Growing lettuce in raised beds is a fast method for harvesting greens in salads. Most varieties of lettuce will germinate within five to 10 days of placing the small seeds in soil. Lettuce may also be started indoors in separate containers and planted into the raised bed later. The optimum soil temperature for lettuce growth is between 50 and 60 degrees Fahrenheit. Outdoor temperatures above 80 degrees Fahrenheit may cause some varieties to bolt. The plants will then have premature flowers and small seed heads.
Use the hoe to cultivate the raised growing bed four to six weeks prior to the last frost in spring. The cultivation of the soil will expose hidden weed seeds and small pests to the outdoor elements. Perform cultivation on a weekly basis right up to the planting of the seeds.
Use the garden rake and smooth the soil with the backside of the rake. Do not over-rake the area so the soil is a consistency of fine powder. Leave the soil a little clumpy, as fine powder will tend to from a crust at the surface. This crust will prevent the germinating seeds from breaking above the surface.
Make a small furrow, with the rake handle, down the length of the raised bed. The furrow should be approximately 1/4 to 1/2 inch deep. The rows of furrows should be 18 inches to 24 inches apart.
Pour some of the lettuce seed in your hand. Place the seeds down the furrow at a rate of four to eight seeds per foot of the row. If some extra seeds fall into the furrow, leave them there. You can always thin out plants that crowd each other at a later time.
Cover the seeds with a thin layer of the soil. Water the seeds into the soil with the garden hose and the sprinkler head attachment.
Allow the seeds to germinate and break from the ground. Thin the seedlings after 3 weeks to a final spacing of 6 to 12 inches between each plant. Different varieties will require various plant spacing. Consult the seed provider for specific plant spacing for the species of lettuce grown.