As with all vegetable gardening, good soil is a must. Keep the nitrogen level high by the use of a good 30-10-10 NPK (nitrogen, phosphorous, potassium) fertilizer. That gives them lots of nutrition for producing healthy leaves.

Plant the seeds about 1/8-3/8 inch deep, separated by 6-12 inches (2-3.5 m) from the next plant. Romaine does fine at the smaller spacing, but crisp lettuce needs more room. If you plant in rows, keep the rows separated by about 20 inches (6m). Keep in mind that seeds shouldn't be planted too early, since they're subject to cold damage.

The roots of lettuce do not grow very deep so it is important to weed often. Many other grasses and plants with deeper root growth can invade the lettuce.

Since their roots aren't very deep you'll also need to be diligent about weeding around lettuce plants. Many grasses and other plants can compete well because their roots go down to deeper soil. Infrequent but deep watering, letting the top layers dry out, will give most an advantage. But lettuce doesn't have that advantage, so you'll need to help them.

Like most vegetables, lettuce plants also have problems with diseases and pests. In their case, the variety is quite large. Many insects find the leaves irresistible and the folds offer many places for fungi to grow.

Aphids, flea beetles, leafhoppers, slugs and cutworms are common insects that feast on lettuce. Washing the leaves with a high-pressure hose can temporally help get rid of the insects. Insecticide lightly applied to the lettuce will provide better long-term control.

One common fungal disease is anthracnose (Microdochium panattonianum). This fungus can stay alive in soil for many years. Bottom rot (Rhizoctonia solani) is another common fungus. This type of fungus usually occurs in soil that drains poorly. To combat these fungi, keep foliage dry and plant in good soil.

Bolting is a common problem with lettuce, and it isn't a disease or pest, though it can be worsened by them. It occurs when the plant goes to seed and the leaves stop growing. Lettuce likes cool weather and bolting is more common when the temperatures are consistently too high. Keeping the plants shaded will help. One way to do that is to plant a shading crop, like corn, over the lettuce.

With the proper preparation, planting technique and care you can have lettuce several times during a growing season.