Lettuce in Zone 7B — Pacific Northwest

Lettuce thrives in our Pacific Northwest climate better than almost anywhere else. Our mild summers and cool nights create ideal conditions for crisp, sweet leaves without the bitter bite you get from lettuce grown in hotter regions. With our 193-day growing season, you can enjoy fresh salads from early spring through late fall — something that's impossible in most other zones.

While our cool, wet springs can slow down early plantings and slugs love our moist conditions, proper timing makes lettuce one of the most reliable crops you can grow here. The key is working with our climate patterns rather than against them, taking advantage of those cool nights that keep leaves tender even through summer.

Starting lettuce seeds indoors isn't essential in our mild climate, but it gives you a head start on the season when you're eager for fresh greens. Sow seeds in late February through mid-March, about four weeks before you plan to transplant outside. Our slow spring warm-up makes indoor starting particularly valuable for getting lettuce established before the summer heat arrives.

Use seed trays filled with quality potting mix and keep them at around 60-70°F for best germination. Bottom watering works well for lettuce seedlings — fill a tray with water and let the cells soak it up from below. This prevents the tiny seeds from washing away and reduces damping-off issues.

Once seedlings emerge, they need bright light. A sunny south window works, but supplemental grow lights ensure stocky, healthy transplants. Your indoor-started lettuce will be ready to transplant when nighttime temperatures consistently stay above 35°F.

Transplant your lettuce seedlings outdoors from early April through mid-May, once the worst of our spring weather has passed. Even though lettuce handles light frost, those young transplants need a week of gradual hardening off before facing our unpredictable spring conditions. Start with a few hours outside in a protected spot, gradually increasing exposure to wind and temperature swings.

Space plants 6-12 inches apart depending on the variety — leaf lettuce can be closer together while head lettuce needs the full spacing. Our overcast spring days are perfect for transplanting since the seedlings won't face immediate sun stress. Plant them slightly deeper than they were in their containers to encourage strong root development.

Watch the weather forecast after transplanting. If a late cold snap threatens, be ready with row covers or even old sheets to protect your investment. Lettuce starts are inexpensive and widely available at local nurseries if you prefer to skip the indoor seed starting altogether.

Direct sowing lettuce works beautifully in our climate and is often easier than fussing with transplants. Sow seeds from mid-March through late August, taking advantage of our long, mild growing season. The cool soil that challenges warm-season crops is perfect for lettuce germination — seeds will sprout even when soil temperatures are just 40°F.

Prepare a fine seedbed by raking the soil smooth and removing debris. Scatter seeds thinly and cover with just a quarter-inch of soil. Space your plantings 6-12 inches apart, or sow thickly and thin later. The key to continuous harvest is succession planting every 2-3 weeks through summer.

In our dry summer months, keep the seeded area consistently moist until germination. A light mulch of straw helps retain moisture and prevents the soil surface from crusting. Your lettuce will be ready to harvest in about 45 days, giving you fresh salads all season long.

Lettuce has shallow roots and needs consistent moisture to produce tender, crisp leaves. In our Pacific Northwest climate, this means different strategies for different seasons. During our wet spring months, you might not need to water at all, but once our dry summer period begins in July, regular irrigation becomes essential.

Check soil moisture by sticking your finger 2 inches deep near the plants. If it feels dry, it's time to water. During the dry summer months, lettuce typically needs about an inch of water per week. Water at the base of plants rather than overhead — while our dry-summer humidity means disease pressure is lower than in humid climates, wet leaves can still invite problems.

Signs of underwatering include wilting leaves and bitter taste, while overwatering shows up as yellowing lower leaves and sluggish growth. Morning watering works best in our climate since it allows leaves to dry before evening when slugs become active.

A 2-3 inch layer of mulch around plants helps retain moisture and keeps roots cool during our mild summer heat. Straw, shredded leaves, or grass clippings all work well and break down to improve soil over time.

Your first lettuce harvest will be ready from early May through early November, depending on when you planted. Leaf lettuce varieties can be harvested when leaves reach 4-6 inches long, while head lettuce is ready when the heads feel firm and full. Always harvest before the plant bolts — that tall center stalk means the leaves have turned bitter.

For leaf lettuce, cut individual outer leaves with scissors or a knife, leaving the center growing point intact. This "cut and come again" method gives you multiple harvests from each plant. Head lettuce should be cut at the base when mature, though you can sometimes get a second crop of smaller leaves if you leave the roots in place.

In our long, mild fall season, lettuce continues producing well into late October or even November. Cold actually improves the flavor, making fall lettuce some of the sweetest you'll taste. Keep harvesting regularly to encourage continued growth.

As first frost approaches in late October, harvest any remaining heads and store them in the refrigerator. You can also extend the season with row covers, often gaining several extra weeks of fresh lettuce from your garden.

Bolting shows up as a tall flower stalk shooting from the center of your lettuce, making leaves bitter and tough. In our mild Pacific Northwest summers, this is less of a problem than in hotter regions, but long days and any heat stress can trigger it. Plant lettuce in spring and again in late summer for fall harvest. During our warmest weather in July and August, provide afternoon shade and keep soil consistently moist.

Aphids appear as clusters of tiny green, black, or white insects on stems and leaf undersides, leaving sticky honeydew residue and causing curled growth. Our cool nights help keep populations in check compared to hotter climates. Blast them off with a strong spray from the hose, or encourage natural predators like ladybugs. Avoid high-nitrogen fertilizers which make plants more attractive to aphids.

Slugs are our biggest lettuce pest, creating irregular holes and leaving silvery slime trails. Our moist conditions are perfect for these nighttime feeders. Set up beer traps (shallow dishes of beer sunk into soil) or use iron phosphate bait. Water in the morning so soil surfaces dry by evening, and remove hiding spots like boards and dense mulch around plants.

Tip burn causes brown, dried edges on inner leaves due to inconsistent watering affecting calcium uptake. Keep soil evenly moist and avoid fertilizers high in ammonium nitrogen. This problem is less common in our mild climate than in areas with extreme heat, but can still occur during warm spells if watering is inconsistent.

Pacific Northwest gardeners have the advantage of mild summers and naturally lower pest pressure, but our wet springs and slug-friendly conditions require attention to drainage and moisture management around lettuce plants.

Lettuce pairs beautifully with several crops that thrive in our Pacific Northwest conditions. Plant carrots nearby — their deep taproot doesn't compete with lettuce's shallow roots, and the carrot foliage provides light shade during warm weather. Radishes make excellent companions since they mature quickly and help break up soil, plus their peppery flavor deters some pests. Strawberries and lettuce work well together, both preferring consistent moisture and benefiting from mulch.

Chives planted around lettuce beds help repel aphids with their mild onion scent while providing you with fresh herbs for your salads. Avoid planting lettuce near celery or parsley — these plants have similar shallow root systems and high water needs, creating too much competition in our clay-heavy soils. The key is choosing companions that either mature at different times or use different soil layers, maximizing your garden space efficiently.