started indoors early in the season, or you can wait a while to direct sow the seeds into the outdoor garden. For maximum harvest, consider starting some plants indoors and sowing others directly into the outdoor garden or implementing succession planting using the instructions we provide here.
Starter plants should be transferred into the garden as soon as possible after purchase, so wait to purchase your baby lettuce plants until it’s time to plant lettuce outdoors in your USDA Hardiness Zone. If you must wait more than a week or two to move your starter lettuce plants outdoors, you’ll improve their chances of survival and their overall health both short term and long term by moving the baby lettuce plants into larger containers. Simply follow the instructions for planting lettuce in containers that’s listed a few sections below. Then care for the starter plants using our instructions for lettuce plants grown indoors until it’s possible to transplant them into the outdoor garden.
Knowing How Much Lettuce to Plant
Plan to grow lots of lettuce—six to 10 lettuce plants per person who will be eating lettuce will work. Just be sure to renew the harvested lettuce using succession planting. Each 10-foot row of lettuce you plant will yield four to 10 pounds of lettuce in the kitchen.
Planting Lettuce From Seed
To grow lettuce plants from seeds, you can either start the seeds indoors or sow them directly into the garden. When starting seeds indoors, start them six to eight weeks before the last frost date forecasted for the spring. When sowing directly into the outdoor garden, do so as soon as the soil can be worked (or 2 weeks before the last frost date forecasted for spring.) Seeds you start indoors should go into a seed cell tray, with one seedling per cell.
In the garden, plant lettuce seeds at one eighth of an inch deep, arranging them in rows between 12 and 18 inches apart. Thin the seedlings once they each have two or three true leaves to stand 12 inches apart when you’re growing crisphead lettuce or six to 10 inches apart when you’re growing other lettuce types. Light must reach the seeds for them to germinate, so be careful not to plant lettuce seeds too deep.
To grow a lettuce bed or lettuce patch instead of planting lettuce in rows, simply sprinkle the seeds lightly in the area where you want lettuce to grow. Then cover with about an eighth of an inch of fine soil, and press lightly with the palm of your hand to firm the soil. This technique works especially well with looseleaf lettuces, which can grow with up to nine plants per square foot, whereas it would not work for a crisphead variety, which would need the whole square foot to itself.
Planting Lettuce From Transplants
Seeds you start indoors should be left to grow three or four weeks before the seedlings are transplanted to the garden outside. You can transplant lettuce you started from seed and kept indoors or lettuce plants purchased from the nursery or garden center into the outdoor garden once you can work the soil in the garden.
Help lettuce get used to the outdoor weather by using hardening off for three days to gradually increase the amount of time the seedlings spend outdoors. Once they go through hardening off, young plants should be able to survive temperatures as low as 20 degrees Fahrenheit (-6.6 degrees Celsius).
Plants should be spaced 12 inches apart for crispheads and six to 10 inches apart for other varieties in rows that stand 12 to 18 inches apart. Keep dry soil consistently moist so seeds germinate well and to make sure the ground stays cool and damp but not waterlogged. Lettuce will need consistent moisture from the seedling stage until plants are harvested.
Planting Lettuce for Microgreens or Baby Leaves
To grow lettuce that will be harvested at the microgreen stage or as baby leaves to be used in salad, sow more thickly in a band between two and four inches wide. Your seed density should be something close to 60 seeds per foot.
Planting Lettuce for a Fall Harvest
Plant lettuce in midsummer for a fall harvest, following the same instructions as for springtime planting with the exception of the date. When you plan your planting date, work backwards from the harvest date and plan for lettuce to mature close to when the first frost of fall is expected. Although developing seedlings that have been hardened off can usually survive temperatures down to 20 degrees, more mature plants close to their harvest will not be as resilient.
Planting Lettuce for Continuous Harvest Using Succession Planting
Use succession planting by planting new lettuce every one, two, or three weeks from the last frost of spring until the second week in June. This technique will give you a consistently available supply of lettuce to harvest while it is in season. If you plant a few different varieties with varying maturation periods, your selection will be varied as well as prolific. Start the season with early lettuces, grow heat tolerant species for most of the season, and at the end of the summer, begin planting fall lettuces.
Planting Lettuce in Containers
Lettuce grows well in containers because it doesn’t require a lot of room for its roots. However, containers should be at least six inches deep, and you will need the container to have holes in it to provide drainage. The soil in containers heats up more quickly and to higher temperatures than soil in the garden, making it possible for plants to get sunscald on their leaves. They may also have foliage burned where it touches the sides of the container, and in warm weather, containers may not retain water very long. For these reasons, choose containers light in color or paint them white if you garden in a warm region, and avoid those made out of plastic, metal, or terra cotta. Instead, choose clay, coir, concrete, fabric, fiber-resin, glazed ceramic, polystyrene, pressed paper, or wood containers. Place containers in spots that will get at least six hours of sun as well as some shade in the afternoon, and choose larger ones when you can so they will not need water as frequently.
Soil for growing lettuce in containers should be rich in organic material, such as compost or peat. You can add well-rotted manure or additional compost to the soil to make it richer if you like. The soil you use should be loose and loamy, providing lots of drainage. You can treat with a balanced fertilizer, like a granular or water-soluble 5-5-5 or 10-10-10 fertilizer, diluted to half strength, before planting your seeds. Continue fertilizing about every two weeks.
Sow a dense layer of seeds on the soil’s surface, then use your hand to press them gently into the soil. Water the soil well to keep it moist and help seeds say where you placed them. Do not allow the soil to dry out as lettuce plants are developing, but also avoid oversaturated soil. Some people prefer using a spray bottle to keep young lettuce plants evenly misted.
When plants are an inch tall, thin them with clean, sterilized garden shears or clean hands so that leaf lettuces stand four inches apart, Romaines stand six to eight inches apart, and heading varieties are 10 to 12 inches apart. If your containers are not very large, you may thin to just a single plant per container.
When leaves are four inches tall, you can harvest baby leaves for salad, or you can harvest earlier for microgreens. You can also wait through the maturation period for each variety to have completely mature lettuce. For all but heading varieties, you can use cut and come again harvesting. Use clean, sterilized shears to clip off only the leaves you need, starting from the outside base of the plant and working your way inward. Never harvest more than two thirds of a plant’s foliage.
Heading varieties may be pulled up roots and all or clipped to the ground using clean, sterilized shears. Plants you harvest by pulling up from the roots will not keep growing like those you use the cut and come again approach to harvest. To replace these lettuce plants, you can sow two or three seeds or tuck a seedling into the hole the head of lettuce left behind. Plants you cut down to the ground will begin to sprout anew from the remaining foliage.
Planting Lettuce Indoors
You can grow lettuce indoors for a harvest that lasts all year long. Just be sure to situated your lettuce in a south-facing window that gets 10 to 12 hours of sun each day. If you don’t have a spot like this that is draft free and safe from sources of heat, pets, and children, consider using grow lights to plant lettuce indoors.
Loose leaf varieties grow better indoors than heading varieties. Choose containers with good drainage that are flat and shallow or have a diameter of four to six inches. If you will start plants as seeds, use a seed starting mix to replace potting soil in the container.
Start with three or four inches of soil in your container, and water the soil to moisten it. Add your lettuce seeds, at a distance of about an inch apart. Sprinkle a shallow layer of seed starting mix over the seeds. Use a tray or other container beneath your lettuce pot to catch water that flows from the drainage holes, and set your lettuce plants up in the spot you’ve chosen for them. While plants are young, tent plastic over the container to create a greenhouse effect, or use a lid when one is provided.
Make a point of checking your seeds daily for germination. Once sprouting begins, remove the cover or plastic wrap from the container. Use clean, sterilized shears to thin the plants out so they stand one inch apart. Continue keeping plants evenly moist using a spray bottle. Start a fertilizing routine once plants have their true leaves. When three or four weeks have passed and the leaves of your lettuce plants are four inches long, you may harvest them as baby lettuce. Whenever you choose to harvest, cut only the leaves you will use, and new ones will grow in their places.
Regardless of the planting method you choose for your lettuce, unless you’ll be growing your salad greens indoors, it’s worth taking the time just after planting to add a layer of mulch around where your lettuce is growing. Make sure to leave an empty margin around your plants where the mulch does not touch to avoid problems with fungal diseases and rot.The mulch will help moderate the soil temperature, keeping the ground cool when the summer sun is high and hot, and the layer of mulch also offers a good bit of protection from weeds, which will be choked out by the mulch before they can struggle past it to the surface. If slugs are problematic in your garden, however, mulching your lettuce bed may not be the best option for you.
Caring for Lettuce Plants
If cold weather strikes when plants are new, use row covers to shield them from the cold. Row covers can help keep insects at bay as well. In hot weather, use hoops to support row covers to provide plants with some shade. Row covers or cloches should be used to protect plants in a hard freeze.
Watering Lettuce Plants
Aim for a consistent watering routine throughout lettuce’s growth period so plants keep growing throughout maturation. Because lettuce has shallow roots, plants need water moderately but nearly constantly, especially when the weather is hot, so do not allow soil to dry out. Water deeply at least once a week, unless rainfall contributes, adn water more often when drought occurs.
A layer of mulch made from compost or clean straw will aid the soil in staying cool and retaining plenty of moisture. (Just make sure to leave a margin so mulch doesn’t touch lettuce plants). A drip irrigation system is also an optimal solution. As weather gets hotter, plants will require more water, especially those in containers. You can always test the soil to check its moisture level by inserting a finger near where plants are growing. If the ground feels damp or earth clings to your finger, more water is needed.
Make sure to water your lettuce in the cool of the morning or the evening instead of when the sun is high in the sky. Water heated by the sun when the day is at its hottest can burn plant foliage or get so hot as to damage plant cells.
Fertilizing Lettuce Plants
Every two weeks during the growing season for lettuce, fertilize the plants with a balanced water soluble or granular fertilizer diluted to half strength. Find a fertilizer blend that has the three numbers separated by hyphens at equal values, such as a 5-5-5 or 10-10-10 blend.
Harvesting Instructions for Lettuce
Once true leaves have formed and lettuce is four inches tall, you can begin to harvest. Early lettuce is more tasty and delicate than lettuce that’s left in the ground too long. Most lettuces that are not heading varieties can be harvested using the cut and come again approach, and new leaves will grow where the old ones have been taken. Just use clean, sterilized shears or clean hands to pick off the leaves you need, working from the outside base of the plant up and toward the inside. Heading varieties that cannot be harvested this way can either be pulled up at the roots or cut down to the ground. With the latter approach, a new plant will sprout from the foliage left behind.
Grow Lettuce Next to These Companion Plants:
Asparagus (Asparagus officinalis): When the summer sun is too severe for tender lettuces, the asparagus will be tall enough to shade the greens.
Basil (Ocimum basilicum): Basil in the garden benefits the whole area by keeping mosquitoes at bay, but when planted near lettuce, it will improve the taste of the lettuce as well.
Beans (Phaseolus vulgaris): The lettuce’s appetite for rich nutrients will be satiated by the nitrogen that beans infuse into the soil. The taller bean bushes or vines will also give the lettuce some restorative shade in the heat of summer.
Beets (Beta vulgaris): As beets develop underground, they release nutrients into the soil that will be happily drawn in by neighboring lettuce plants.
Borage (Borago officinalis): Borage works as a natural repellent for the tomato hornworms and cabbage worms that can inflict such damage on developing heads of lettuce. In bloom, borage it boosts the whole garden’s well-being by enticing pollinators and other beneficial insects to stop by and visit.
Brussels Sprouts (Brassica oleracea var. gemmifera): Make the most of your limited garden space by sowing lettuce seeds between your Brussels sprouts—or instead of seeds, you can start with baby lettuce plants purchased from the garden center or started indoors earlier in the season.
Calendula (Calendula officinalis): Slugs can make short work of young lettuce plants, but when calendula grows nearby, it distracts the slugs, who prefer calendula to lettuce. Use the calendula as a trap plant (also called a sacrificial plant) in gardens that already struggle with slugs. Gardeners who don’t already see slugs on their property should beware calendula’s potential to draw them in, however.
Carrots (Daucus carota subsp. sativus): When carrot plants blossom, they lure in pollinators and insects that will prey on garden pests. Repay the favor by interspersing your carrots with lettuce plants to keep weeds out of the way so they won’t compete against the carrots for room and resources.
Catnip (Nepeta cataria): Bugs and beetles will stay far away from lettuce when catnip grows nearby.
Chervil (Anthriscus cerefolium): Chervil repels slugs and aphids while encouraging lettuce to grow faster.
Chives (Allium schoenoprasum): Grow chives near lettuce to stave off aphids and Japanese beetles.
Cilantro (Coriandrum sativum): Plant lettuce and cilantro (also called coriander) simultaneously.
Corn (Zea mays): Give lettuce plants some shade when they need it by growing them next to corn.
Dill (Anethum graveolens): Growing dill will keep all kinds of garden pests away.
Hyssop (Hyssopus officinalis): Keep slugs and beetles out of the garden and off your lettuce plants when you grow hyssop.
Kohlrabi (Brassica oleracea Gongylodes Group): While kohlrabi plants throw shade on delicate lettuce, the lettuce repels earth flies from the kohlrabi.
Lavender (Lavandula): Keep lettuce growing healthy and strong by growing lavender nearby..
Leeks (Allium porrum): The carrot flies that can be a problem for lettuce will stay away if you grow leeks close by.
Marigold (Tagetes): Functions as an all-natural pest repellent and attracts hoverflies that eat aphids.
Marjoram (Origanum majorana): Adding marjoram to the vegetable garden keeps all the plants growing strong.
Melon (Curcumis melo): Make the most of the space you have by groing heads of lettuce soaved
Mint (Mentha): Tell cabbage moth and ants to steer clear of the garden whn you grow mint.
Nasturtium (Trapeolum): Attract pollinators and use nasturtium as a trap plant for caterpillars, aphids, and whiteflies.
Okra (Abelmoschus esculentus): Double up to save space and simultaneously keep lettuce plants shaded and cool when you intersperse them with okra.
Pets (Pisum sativum): Lettuce needs lots of nitrogen, and peas fix nitrogen in the soil.
Radish (Raphanus sativus): Use radishes as a trap crop to draw beetles and cucumber away from lettuce. Gardeners also say that the texture of radish is improved when lettuce grows close by.
Sage (Salvia officinalis): Keep slugs and beetles far away from developing lettuce plants when you grow sage near them.
Strawberries (Fragaria × ananassa): Make a protective barrier around strawberry plants by planting lettuce around them.
Sunflowers (Helianthus): Sunflowers reel in pollinators while also shading lettuce and other delicate plants.
Tansy (Tanacetum vulgare): Keep cutworms off your lettuce plants when you grow tansy.
Tomatoes (Solanum lycopersicum): When the weather is hot, tomatoes will give lettuce a break with some shade.
Winter squash (Cucurbita): The shape of winter squash and lettuce plants as well as their timing in the garden means growing them together makes sense.
Troubleshooting Lettuce to Prevent and Treat Common Diseases and Pests
Lettuce is often recommended as a starter plant for beginning gardeners and those who bemoan their lack of a green thumb because it isn’t susceptible to serious challenges from plant disease or insect infestation. However, even the most resilient and vigorous crops will face a problem now and again, and lettuce crops are no different.
When problems do strike, lettuce plants tend to have problems with caterpillars, slugs and snails, and bacterial or fungal rot. To prevent bacterial and fungal disease from striking, use crop rotation to avoid planting lettuce in the same location two years running.