Grow Iceberg Lettuce

Iceberg lettuce, a member of the crisphead variety, grows into dense, compact heads of crisp leaves. While not as flavorful as other lettuce varieties, Iceberg lettuce is the most popular and makes a mild, slightly sweet and crunchy addition to sandwiches and salads. Growing Iceberg lettuce requires cool weather and a long growing season, so starting the plants from seed indoors or purchasing seedlings from a nursery and transplanting outdoors in early spring or late fall increases the chances of a healthy crop.

Steps

Starting Iceberg Lettuce from Seed Indoors

1. Choose a variety of iceberg lettuce. You can order seeds online or purchase them from a nursery or garden supply store.
   • Varieties that are heat-tolerant and fast growing are particularly good for areas that where the temperature rises quickly.
2. Prepare the seed starting trays for planting. Fill seed-starting trays with pre-moistened, sterile seed starting mix, allowing approximately one inch (2.54 cm) of space from the top rim. Gently tamp down the soil so that it is firm in the container, but not hard packed.
3. Plant the lettuce seeds. Place one or two seeds in the center of each section of the seed tray, and gently cover them with a thin layer of the seed starting mix.
   • Iceberg lettuce seeds should be sown approximately four to six weeks before the last day of frost in your area.
   • You can stagger the growth of your lettuce by planting trays one to two weeks apart.
4. Provide water and sunlight. Place the seed trays in a location where they will receive at least six hours of sunlight daily and maintain room temperature. Water the trays with a spray bottle periodically to keep the soil mix moist without flooding it.
   • Until the seeds begin to sprout, you can cover the seed starting trays with a layer of plastic film with small holes punched throughout to help trap moisture and keep the soil warm.
   • The seeds should start to sprout within a week or two.
   • If more than one seed sprouts in each section, thin out the weaker looking plants by carefully pinching them at their base.
5. Prepare the seedlings for transplanting. Once your iceberg seedlings have grown to a sturdy four to five inches (10.16 to 12.7 cm) in height, harden off the plants by placing them outdoors to a wind-protected, shady area for a few hours each day, gradually lengthening the time each day.
   • Hardening off helps prepare the seedlings for outdoor conditions, but be sure to bring them in if temperatures are still dropping below 32˚F (0˚C).

Growing Iceberg Lettuce Outdoors

1. Choose a planting location. Once soil temperatures are above 60˚F (15.6˚C) select an area of your garden that drains well and receives about six hours of sunlight a day.
   • Raised garden beds help keep soil temperatures warmer and improve the growing conditions for iceberg lettuce.
2. Prepare the beds for planting. Water the garden bed well enough to moisten the top six inches (15.24 cm) of soil. Dig planting holes equal to the depth of the seedling tray that are 10 inches (25.4 cm) apart in 20 inch (50.8 cm) wide rows.
   • Add a small spoonful of organic fertilizer or compost to the bottom of each hole and cover it with a small amount of soil to avoid burning the seedlings.
3. Plant the seedlings. Water the seedlings well and then carefully remove them from their trays and place in each hole. Gather the soil around the seedlings and gently tamp down the soil so that they are secure and even with the soil surface. Water the plants thoroughly without drowning them.
   • You can use seedlings that you have grown from seed or purchase seedlings from a nursery or garden supply store.
   • Add a thin layer of organic mulch around the seedlings without letting the mulch touch the seedlings. The mulch will keep the soil moist and cool, and discourage weeds and pests from damaging your seedlings.
   • You may want to trim the outer leaves of the seedlings to help the root system handle the transplanting and growth.
4. Water the Iceberg seedlings. When the top inch (2.54 cm) of soil around the Iceberg seedlings is dry water the plants deeply, usually every five to ten days.
   • Avoid flooding the plants and keep soil from splashing against the leaves during waterings.
5. Care for your Iceberg lettuce. After a few weeks of growing, add a side dressing of organic fertilizer around the base of the plants. Continue to keep the soil moist and ensure that your plants are shaded from the hot, late-afternoon sun as the season goes on.
   • Remove pests such as slugs and snails by hand or use an organic deterrent.
6. Harvest your Iceberg lettuce. When the heads are fully formed and firm, and before temperatures rise above 75˚F (23.88˚C), carefully cut the plant at the base with a sharp knife and remove the entire head.
   • Harvest the lettuce heads in the early morning when they are firmest.
   • Begin harvesting when lettuce heads are just larger than a softball, usually about two to three months from planting, and stagger your harvest so that you are only harvesting one or two every week or so.
   • The inner leaves may feel slightly loose and appear light green, but the inner leaves should be tight and firm.

Tips

• You may need to use floating row covers or other shade protection to avoid too much late afternoon heat and sunlight that could cause the lettuce to bolt.
• Monitor the temperatures in the garden to make sure your lettuce doesn’t bolt from too much heat or sunlight.
• Stagger your growing and planting schedule to ensure a steady supply of Iceberg lettuce throughout the growing season.

Warnings

• Grow your Iceberg lettuce during cool months of the year when temperatures are below 75˚F (23.88˚C), and make sure they are well shaded to keep them from bolting, which ruins their flavor.

Things You’ll Need

• Iceberg lettuce seeds or seedlings
• Seed starting trays
• Seed starting soils
• Organic fertilizer and/or compost
• Gardening trowel
• Gardening gloves
• Row covers
• Spray bottle
• Sharp knife

Related Articles

• Keep Lettuce Fresh
• Grow Lettuce Indoors
• Grow Hydroponic Lettuce
• Grow Organic Lettuce
• Plant Lettuce

Sources and Citations

See also

• Plant Lettuce
• Grow Lettuce Indoors
• Grow Hydroponic Lettuce