Arugula in Zone 7B — Texas

Arugula's peppery bite adds a delicious zing to salads and sandwiches, and it's surprisingly easy to grow here in Texas. Its quick growth makes it a rewarding crop, offering fresh greens in both spring and fall when the Texas heat isn't bearing down quite so hard.

Growing arugula in Texas does come with its challenges, namely the extreme heat that can cause it to bolt. But with a good understanding of planting windows and a little attention to watering, you can enjoy a continuous harvest throughout much of our long 255-day growing season.

Starting arugula indoors is definitely an option, but honestly, it's so quick to germinate and grow that direct sowing is usually the way to go here in Texas. However, if you're itching to get a jump start, especially for that early spring harvest, it can be worth it.

If you decide to start indoors, aim for late January through mid February. Use seed trays or small pots filled with a good seed-starting mix. Keep them warm and provide plenty of light – a simple shop light works wonders. Bottom watering helps prevent damping off, which can be a real problem with seedlings. The early start indoors lets you get a head start on our early spring.

Transplanting arugula seedlings outdoors is best done in late February through early April. Before you move them, harden them off for about a week by gradually exposing them to outdoor conditions. This helps them adjust to the Texas weather.

Space the seedlings about 6 inches apart in well-drained soil. Keep an eye on the forecast – those late freezes can still sneak up on you! A little row cover protection goes a long way if a cold snap is predicted.

Direct sowing arugula is the easiest method, and it works well for most of the growing season here in Texas. You can sow seeds early February through late September for a continuous supply.

Prepare the soil by loosening it and removing any rocks or debris. Sow seeds about ¼ inch deep and 6 inches apart. Keep the soil consistently moist. Arugula is fast-growing, but it also bolts quickly in the heat, so focus your direct sowing efforts on the cooler parts of the year.

Arugula needs consistent moisture to thrive, but it doesn't like to be waterlogged, especially with our variable humidity. The key is to find that sweet spot.

During the spring and fall, when temperatures are milder, aim for about 1 inch of water per week, either from rainfall or irrigation. In the heat of the summer, you might need to increase that to 1.5 inches or more, especially if the humidity is low. Use the finger test – if the top 2 inches of soil feel dry, it's time to water.

Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases, especially when humidity is high. Signs of underwatering include wilting and slow growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch helps retain moisture and keep the soil cool, which is crucial during the Texas heat.

You can start harvesting arugula in late March through late November, about 40 days after planting. The best time to harvest is when the leaves are young and tender, about 2-3 inches long. These will have a milder flavor.

For a more peppery taste, let the leaves grow a bit larger. Harvest by snipping off the outer leaves, leaving the inner ones to continue growing. This encourages continuous production. As the first frost approaches in mid- November, harvest any remaining leaves and consider planting a new batch indoors for winter greens.

Arugula is pretty easy to grow, but here are some common problems you might encounter in Texas:

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in leaves, especially on young seedlings. You'll see small, dark beetles that jump when disturbed.
• What causes it: These small jumping beetles love to feed on arugula leaves. They are most damaging to small, young plants.
• How to fix/prevent it: Row covers are your best friend for protecting seedlings. You can also delay planting until plants are larger and more resilient. Kaolin clay coating can deter them. Neem oil spray also helps. Planting basil or catnip nearby can also help repel them.

Bolting in Heat

• What it looks like: The plant sends up a flower stalk, and the leaves become tough and bitter.
• What causes it: Extended warm temperatures, which are common in Texas, cause arugula to bolt.
• How to fix/prevent it: Time your plantings for the cooler parts of the year (spring and fall). Choose bolt-resistant varieties if possible. Provide shade during warm spells with shade cloth. Mulch helps keep the soil cool. Harvest frequently to encourage leaf production before bolting takes over.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. You might also see sticky honeydew residue and curled or distorted new growth.
• What causes it: Aphids are sap-sucking insects that reproduce rapidly, especially in warm weather.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage beneficial insects like ladybugs and lacewings. Insecticidal soap or neem oil can be used for heavy infestations. Avoid over-fertilizing with nitrogen, as this attracts them.

Downy Mildew

• What it looks like: Yellow patches on leaf tops with fuzzy gray-purple growth on the undersides. Leaves turn brown and die from the bottom up.
• What causes it: This fungal disease thrives in cool, humid conditions.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation by spacing plants properly. Water at the base of the plants, never overhead. Copper-based fungicides can be used for prevention.

Texas Specific Challenges: The hot-to-extreme heat of Texas summers, combined with variable humidity and unpredictable rainfall, can make growing arugula challenging. Bolting is a constant concern, and fungal diseases can spread quickly in humid conditions. Consistent watering and careful monitoring are essential for success.

Arugula plays well with several other plants in the garden. Lettuce and spinach make good companions because they have similar growing requirements and don't compete for resources. Carrots and beets are also beneficial companions, as they help to loosen the soil and improve drainage. Onions can help to repel pests.

Avoid planting arugula near strawberries, as they can attract pests that also affect arugula. Companion planting helps to create a healthy and balanced garden ecosystem, which is especially important in the challenging Texas climate.