Why does my lettuce taste bitter?

Bitter lettuce is almost always a sign that the plant is 'bolting,' or starting to produce a flower stalk. This is a natural response to stress, usually caused by hot weather. Once a lettuce plant begins to bolt, the flavor becomes bitter and the leaves tough. Harvest your lettuce before the weather gets too hot, and choose bolt-resistant varieties for spring planting.

How do you harvest leaf lettuce so it keeps growing?

This is called the 'cut-and-come-again' method. Instead of pulling the whole plant, use scissors to snip the outer leaves about an inch above the crown (the base of the plant). The inner leaves will be left to continue growing, allowing you to get several harvests from a single plant.

How to Grow Lettuce: A Cool-Weather Crop Guide

There's nothing quite like the taste of freshly picked lettuce. As a cool-weather crop, it's one of the first things you can plant in the spring and one of the last you can harvest in the fall, providing a long season of delicious salads.

Planting & Spacing

When to Plant

Lettuce thrives in cool weather. Direct sow seeds in the garden as soon as the soil can be worked in the spring. For a fall crop, plant seeds about 8 weeks before the first expected frost.

Pro Tip for Desert Gardeners (Mesa, AZ): September is the perfect time to start! Sow lettuce seeds directly in the garden now (early September) for a harvest that will last all fall and winter. Provide some afternoon shade until the weather cools down.

Sun and Soil

Lettuce prefers full sun in cool weather, but appreciates afternoon shade in warmer regions. It grows best in loose, well-draining soil rich in organic matter. Work compost into the top few inches of soil before planting.

Succession Planting

For a continuous supply of lettuce, practice succession planting. Sow a new small batch of seeds every 2-3 weeks. This prevents you from having too much lettuce all at once.

Spacing

Leaf Lettuce: Sow seeds thinly in rows, or broadcast over a bed. Thin to 4-6 inches apart.
Romaine/Head Lettuce: Space seedlings or thin to 8-12 inches apart to give heads room to form.

Watering & Care

Watering

Lettuce has shallow roots and requires consistent moisture. Keep the soil evenly moist but not waterlogged. Inconsistent watering can lead to bitter flavor.

Fertilizing

If you start with rich, compost-amended soil, you may not need to fertilize. If growth seems slow, you can give your plants a boost with a liquid fertilizer high in nitrogen (the first number on the label), which promotes leafy growth.

Common Pests & Problems

Bolting

When temperatures rise, lettuce will send up a flower stalk in an attempt to reproduce. This is called bolting, and it makes the leaves bitter. To prevent it, choose heat-tolerant varieties, provide afternoon shade, and keep the soil consistently moist.

Aphids & Slugs

Aphids can be washed off with a spray of water. Slugs are best controlled by hand-picking in the evening or using traps like a shallow dish of beer.

Harvesting

Harvesting methods depend on the type:

Leaf Lettuce: Use the "cut-and-come-again" method. Snip the outer leaves, leaving the center to grow for future harvests.
Head Lettuce: Harvest the entire head once it's firm and full. Cut the plant at the soil level.

Harvest lettuce in the morning when the leaves are crisp and full of moisture.