Lettuce is an easy crop to grow indoors. This cool-weather crop cannot tolerate warm temperatures, making it ideal for the indoors during the summer. Lettuce also needs limited space to grow, making it ideal for people with no outdoor gardening space. You can also grow lettuce indoors during the winter, allowing for fresh crops to enjoy while the ground is too cold to grow anything.
Fill pots with 2 inches of potting soil. Poke a few holes in the bottom of the pots to help with drainage. Choose pots that are at least 6 to 8 inches deep. Use a 12-inch-deep or 1-gallon pot if you are growing two lettuces. Any type of pot from ceramic to gallon cans will serve; you can also use a window box.
Add 1 part vermiculite, 1 part peat and 1 part perlite to the soil. Mix it by hand.
Plant the lettuce seeds about 1/8-inch deep in the pots.
Keep pots in a place where the temperature is 4.44 to 18.3 degrees Celsius. Wait one to two weeks for the seeds to germinate.
Thin out the lettuce seedlings to one seedling per 6 inches. Put the pots in a place where the seedlings get six to eight hours of sunlight per day. Water so the soil is constantly moist, but not soaked.
Feed lettuce every two weeks with a 15-15-15 fertiliser. Follow instructions on the fertiliser package for best results.
Harvest the lettuce when the leaves are big enough to pick.