Botanically known as Lactuca sativa, the lettuce is a biennial plant of the sunflower family Asteraceae. Among the greens, lettuce leaves are valued for its low calorie content and an excellent source of vitamin A and folic acid. They also contain Lactucarium, a very opium-like substance that is known to induce sleep, but to get that effect, one needs to eat lots of lettuce! Its name has been derived from the Latin word lac, which means milk, in reference to the plant's milky juice.
Lettuce plants grow as a rosette of leaves on the ground on a short stem. Depending on the cultivar, a lettuce plant will mature as a head or leaf with the leaves and stem lengthening. Some leaves will shape as a closed head, while some grow upright, with the leaves arranged in an elongated, loose head fashion. Lettuce produces many small dandelions lookalike flower heads. The types or cultivars include butterhead, Chinese lettuce, iceberg (crisphead), Romaine (cos), etc. Certain cultivars were introduced to remove the bitterness from their leaves. This is done by adding more water content to the variety. However, lettuce that is high on water content has very little nutrient value, whereas the bitter or darker ones contain a high level of antioxidants.
A favorite among vegetable gardeners, lettuce is fairly easy to grow. One of its best features besides being a seasonal crop, is that it doesn't take a lot of space and has shallow roots, which makes it well suited to container gardening. Follow these tips to ensure a healthy and abundant yield.
The most popular method used to grow lettuce is with the help of seeds. You may either harvest them from last year's good crop, or buy them from a reputed vendor. It is preferable to sow seeds in containers than in the ground. Use sowing medium that is moist, yet not water retaining, and has a good composition of organic compost. Sprinkle seeds five inches apart in rows that have been spaced out by four inches. Mist the sowing mixture regularly until you see the seeds sprout. Once the seedlings begin to appear, acclimatize the container to more sunlight. Sow seeds in spring or early summer.
Planting and Watering:
Once seedlings have developed strong roots and shoots, about six true leaves, you can thin them out. Prepare the garden area or container before you begin to transplant. This will ensure that the roots aren't exposed for a long duration. Lettuce should be planted 2-4 weeks before the last frost date, and/or about 6 to 8 weeks before the first frost date. Select a location that receives at least 5 or more hours of sunlight a day. Till the soil well to make a vegetable patch. Growing lettuce in raised bed vegetable gardens will also produce good results. Add a good quality organic compost and some fertilizer to the soil. Plant each seedling about four to six inches apart in rows spaced out by four inches. Water the lettuce well, although they need a good level of moisture, as the roots are shallow. However, don't over water them. Excess water will rot the roots, while less water will stunt their growth and make the leaves bitter. If you want to grow lettuce indoors, then follow the same soil and water considerations, except that it would need less water and should be placed in a spot that receives enough sunlight.
If lettuce is planted in soil that has been well fed with rich organic compost, fertilization is not needed. Appropriate quantity (as per package directions) and timing (just once in its entire growing season) will ensure a good harvest. As it is a green vegetable, pest attack is unavoidable. Being voracious eaters, caterpillars, cabbage worms, loopers, aphids, and armyworms can destroy the entire crop. Diseases like anthracnose, bolting, damping off, mildew, viruses, and leaf spots too can damage the plant. As it is meant for consumption, it is really not a very good idea to spray it with a lot of pesticides, however, the pest and diseases need to be gotten rid off. You may use herbal-based insecticides specifically made for home use.
Growing organic lettuce involves absolutely no use of any chemical fertilizers or pesticides. Harvesting it depends upon the type that has been planted. Head lettuce is harvested when the head becomes firm, whereas the leaf lettuce should be harvested when the leaves have just opened up from its loose head. One must make sure that it is harvested before it begins to bolt. Bolting is the formation of flowers and seeds due to high temperatures which makes the leaves bitter. To get a steady flow of lettuce greens, plant them in succession.