Container growing lettuce is a common practice for small space gardeners such as apartment dwellers. It can allow an early start because the pots are brought indoors during light freezes and left outdoors during early spring days. Lettuce is a cool-season crop and leaves develop best in cool but not chill temperatures. Growing lettuce in containers also allows you to control weeds and pests more easily than in a large gardening space and affords quick access when you want some leaves for a salad.
Planting Lettuce in Container
Growing lettuce in containers requires the right type of pot and planting medium. Lettuce needs ample room for roots but you can grow several varieties in 6 to 12 inch (15-30.5 cm.) pots. The greens need a consistent supply of moisture as they are almost 95 percent water but cannot tolerate wet roots. A clay pot provides a permeable surface that can evaporate any excess water and prevent soggy roots. Make sure there are adequate drainage holes in whatever container you chose.
The physical attributes for how to grow lettuce in a container are just the media and pots but now we must turn our attention to sowing and management. Planting lettuce in container gardens can be done by direct sowing or transplants. Prior to planting add ½ tablespoon (7 mL.) of time-release fertilizer per gallon (4 L.) of soil. Transplants should be buried ¼ inch (0.5 cm.) deeper than they would be in garden soil and set 6 to 12 inches (15-30.5 cm.) apart. Seeds are sown when soils are not frozen, ½ inch (1.5 cm.) deep and 4 to 12 inches (10-30.5 cm.) apart. Leaf lettuces can be closer together than head types.
How to Grow Lettuce in a Container
Use a professional soil mix for planting lettuce in container situations, as the mix is formulated to hold water and provide nutrients. A soil mix is usually peat or compost, soil, and either vermiculite or perlite for water retention. You’ll need 1 to 3 ½ gallons (2-13 L.) of soil depending on the size of your container. Choose a lettuce mix marked “cut and come again” for repeat harvests. Some recommended varieties for growing lettuce in pots are Black Seeded Thompson and red or green oak leaf types. Loose-leaf lettuces are better suited to pots than head lettuce.
The most important resource when growing lettuce in containers is water. Lettuce has shallow roots and responds best to consistent, shallow watering. Plants grown in the garden need at least an inch (2.5 cm.) per week; lettuce in pots need a bit more.
There are numerous pests that enjoy lettuce as much as you do. Combat them with blasts of water or insecticidal soap; and for slugs, trap them with containers of beer.
Harvesting Container Growing Lettuce
Cut the outside leaves of loose lettuce when the leaves are young. The leaves will grow back and then you can cut away the entire plant. Always cut lettuce when it is tender as they are quick to bolt and become bitter.