How to Transplant Leggy Lettuce

Harden off the lettuce seedlings by taking them outside 7 to 10 days before you want to plant them outdoors. Wait until the daily temperatures warm to over 45 degrees Fahrenheit. Put them in a sheltered location away from wind and where they receive filtered or dappled sunshine. Leave them outside for two to three hours. During the hardening-off period, gradually increase the amount of time that the lettuce stays outside, placing it in stronger sunshine over the period. Never let the plants dry out, which can cause wilting and plant death.

Prepare the garden soil for the lettuce plants. Dig up the soil to a depth of 6 to 8 inches and consider amending the soil if you grew lettuce in that area the year before. Lettuce is a leafy crop that requires nitrogen to grow. You can add mulch or top soil to the garden to replenish the nitrogen, as well as adding nitrogen in the form of organic or synthetic fertilizers according to the directions for the product on the packaging.

Water the soil in the garden before you plant the lettuce and let it rest at least a week. Beneficial enzymes and bacteria in the soil need time to grow.

Prune the roots of the lettuce plants a week before transplanting by slipping a knife inside the containers and cutting the plant away from the sides of the pot. If you are growing the lettuce in peat pots, you do not need to complete this step since the peat dissolves when you put the plants in the ground.

Use a hand shovel to dig the holes for the lettuce transplants when they're ready for planting. Dig the hole slightly deeper than the pots and sprinkle some loose soil in the bottom. This loose soil helps the roots penetrate down.

Remove the lettuce plants from their containers if the containers cannot be planted. Gently loosen the roots once the plant is out of the container, spreading them slightly to help the roots grow. Place the transplant in the hole and cover it with dirt, tamping it down slightly. Water the plants.