Loose-leaf Lettuce

Lettuce is the highest-return crop per square inch in a container garden, and it is the one crop that actually prefers less than full sun. That makes it the answer for balconies that get morning light only. It also bolts in heat, so the honest way to grow it is in spring and again in fall — not in July.

How to grow it

• Sow seed shallowly — lettuce needs light to germinate — and keep the surface moist until seedlings appear.
• Thin to 8 inches apart. Crowded lettuce stays small and bolts early.
• Keep the pot cool: light-colored containers, afternoon shade, and a layer of mulch all delay bolting.
• Feed lightly. Too much nitrogen makes soft leaves that rot in the fridge.
• Sow a small pinch every two weeks rather than one big row, so you are never drowning in lettuce.

What goes wrong

• Bolting: a tall flower stalk and bitter leaves. Once it happens, pull the plant — heat cannot be undone.
• Slugs and snails: overnight holes. Set a beer trap or copper tape around the pot rim.
• Aphids in the folds of new leaves: rinse with a firm water spray every few days.

Harvesting

Cut-and-come-again: harvest outer leaves from 30 days, or cut the whole head 2 inches above the soil and it regrows.

• Harvest in the morning when leaves are crisp and full of water.
• Pick outer leaves first and the plant keeps producing from the center for weeks.
• Wash in cold water and dry in a salad spinner — wet lettuce keeps for days in a plastic bag.

Varieties that work in pots

Salad Bowl · Black-Seeded Simpson · Buttercrunch · Little Gem

Seed is cheap; the pot and the mix are where the money goes. Links to search results on Amazon are affiliate links — see our disclosure.