Crisphead Plant Info – Growing Different Crisphead Lettuce Varieties

Crisphead Plant Info – Growing Different Crisphead Lettuce Varieties

By: Bonnie L. Grant, Certified Urban Agriculturist

Beautiful, crunchy salad greens right from the garden are an almost year around treat in some regions. Crisphead lettuce varieties offer greens with a nice toothy, snap and sweet flavor that complements any dressing. What is crisphead lettuce? You may recognize crisphead lettuce plants as the commonly sold iceberg lettuce found in your produce market. Versatile and easy to grow with a little know how.

What is Crisphead Lettuce?

Crisphead lettuce is mostly grown in cooler, northern climates. It needs a bit more maintenance than the loose-leaf varieties but has a characteristic flavor and texture not found in those types. They bolt in summer but can be started in fall or early spring, producing at least two seasons of produce. They also, need a longer growing period as compared to the upright or loose-leaf varieties. Some crisphead lettuce info will help you navigate this more picky but definitely worth growing head lettuce.

Crisphead, or iceberg, is a rounded, compact lettuce with overlapping leaves. The interior leaves are paler and sweet, while the exterior, greener leaves are more malleable and useful for lettuce wraps. The plants need a long, cool season to develop the dense heads. In areas without such weather, they should be started indoors and transplanted outside while temperatures are still cool. Plants growing in summer will generally bolt and get bitter.

Crisphead lettuce plants are favorites of slugs and snails as well as other pests and need constant vigilance to prevent leaf damage.

Growing Crisphead Lettuce

The best way to ensure thick, round heads is to start the seed indoors in flats or outside in cold frames. Temperatures of 45 to 65 degrees Fahrenheit (7 to 18 C.) are ideal for growing head lettuces.

Harden off transplants and install them in a bed with loose, loamy soil and plenty of organic matter. Space them 12 to 15 inches (30 to 38 cm.) apart. Use an organic mulch around the plants to conserve moisture and prevent competitive weeds.

Crisphead lettuce info recommends frequent but light watering, which will promote the growth of the leaves. Make sure the area has good drainage to prevent mildew and fungal problems. Use iron phosphate around the bed to prevent snail and slug damage.

Crisphead Lettuce Varieties

Some of the head lettuces have been bred to be more heat resistant and/or slower to bolt. These varieties should be selected in areas with short spring cool temps.

Ithaca and Great Lakes are suitable for these climates. Igloo is another great heat resistant type. Crispino forms medium sized, light green heads. Iceberg A was introduced in 1894 and develops large deep green heads. A slightly looser head is produced by Red Grenoble, with fluted leaf edges and attractive bronze, red blush tones.

Harvest heads when compact and firm. Use them in wraps, salads, sandwiches or just as a crispy snack.

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How to Grow Crisphead Lettuce | Guide to Growing Crisphead Lettuce

Iceberg lettuce grows in small, dense heads. Commonly used in salads and sandwiches, they are prized more for their texture and crispiness than for the flavor of the leaves themselves. Iceberg was first cultivated in the Salinas Valley of California, then packed in ice and distributed across the US on trains, earning its namesake. Space plants 12" apart with 18" between rows.

Growing Guide

Lettuce grows best in full sun, though excessive heat can cause plants to bolt to seed, or leaves to wilt. For an early start, seeds can be started in flats 4 weeks prior to the last frost and transplanted outdoors in mid to late spring. If growing in summer, select a partially shaded location, or one that receives primarily eastward exposure to mitigate the potentially damaging effects of excessive heat upon lettuce.

Lettuce is tolerant of a wide range of soils, but prefers well-drained, cool, loose soil with plentiful moisture and pH 6.2 to 6.8. Sensitive to low pH. Lime to at least 6.0. To encourage tender and tasty growth, make sure location is rich in organic compost matter. Amend prior to planting if needed.

Direct seed or transplant in early spring, as soon as you can work the soil. To get an early start, prepare beds the previous fall by working in manure or compost and raking smooth to leave a fine seedbed. Seeds need light to germinate sow at a very shallow depth by covering with a thin layer of growing medium.


Sow seed 1/8 inch deep, 1 inch apart in rows 12 to 18 inches apart. When plants have two or three true leaves, thin to 12-inch spacings for crisphead varieties, 6 to 10 inches for other types. You can also lightly broadcast seed (particularly of looseleaf varieties) in a patch instead of a row.


Sow in 1-inch cells 3 to 4 weeks before transplanting outside. Harden seedlings by reducing water and temperature for 3 days before transplanting. Hardened plants should survive 20 F. Space crisphead transplants 12 inches apart in rows 18 inches apart. Space other varieties 6 to 10 inches apart in rows 12 to 18 inches apart.

Use row covers to protect very early plantings from cold, to protect young plants from insects, and (supported by hoops) to shade crops when warm weather arrives.

Make succession plantings every week or two, and grow several varieties with different maturity dates for a continuous supply. Moisture, stress, and high temperatures, particularly at night, encourage bolting. As the season progresses, plant more bolt-resistant varieties. Locate plants where they will be partially shaded by taller nearby plants, latticework or other screen.

Lettuce has a shallow root system. Keep soil moist to keep plants growing continuously. Mulch to retain moisture and suppress weeds (unless slugs are a problem). Fertilizing can be helpful to promote faster growth, especially a fish emulsion type that is not high in nitrogen that can cause greens to become bitter. Water lightly but consistently.

For fall crops, time maturity around time of first expected frost. Mature plants aren't as tolerant of freezing as seedlings.

Heirloom seeds are the gardeners choice for seed-saving from year-to-year. Learning to save seeds is easy and fun with these books. Before you harvest, consider which varieties you might want to save seeds from so that your harvesting practice includes plants chosen for seed saving. Be sure to check out our newest seed packs, available now from Heirloom Organics. The Super Food Garden is the most nutrient dense garden you can build and everything you need is right here in one pack. The Genesis Garden s a very popular Bible Garden collection. The Three Sisters Garden was the first example of companion planting in Native American culture. See all of our brand-new seed pack offerings in our store.

Many varieties of lettuce can be harvested as microgreens, baby greens, leaves, or entire plant. Ideally, greens should be collected early in the day, before the onset of midday sun, to prevent wilting.

Microgreens are usually harvested within 2 weeks after germination by cut entire plant just above the ground, once it is around 3-4" tall.

Baby greens are collected when between approximately 28-35 days after germination, and are collected. Looseleaf, butterhead and romaine types can typically be harvested as baby greens, while iceberg lettuce is not suitable as baby greens.

'Mature leaves' can be harvested from all type of lettuce except for iceberg any time in the growing cycle, until a central stem begins to form. This indicates the plant is preparing to bolt to seed, and greens collected from such plants are often too bitter for consumption.

Entire plants can be harvested in mid-development while the leaves are still plump and tender, but before a stem has started to form. Many varieties of looseleaf lettuce can be harvested numerous times during a single growing season after being cut approximately 1" above the ground.

Some other general guidelines when collecting the entire plant:

Leaf lettuce can be cut as soon as it is large enough to use, usually in 50 to 60 days from planting. Cutting every other plant at the ground will give remaining plants more space for growth.

Romaine and Butterhead lettuce can be harvested in about 60 to 70 days from planting.

Iceberg (crisphead) varieties take longer and should be harvested as soon as a head develops but before outer leaves turn brown. If seed stalks appear, pick the lettuce immediately and store in the refrigerator to prevent bitterness. To store lettuce first wash it well by immersing in water and swishing it around. Place it in a colander and rinse then drip dry. Do this especially if you have used chemicals on your crop. When it is dry place it in a plastic bag in the refrigerator or wrap in paper towels and place in a bowl in the refrigerator. It keeps best at 32 degrees with 96% humidity. Avoid storing lettuce with apples, pears or bananas as they release a natural ripening agent that will cause brown spots and the leaves will decay quickly.

Rubbing separates the plumes and chaff from the seeds. When completely dry, shake the flower stems in the bag. Rub the seed heads between your hands to release more seeds. Put the seed through a fine mesh sieve that allows the seeds through but retains the chaff and plumes this will give relatively clean seed. Winnowing is difficult because seeds and chaff are about the same size and weight. For extra cleaning use reverse screening, with a smaller mesh that retains the seed but lets small pieces or chaff and plume through. The dust produced during cleaning causes irritation to the lungs and eyes. If cleaning large amounts use a mask and goggles or clean outdoors.

When to Harvest Lettuce:

Start harvesting Leaf lettuce once the plants are 5-6 inches tall.

Harvest Butterhead lettuce when the leaves start to form a loosehead. Whereas for Romaine lettuce, wait till the leaves become large enough to overlap and form a fairly tight head. This usually happens once the plant reaches a height of 6-8 inches.

Harvest Crisphead lettuce when the leaves overlap to form the head. As the name suggests the lettuce head will be firm and compact.

The best time to harvest lettuces is in the morning at this time lettuce will be the crispiest.

Harvest with a knife. If the variety forms head cut it right below the head and separate it from the stem. If it’s not, harvest the leaves from the outer side of the plant and leave the central core intact. This way, you will have a continuous supply of lettuce.

You can harvest both the older or matured, and the younger or tender leaves. Older, outer leaves are high in calcium. The immature tender leaves taste best with the salads.

Nutritional Value of Lettuce:

Lettuce has good nutrition value and is very beneficial for your health. Green leaf lettuce is a good source of vitamins A, C, K, and folate. It also has manganese and certain phytonutrients.

Lettuce is a popular ingredient in salad, worldwide. Before consuming lettuce rinse it in clean cold water.

Don’t cut lettuce leaves with knives it will make the edges turn brown. Instead, tear the leaves into pieces with hands.

The soil in raised beds and containers tends to warm up faster than traditional in-ground gardens. These warmer soil temperatures can give gardeners an earlier start in the spring and extend the growing season later into the fall, providing opportunities for more crop successions. In addition, raised bed or container gardening allows gardeners to control the soil quality better and provide the rich, loose, well-draining soil that lettuce plants crave.

Lettuce can also be grown in the ground, as long as the soil is well-tilled and amended with nutrient-rich soil that is free from rocks and debris.

Watch the video: How to Grow Quick Late-Season Salad Crops