QUESTION: I don’t have a great space to grow lettuce where it is protected from animals. Can lettuce be grown in pots? -Kev W
ANSWER: Lettuce makes a perfect addition to the container garden, which means you can even grow it on a patio, balcony, or indoors on your windowsill. Lettuce roots are fairly shallow, so the pot doesn’t have to be very deep—you can even use one that has a wide, shallow shape for growing lettuce. Choose one that’s at least six inches deep, and your container must have holes in the bottom for drainage.
If you live in an area where the weather gets really hot, consider how much of the sun’s heat the container will soak up. When a container gets really hot, the soil inside it heats up too, making it unable to retain water for long, and plants can even be burned where they touch the container’s edges. Gardeners in hot regions should look for light-colored containers instead of dark ones, or consider painting them white. Avoid pots made of plastic, metal, and terra cotta. Look for thick or glazed ceramic or concrete containers, or ones made of polystyrene, wood, fabric, clay, pressed paper, coir, or fiber-resin instead. Also keep in mind that small containers will get hot faster than large ones, so they’ll need to be watered more often in summer months.
Use a high quality soil that contains lots of organic material, like compost or peat. You can even add some extra compost or well-rotted manure. You want a loose, loamy soil that drains well so it won’t retain too much water. Consider treating the soil with a balanced granular or water-soluble fertilizer, like a 5-5-5 or 10-10-10 blend, using half the recommended dose, before planting your seeds. You’ll want to fertilize again about every two weeks to keep lettuce growing strong. If you’re not sure which fertilizer to use, read our List of the Best 15 Common Organic Fertilizers.
Sow your seeds densely by sprinkling them on top of the soil and pressing them in gently with your hand. Then water the seeds well to moisten the soil and help keep them in place. As seedlings are growing into young plants, keep the soil consistently moist—never let it dry out, and never let it become waterlogged. Some gardeners like to use a spray bottle to mist seedlings with water while they’re small and delicate. Once they’ve grown to an inch tall, thin the seedlings out, using either your hands or clean, sterilized shears. Spacing after they’re thinned should be four inches apart for leaf lettuce, six to eight inches apart for Romaine lettuces, and 10 to 12 inches apart for head lettuces. Depending on how large your containers are, you may end up with just one lettuce plant per container.
Find a location for your lettuce plants that gets plenty of sun, as lettuce needs at least six hours of direct sun per day. However, if you live in a region where the weather gets hot, some afternoon shade can help prevent plants from getting too stressed or dehydrated and can prevent sunscald as well.
You can harvest your lettuce at the microgreen stage, as baby lettuce once leaves are four inches tall, or wait for it to mature fully. One way to harvest is the cut and come again approach, which allows you to pick exactly as much as you need, leaving the lettuce plant to grow more when you’re through. To harvest this way, use clean, sterilized shears to clip off individual leaves, starting at the outside base of the plant and working your way up and toward the center. You must leave the lettuce plant with at least a third of its foliage intact so it can keep on growing.
If you’d rather, you can harvest the entire head at once, especially if your family eats a lot of lettuce and will use it all up before it spoils. To do this, you can either pull the plant up along with its roots or clip it off at ground level. If you take the whole plant, you can plant new seeds to start the process again and keep lettuce growing continuously in your garden. If you cut it down to the ground, another plant will grow from the roots.