Romaine Lettuce in Zone 9A — Texas

Romaine lettuce is a winner in Texas because of its crisp texture and mild flavor, making it perfect for salads, wraps, and even grilling. Plus, homegrown always tastes better! With our long growing season, you can enjoy two harvests of this cool-season crop if you time it right.

Sure, we have to contend with the Texas heat and unpredictable weather, but Romaine is surprisingly adaptable if you plan accordingly. Our 293-day growing season gives you plenty of opportunities to get it right, especially with a little shade and consistent watering.

Starting Romaine lettuce indoors in Texas gives you a head start, especially for the early spring crop. Begin your seeds indoors from late December through mid January, about four weeks before you plan to transplant. Use seed trays and a good seed-starting mix.

Keep the trays in a warm spot (around 70°F) with plenty of light – a grow light works wonders. Water from the bottom to prevent damping off; just set the tray in a shallow dish of water until the soil surface is moist. This is especially helpful as our spring can arrive early!

Transplant your Romaine lettuce seedlings outdoors from early February through early March, once they have a few sets of true leaves. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Texas elements.

Space the seedlings 8-10 inches apart in well-drained soil. Keep an eye on the weather; even though it's warming up, we can still get an unexpected freeze. Be ready to cover your plants if a cold snap is forecast.

Direct sowing Romaine lettuce is an easy option in Texas, especially for the fall garden. Sow seeds directly into the garden from mid January through mid September. Just make sure the soil temperature is consistently above 40°F.

Prepare the soil by loosening it and adding compost. Sow seeds about ¼ inch deep and 8-10 inches apart. Keep the soil consistently moist until the seedlings emerge. Direct sowing works best when you can provide consistent moisture, which can be tricky with our unpredictable rainfall.

Watering is key to growing great Romaine lettuce in the Texas heat. Aim to keep the soil consistently moist, but not waterlogged. Romaine needs about 1 inch of water per week, but that can vary depending on rainfall and temperatures.

Stick your finger about 2 inches deep into the soil; if it feels dry, it's time to water. Water at the base of the plants to avoid getting the leaves wet, which can encourage fungal diseases, especially with our variable humidity. In the hottest part of summer, you might need to water daily.

Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. A good layer of mulch, like shredded leaves or straw, helps retain moisture and keep the soil cool, a must for Texas gardens.

You can expect your first harvest of Romaine lettuce from late March through mid December, 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. Don't wait too long, or it will bolt in the heat.

To harvest, simply cut the outer leaves with a knife, leaving the inner leaves to continue growing. This allows for continuous harvesting over several weeks. Alternatively, you can cut the entire head at the base.

As the first frost approaches in early December, harvest any remaining heads to enjoy before the cold weather sets in. You can also try covering the plants to extend the harvest a bit longer, but don't expect them to last through a hard freeze.

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

Bolting in Heat

• What it looks like: A tall flower stalk emerging from the center of the lettuce head. Leaves become bitter and tough.
• 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 months (spring and fall). Choose bolt-resistant varieties. Provide shade with row covers during hot spells. Mulch to keep the soil cool. Harvest leaves as soon as they're ready to beat the bolting.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Warm weather and lush growth. Aphids love tender lettuce leaves.
• How to fix/prevent it: Blast them off with a strong stream of water from the hose. Encourage beneficial insects like ladybugs. Use insecticidal soap or neem oil for severe infestations.

Slugs

• What it looks like: Irregular holes in leaves, especially near the ground. Silvery slime trails on leaves and soil.
• What causes it: Moist conditions and plenty of hiding places. Slugs thrive in damp environments.
• How to fix/prevent it: Set out beer traps (shallow dishes filled with beer). Use iron phosphate bait (safe for pets). Remove mulch and debris where slugs hide. Water in the morning so the soil surface dries out by evening.

Tip Burn

• What it looks like: Brown, dried edges on the inner lettuce leaves.
• What causes it: Inconsistent watering and high temperatures. This prevents the lettuce from taking up calcium properly.
• How to fix/prevent it: Water consistently, especially during hot weather. Ensure your soil has adequate calcium. Choose tip burn-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 watering is crucial to prevent bolting and tip burn. Be prepared to provide shade during the hottest months and monitor for pests like aphids and slugs, which thrive in our warm climate.

Companion planting can help your Romaine lettuce thrive in Texas. Carrots are great companions because they deter lettuce root aphids. Radishes help break up the soil and deter flea beetles.

Strawberries make good ground cover and help retain moisture. Chives and onions repel aphids and other pests. Avoid planting celery or parsley near Romaine lettuce, as they can attract pests that also affect lettuce.