Extension Educator, Horticulture
There is an illness going around. It's called spring fever. It causes people to become giddy over the slightest bit of green in the garden. If you are just itching to see something grow and the mold in the refrigerator just isn't doing it for you then consider planting some lettuce. Lettuce along with peas, spinach, turnip, kohlrabi and kale can be planted now.
Few vegetables are as attractive, tasty and easy to grow as lettuce. The diversity is amazing with colors and shapes of leaves and seed packets often contain a variety.
The trick to good lettuce is cool weather. Lettuce thrives when the average daily temperature is between 60–70°F. At high temperatures growth is stunted, the leaves may be bitter and the seedstalk forms quickly (called bolting). Early spring or late summer plantings are best.
There are five distinct types of lettuce. Leaf (also called loose leaf), Cos or romaine, crisphead, butterhead and stem (also called asparagus lettuce).
Leaf lettuce is by far the most popular in home gardens. It's quick and easy to grow. Cos or Romainelettuce forms an upright elongated head and is an excellent addition to salads and sandwiches. The butterhead varieties are generally small loose heading types that have tender soft leaves with a delicate sweet flavor. Stem lettuce forms an enlarged seedstalk that is used mainly in stewed, creamed and Chinese dishes.
Crisphead varieties or iceberg types so commonly found in grocery stores are adapted to northern conditions and require the most care. In our area they are best started indoors and transplanted in the spring as soon as the soil can be worked. They are extremely sensitive to heat and must mature before the first spell of hot weather. Late summer plantings probably have a better chance of success. I think crisphead is nice for a little crunch in a salad. Alone it reminds me of watery cardboard. Other lettuce varieties offer much more flavor.
Leaf, cos and butterhead lettuce can be planted anytime in the spring when the soil is dry enough to rake the surface. Two or more successive plantings at 10 to 14 day intervals provide a continuous supply of fresh lettuce. Leaf lettuce may be cut whenever the leaves are large enough to use and reaches maximum size in about 50 to 60 days. Other lettuces may take 10 to 20 days longer.
To store lettuce just wash, drip dry and place in a plastic bag in the refrigerator. Lettuce keeps best at 32°F and high humidity (95 percent).
Just a few of the more popular varieties:
Greenleaf - Black Seeded Simpson, earliest to harvest; Oakleaf, resistant to tipburn and good for hot weather.
Redleaf - Lollo Rosso, mild flavor, extra frilly and bolt resistant; Red Fire, ruffles with red edge; Ruby, darkest red of all; Red Sails, slowest bolting of the red leaf.
Cos or Romaine – Cimmaron, unique, dark red leaf; Green Towers, early dark green large leaves.
Butterhead – Buttercrunch, resistant to heat; Nancy, excellent quality and texture; Summer Bibb, resistant to heat and will hold 2 to 3 weeks in the garden; Tom Thumb, delicate miniature heads; Merveille des Quartre Saisons, lovely crispy ruby tipped leaves with a fine flavor and good heat resistance.
Crisphead – Montello, heat resistant; Summertime, adapts well to high temperature and slow to bolt.
Stem lettuce - Celtuce
Sometimes lettuce seeds don't germinate. The cause could be insufficient moisture during germination or old seed. Lettuce seed does not keep well and it is best to buy fresh seed every year. Some lettuce varieties, especially white seeded types, require light for germination. These seeds should not be covered with soil but merely pressed into good contact with the finely prepared soil.