How to Plant, Grow, and Care for Iceberg Lettuce in Your Garden
Iceberg Lettuce is one of the most common vegetables used around the world. Due to it's extreme popularity, many gardeners look to add them to their own garden. In this article, organic gardening expert Logan Hailey walks through every step you'll need to follow in order to plant, grow, and care for iceberg lettuce in your garden.
Iceberg lettuce isn’t the trendiest or sexiest vegetable by any means. In fact, it’s been the brunt of many jokes in recent years for its bland, pale leaves slathered in fast food salad dressing. But garden-grown lettuces have historical roots far more interesting and palatable. In fact, the cultivation of lettuce goes way back to ancient Egypt and was even pictured in early Egyptian tomb paintings along with the god of fertility.
The leafy crisp green has been ubiquitous in salads and even herbal medicine for thousands of years. Iceberg types are a more recent breeding innovation from the 1920s, which have been continuously improved by small garden seed companies in recent decades. Iceberg lettuce is easy to grow, full of nutrition, and far more delicious than the tasteless, watered-down industrial types.
Given its bad reputation in modern times, there’s lots of reasons to grow your own lettuce. For one, garden grown iceberg lettuce is way more nutritious. You can also be sure that it hasn’t been treated with any toxic pesticides so common in conventional lettuce farming. Furthermore, it is way more flavorful. There are many garden iceberg varieties that are so loaded with flavor and texture that you’ll be surprised they’re even related to that bland wedge salad at a chain restaurant.
It’s time to upgrade your salads and sandwiches with crisp lettuce grown straight from the garden. Let’s dig into how to plant, grow, and care for this infamous hydrating salad green.
Iceberg Lettuce Overview
Plant Type Annual
Plant Family Asteraceae
Plant Genus Lactuca
Plant Species Lactuca sativa
Hardiness Zone USDA 1 to 11
Planting Season Spring or Fall, cool-weather
Plant Maintenance Low
Plant Height 6-12”
Fertility Needs Low
Temperature Cool, 50-65°F ideal
Companion Plants Tomatoes, peppers, onions
Soil Type Well-drained
Plant Spacing: 12-18”
Watering Needs Moderate
Sun Exposure Full sun to partial shade
Lifespan: 50-70 days
Pests Caterpillars, slugs, birds, deer
Diseases Downy mildew
History and Cultivation
Iceberg lettuce is one of the most popular types of lettuce grown in the United States. While many cool-weather lettuces cannot handle warm conditions, iceberg lettuce tolerates some heat as well as some cold.
Though most of it is grown in California, it is in fact a widely adapted crop that can be grown in gardens from USDA zones 1 to 11. It also has a fascinating history dating all the way back to ancient Egypt.
What is Iceberg Lettuce?
Iceberg lettuce is an annual vegetable variety of crisp head lettuce known for its pastel green leaves, white interior, and cabbage-like shape. Like all lettuces, it is a member of the Asteraceae or daisy family. The many layers of ruffles and ripples inside the lettuce heads make it attractive for many types of salads, and the large textured leaves taste great layered into sandwiches.
Iceberg lettuce got its name from the way the lettuce was originally packed and transported when it first became popular in the 1920s. Produce companies would cover the heads in crushed ice, making them appear like little icebergs as they made their way via trains to grocery stores around the country. The mainstream variety is actually called ‘Imperial’ or ‘New York’ and is quite bland compared to unique garden cultivars available in seed catalogues.
Today, this veggie is found in grocery stores and restaurants everywhere. You could almost call it the “all-American head lettuce” because it is such a ubiquitous backdrop for the classic flavor of cheeseburgers and wedge salads with blue cheese dressing.
Given its neutral and mild flavor, it is mostly cultivated for its juicy, crisp texture. It is one of the easiest lettuces to grow because it tolerates warmer conditions without bolting like other lettuces. It also packs a tender hydrating crunch for some of the best summer salads you’ve ever grown.
Where Does Iceberg Lettuce Originate?
Lettuce (Lactuca sativa) has been cultivated in gardens and on farms for millenia. It is undoubtedly the world’s most popular salad crop and can be found in just about every cuisine on the globe. While cultivated lettuce has its origins from wild lettuce (Lactuca scariola) in the Middle East and parts of central Asia, it has come a long way since its cultivation in ancient Egypt, Chinam, Greece, and Rome.
The Latin genus name Lactuca comes from the root “milk” which refers to the milky latex-like sap found in lettuce stems and seeds. The word lettuce likely comes from the old French word “laitues” which means “milky”. But most of us never see the milky part of lettuce when it is cut from the base, instead we find the crisp green frilly leaves in our salads.
Lettuce was especially popular amongst Egyptians, who associated that milky sap with lettuce’s alleged ability to improve sexual performance and stamina. The Romans also associated lettuce with sexual potency and consumed the less-bitter leaves in salads with vinegar and oil as a pre-digestive appetizer for meals.
In China, lettuce was often consumed as “stem lettuce” stalks similar to celery, until later when looser leafed head lettuces were developed through natural breeding efforts. By the 16th century, Europeans had improved firm-heading types that grew more as compact rosettes with less bitterness. Colonists brought the lettuce to the New World via the Bahamas in the late 1400s and was one of the first seeds sown by early gardeners in America.
Is There Any Nutritional Value?
Contrary to popular belief, it does have nutritional benefits. Though it is about 95% water, it is a super low-calorie vegetable that can be a source of vitamins A and C, calcium, iron, and some trace minerals like magnesium, potassium and folate.
While it isn’t as jam-packed with nutrients as famous greens like kale and spinach, iceberg lettuce is still extremely hydrating and improves gut health with fiber and prebiotics. It is an excellent aid for weight loss and also a crisp, refreshingly neutral flavor for any salad.
Iceberg lettuce is grown very similarly to other lettuces and is easily propagated by seed. If you don’t have a seeding setup, you can also purchase lettuce starts from a local garden store or nursery to get a head start on your lettuce-growing season. It is particularly popular amongst beginner gardeners because it germinates easily in cool spring weather and matures in less than 2 months.
Lettuce is remarkably hardy and the seeds can germinate in soils as cold as 40°F. However, it does not germinate in hot soils about 75°F. In fact, hot weather can cause lettuce seeds to go dormant, so avoid storing the seeds in a warm place. So store the seeds in a cool, dry place and prepare to sow them in trays indoors or directly in the garden in the early spring.
I recommend sowing lettuce in successions every 2-3 weeks for a continuous supply of crisp salads throughout spring and early summer.
How to Seed Iceberg Lettuce
Prepare seed trays with a high quality, well-drained seed starting mix about 3-4 weeks before planting out. I prefer to use 6 packs or 72-cell trays. As you fill the cells, be sure not to tamp down or compress the mix too much, as lettuce seeds are very small and need plenty of aeration to germinate.
Sow 2-3 seeds per cell very shallowly on the surface (about ⅛” deep), only lightly covering with a dusting of the mix on top. They can benefit from a little bit of light to germinate. Gently water and keep trays consistently moist for 7 to 10 days until germination. The ideal germination temperature for lettuce is 55° to 65°F. Once the lettuce seedlings have 1-2 true leaves, it is important to thin them to one seed per cell to ensure each plant has enough room to mature.
How to Direct Seed
You can also seed lettuce directly into your garden in the early spring. This is most commonly done for baby leaf lettuce, but you can also direct seed iceberg heads if you’d like. Sow seeds in cool soils about ⅛” deep and firm gently into the ground. For iceberg heads, sow 15-18” apart in rows 12-18” apart. For baby leaf lettuce, sprinkle 4-6 seeds per inch in bands about 2” apart.
Keep consistently moist and use row cover to keep birds and rodents out of the seedlings. You need to pay extra attention to irrigating dry or hydrophobic soils to ensure plenty of coolness and moisture for uniform germination.
Lettuce is a hardy annual cool-weather crop that can be planted while night time temperatures are still frosty. This veggie often one of the very first crops in the spring garden as well as a perfect late fall salad ingredient. It’s also cold hardy and can be transplanted as early as 2-3 weeks before the last frost date, or as soon as the soil can be worked.
Iceberg lettuce should be hardened off for 3 to 5 days before planting to allow them to acclimate to more extreme outdoor weather. If young plants are properly hardened, they can handle down to 20°F in the garden.
How to Transplant Iceberg Lettuce
Once you have thoroughly hardened off seedlings (by moving them to a sheltered area outside of your home or nursery), you are ready to transplant into the garden. Begin by preparing a garden bed with loamy, well-drained soil and a generous helping of compost. Rake it flat and mark out a grid with rows approximately 10-12” apart and holes for the lettuce plants about 15-18” apart.
Use a hori hori planting knife or garden trowel to make a hole the size of your seedling cells. Gently wiggle the plants out of their cell trays and place in the soil without disturbing the roots. Backfill gently without compacting the soil, and water thoroughly at establishment. Iceberg lettuce can be a magnet for hungry birds and deer, so I prefer to protect young plantings with row cover until they are established.
How to Grow Iceberg Lettuce
Iceberg lettuce is truly one of the easiest greens to grow in your garden. It’s right up there with cucumbers or zucchini. As long as you avoid planting it during the hottest months, it will gladly yield for you with very little effort.
Lettuce does best in full sunlight to partial shade with at least 6 hours of sun per day. If growing in the summer, lettuce can benefit from slightly more shade to keep it cool and prevent it from bolting. Iceberg lettuce is more resilient to warmth than other types, but still enjoys a bit of afternoon shade to prevent the leaves from getting scorched.
Lettuce is a great companion crop alongside taller, slower-growing plants like tomatoes and peppers, because they keep the soil covered while harnessing the unused space of your garden. Just be sure that the lettuce is planted at the same time as the tomatoes so it matures before the tomato plant fully shades it out.
Lettuce is not very drought tolerant due to its shallow root zone. It should be mulched with compost or clean straw to retain moisture, and then watered deeply at least once a week if there is not any rain. It is best to use drip irrigation or soaker hoses to prevent splashing a bunch of dirt into the lettuce heads with overhead irrigation.
In times of intense sunlight or heat, lettuce is especially thirsty and can quickly dry out. Check the soil regularly by sticking your finger in near the base of the plant. If your skin comes out clean and the top 2-3” are dry, you need to thoroughly water the lettuce bed.
Honestly, lettuce isn’t super fussy about the soil type. Like most garden vegetables, iceberg lettuce really enjoys a nice well-drained soil but will still grow in less-than-ideal conditions. The most important thing is cool soil temperatures.
Drainage and a bit of sandiness tend to be helpful, but I have found that lettuce will also tolerate heavy clay soils and even a bit of compaction. This is probably thanks to its shallow root zone and quick growth habit. Regardless, I always mix quality compost into my garden beds before planting to give me the best chance at success with all of my crops.
Climate and Temperature
Iceberg lettuce is a cool weather crop that thrives best in temperatures between 50 to 65°F. It loves the cool nights of northern climates. If properly hardened off and established, the plants can handle hard frosts down to 20°F, but may have some leaf damage.
Depending on the variety, lettuces tend to bolt and go to seed in conditions over 75°F. This is why it’s important to select bolt-resistant varieties (especially for southern climates) and avoid planting in peak summer heat.
Like many garden crops, lettuce tends to be more bitter and less tender when it is under heat stress. The sweetest, crispest lettuce will undoubtedly come from spring and fall production, or winter greenhouse growing.
Lettuce is a notoriously light feeder that can often just feed off of any nutrients hanging out in your garden soil. Since I like to incorporate lettuce as a companion planting or rotational vegetable between other heavy feeders, I usually just let it pick up the residual fertility of other crops.
If your soil is exceptionally poor, you can fertilize lettuce with diluted all-purpose organic fertilizer or a diluted kelp emulsion at planting. Avoid fertilizing the leaves directly with fish or kelp once the plants are larger because it can be difficult to fully rinse off.
Lettuce requires little maintenance aside from regular weeding and irrigation. If a heat spell comes, sometimes I’ll toss some shade cloth over the lettuce patch to keep it from bolting.
Iceberg lettuce is most commonly harvested by the whole head rather than “cut and come again” like oak leaf or frilly lettuce types. Once the plant has thoroughly headed up into a dense round ball, use a sharp garden knife to cut right at the base and keep the wrapper leaves intact.
Wash off the milky sap right away and dunk in water for the longest storage capacity. Iceberg lettuce likes to be dried on paper towels or in a salad spinner to prevent premature spoiling.
Most people don’t realize that iceberg is actually just a generic name for crisphead lettuces. Crisp head means that the lettuce forms more of a ball like a cabbage, rather than growing with outward frills like a leaf lettuce. There are dozens of different varieties of crisphead lettuces, some of which are adapted to hot southern climates and others that really prefer the cold.
Best Varieties for Flavor:
- ‘Crispino’: An organic classic iceberg type with glossy green, firm round heads that have a white interior and juicy, mild flavor. This iceberg is widely adaptable and tolerant of less-than-ideal conditions. 57 days.
- ‘Saladin’: Sweet, crisp, and refreshing classic iceberg that has tightly-wrapped dense heads perfect for wedge salads. The leaves are dark green and tinder on the edges and thicker and paler toward the center. Bolt resistant, downy mildew resistant, and great for summer growing. 62 days.
Best Varieties For Hot Weather:
- ‘Leda’: A crunchy crisphead that is tender and forms large, round, dense heads. Light green leaves with a nice sweet flavor. Very slow bolting for hot summers. 60 days.
- ‘Saragossa’: This vibrant green and red crisphead doesn’t create as much of a round “ball” as traditional icebergs, but it is crisp and sweet nonetheless. ‘Saragossa’ is one of the most heat-resistant crisphead types that is compact yet with an open habit for harvest at any stage. 45-55 days.
- ‘Red Iceberg’: Speckled burgundy and green, this iceberg is resistant to mushiness in hot weather. Heads are compact, medium sized, and bolt resistant. 63 days.
- ‘Igloo’: This strongly heat-resistant iceberg grows cool, crispy heads fairly quickly without bolting. Holds well in the garden and tastes pleasingly mild with a nice classic green color. 70 days.
Best Cold Hardy Varieties:
- ‘Gildenstern’: A vibrant green mini-iceberg lettuce that yields tightly wrapped 4” whorled heads perfect for single serving salads. Perfect for cold early spring plantings as well as late fall. 46 days.
- ‘Iceberg A’: One of the original iceberg heirlooms from 1894, this great American lettuce is firm, crunchy, and crisp. It produces cool-green medium-sized heads that are the most similar to store bought icebergs. Thrives in cool weather. 85 days.
Pests and Diseases
Lettuce is remarkably resilient in the garden and doesn’t tend to have many issues on a home-scale. Caterpillars, slugs, deer, and birds are your biggest potential enemies. Downy mildew can also be a problem in exceptionally damp areas.
Caterpillars are the most damaging of lettuce pests. They come from a wide range of butterfly or moth species that lay eggs near your lettuce plants. Each type has a different feeding pattern, but they all ultimately result in the same damage: mangled, lettuce leaves full of gnarly holes.
Hand picking is the easiest option in a small garden. Planting white alyssum, yarrow, or dill can be a great way to attract natural predators like parasitic wasps. Worst case scenario, you can use Bt (a biological organic pesticide that is made from a soil bacteria) to get rid of caterpillars on your lettuce.
Slugs are the slimy, fat, annoying pests that really take hold in excessively moist conditions. They can hide under mulches or just slime around in extra humid weather. Sluggo is one of the simplest organic options for killing slugs. You can also sprinkle diatomaceous earth around the base of your lettuce plants, but you will need to reapply after a rain.
Deer and Birds
Deer and birds love crisp, tasty lettuce as much as we do. I’ve found that these are the most common predators of iceberg lettuce in the garden. The easiest way to get rid of them is to exclude them altogether with a row cover (a thin light-transmissible fabric laid over the crop).
You can also use an outdoor cat or dog to repel deer and birds. Blood meal (a granulated organic fertilizer) is another option for sprinkling on garden margins to repel deer, however a tall fence is the most reliable long-term option in deer-prone areas.
Downy mildew is the main pathogen that attacks lettuce. It is a fungus-like organism that causes yellowing patches and white fuzzy mold. It loves excess moisture, especially from overhead irrigation, which is why I always recommend watering iceberg lettuce from the base.
Downy mildew can get into lettuce heads and ruin them from the inside-out, so if you live in a very moist climate, consider planting downy mildew resistant varieties and increasing spacing between plants for more airflow.
Iceberg lettuce is grown specifically for the tasty, tender round heads that are coveted for wedge salads, sandwiches, and hamburgers.
Frequently Asked Questions
How do you care for iceberg lettuce?
Luckily, this vegetable is very easy to grow and care for. Simply plant in the spring as soon as the soil can be worked or in cool fall weather. Grow in full sun to partial shade, with soil that is well-drained, consistently moist and weed free.
How do you take care of a lettuce plant?
Lettuce is a remarkably beginner-friendly vegetable crop that requires very little care. Seed or transplant in well-drained cool temperature soils and provide consistent moisture throughout its lifecycle. Be sure lettuce gets full sun or partial sunlight for at least 6 hours a day. Keep beds weeded and protect lettuce from birds or deer feeding on the leaves.
How often should you water iceberg lettuce?
Iceberg lettuce is a moderately thirsty crop that needs to be deeply watered at least once a week if there is no rain. Drought stress can lead to bitter, tough leaves. Use the “finger test” in the top couple inches of soil to check moisture. If your finger comes out clean and dry, it is time to water. It may also wilt in the heat of the day if it is thirsty.
Iceberg lettuce gets a bad rap amongst many health foodies, but they don’t realize that garden iceberg is an entirely different beast than its industrial counterparts. This crisp, mild, dense lettuce is the perfect addition to summer salads and can actually be loaded with nutrition when grown in your healthy organic garden soil.
Plus, it’s so simple and rewarding to grow. Next time you hear someone roll their eyes about iceberg lettuce, you can offer them a taste from your garden and change their mind right away!