Romaine Lettuce in Zone 7B — Texas

Romaine lettuce is a fantastic addition to any Texas garden. Its crisp texture and mild flavor make it perfect for salads, wraps, or even grilling. The satisfaction of harvesting fresh lettuce from your own backyard, especially in our climate, is hard to beat.

Growing Romaine in Texas does come with its challenges, namely the extreme heat and unpredictable weather. But with careful timing, you can enjoy a bountiful harvest during our long, 255-day growing season. You can easily get two good harvests in spring and fall.

Starting Romaine lettuce indoors in Texas is an option, particularly for an early spring crop. Begin your seeds indoors from mid January through early February, about four weeks before you plan to transplant. This can give you a jump start before the Texas heat really kicks in.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, bottom watering works great for this. Place the trays in a warm location with plenty of light, either from a sunny window or grow lights. Remember, spring here starts early, so get ahead of the game.

Transplant your Romaine lettuce seedlings outdoors from late February through late March. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Texas elements and reduces transplant shock.

Space your Romaine lettuce plants 8-10 inches apart in well-drained soil. Keep an eye on the weather forecast. A late freeze can happen in March, so be prepared to cover your seedlings if needed.

Direct sowing Romaine lettuce is a viable option in Texas, especially for succession planting. Sow seeds directly into the garden from early February through early September. This gives you flexibility for multiple harvests.

Prepare the soil by loosening it and adding compost. Ensure the soil temperature is consistently above 40°F for good germination. Sow seeds 1/4 inch deep and space them about 8-10 inches apart. Thin seedlings as needed. Direct sowing can be more susceptible to pests, so keep a close watch.

Consistent watering is key to growing crisp, delicious Romaine lettuce in Texas. Our unpredictable rainfall means you can't rely on Mother Nature alone. Aim for consistent moisture, but avoid soggy conditions that can lead to rot.

During the cooler spring and fall months, water deeply once or twice a week, providing about 1 inch of water. In the heat of summer, you might need to water every other day, especially if it's dry. Always check the soil moisture with the "finger test"—if the top 2 inches feel dry, it's time to water.

Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our variable humidity. Signs of underwatering include wilting and dry, brittle leaves. Overwatering can cause yellowing and root rot. A layer of mulch around your Romaine plants can help retain moisture and keep the soil cool during the Texas heat.

You can expect your first Romaine lettuce harvest in Texas from mid April through late November, depending on your planting time. Romaine lettuce is typically ready to harvest about 65 days after planting. Look for outer leaves that are 6-8 inches long, or harvest the whole head when it feels firm and full-sized.

To harvest, you can either cut the outer leaves as needed for a continuous harvest, or cut the entire head at the base. Avoid harvesting after the center stem starts to elongate, as this indicates bolting, which makes the leaves bitter.

As the first frost approaches in mid- November, harvest any remaining heads. Even a light frost can damage the leaves. You can also try covering the plants with a frost blanket for a bit of extra protection.

Here are some common problems you might encounter growing Romaine lettuce in Texas:

Bolting in Heat

• What it looks like: A tall flower stalk emerges from the center of the lettuce head. The leaves become tough and bitter.
• What causes it: Extended warm temperatures. Romaine is a cool-season crop, and the Texas heat can trigger bolting.
• How to fix/prevent it: Time your plantings for cooler parts of the year (spring and fall). Choose bolt-resistant varieties. Provide shade during the hottest part of the day with shade cloth. Mulch to keep the soil cool. Harvest promptly before bolting gets too advanced.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue and curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects. Populations explode in warm weather.
• How to fix/prevent it: Knock them off with a strong spray of water. Encourage beneficial insects like ladybugs. Use insecticidal soap or neem oil for heavy infestations. Avoid over-fertilizing with nitrogen.

Slugs

• What it looks like: Irregular holes in leaves, especially on lower leaves. Silvery slime trails on leaves and soil.
• What causes it: Slugs are nocturnal pests that thrive in moist conditions.
• How to fix/prevent it: Set out beer traps. Use iron phosphate bait. Remove hiding spots like mulch and debris. Water in the morning so the soil surface dries out by evening. Diatomaceous earth around plants can also help.

Tip Burn

• What it looks like: Brown, dried edges on the inner lettuce leaves.
• What causes it: Calcium uptake problems due to inconsistent watering, especially during hot weather.
• How to fix/prevent it: Water consistently to maintain even soil moisture. Avoid fertilizers high in ammonium nitrogen. Ensure good soil calcium levels. Choose resistant varieties. Provide shade during the hottest part of the day.

Texas Specific Challenges: The extreme heat, variable humidity, and unpredictable rainfall in Texas can make growing Romaine lettuce tricky. Consistent monitoring and proactive measures are essential to combat bolting, pests, and diseases. Be ready to adjust your watering schedule based on current conditions.

Companion planting can help your Romaine lettuce thrive in Texas.

Good companions include:

• Carrots: They deter lettuce root aphids.
• Radishes: They act as a trap crop for flea beetles.
• Strawberries: They provide ground cover and suppress weeds.
• Chives and Onions: Their strong scent deters pests like aphids and slugs.

Avoid planting Romaine lettuce near:

• Celery: They compete for nutrients and water.
• Parsley: It attracts aphids.