Arugula in Zone 7A — Northeast

Arugula is a fantastic addition to any Northeast garden. Its peppery bite adds a delicious kick to salads, pizzas, and more. Plus, arugula is a quick grower, giving you a continuous harvest throughout our relatively short growing season. The cool nights we often experience here enhance the flavor, making it even more enjoyable.

We all know the challenges of gardening in the Northeast: late spring frosts and early fall freezes can make things tricky. But with careful timing and a little planning, you can easily grow a bumper crop of arugula during our 198-day growing season. It's all about making the most of the summer!

Starting arugula indoors is definitely an option, especially if you're eager to get a jump on the season. Starting in late February through mid March gives you a head start. However, arugula grows so quickly that direct sowing often works just as well.

If you decide to start indoors, use seed trays or small pots filled with a good seed-starting mix. Keep them in a warm spot (around 70°F) and provide plenty of light – a grow light works wonders, especially with our often-cloudy spring weather. Don't forget to water from the bottom to avoid damping off!

Transplanting arugula seedlings outdoors should happen in late March through early May, once the risk of a hard frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the cooler temperatures and stronger sunlight.

Space your arugula plants about 6 inches apart in a well-prepared bed. Keep an eye on the forecast, as we can sometimes get unexpected cold snaps even in late spring. Be ready to cover your seedlings if frost threatens.

Direct sowing is the most common and easiest way to grow arugula in the Northeast. You can sow seeds directly into the garden mid March through early September. Arugula germinates quickly, especially in cool soil.

Prepare your soil by loosening it and adding some compost. Sprinkle the seeds thinly over the surface and gently rake them in. Keep the soil consistently moist until the seedlings emerge. Remember, arugula bolts in hot weather, so focus on spring and fall plantings for the best results. Thin seedlings to about 6 inches apart once they're a few inches tall.

Arugula needs consistent moisture to thrive, but overwatering can lead to problems. In the Northeast's climate, with our moderate heat and moderate-to-humid summers, finding the right balance is key. Aim for consistently moist soil.

During the spring and fall, when temperatures are cooler, you might only need to water once or twice a week, depending on rainfall. In the heat of summer, especially if we have a dry spell, you may need to water more frequently. Stick your finger about 2 inches deep into the soil – if it feels dry, it's time to water.

Generally, aim for about 1 inch of water per week. Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our humid climate. Yellowing leaves can indicate overwatering, while wilting leaves signal underwatering. A layer of mulch, like straw or shredded leaves, can help retain moisture and keep the soil cool.

You can expect your first arugula harvest in late April through early November, about 40 days after planting. The best time to harvest is when the leaves are 2-3 inches long for a milder flavor. Larger leaves will have a more pronounced peppery taste.

Harvest by snipping off the outer leaves with scissors or your fingers, leaving the inner leaves to continue growing. This encourages continuous production throughout the season. Avoid harvesting when the plants are stressed from heat or drought, as this can affect the flavor.

As the first frost approaches in late October, you can extend your harvest by covering the plants with a cold frame or row cover. This will protect them from the frost and allow you to enjoy fresh arugula for a bit longer.

Here are some common problems you might encounter growing arugula in the Northeast:

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in leaves, especially on young seedlings. You might see small dark beetles that jump when disturbed.
• What causes it: These small jumping beetles feed on the leaves. They are most damaging to small, young plants.
• How to fix/prevent it: Use row covers to protect seedlings during their vulnerable stage. You can also delay planting until the plants are larger and more resilient. Coating plants with kaolin clay can deter them. Neem oil spray can also help. Interplanting with basil or catnip is reported to help. Healthy, vigorous plants tend to outgrow the damage.

Bolting in Heat

• What it looks like: The plant sends up a flower stalk, and the leaves become tough and bitter. Harvest quality declines.
• What causes it: Extended warm temperatures above arugula's comfort zone.
• How to fix/prevent it: Time your plantings for cool weather in spring and fall. Choose bolt-resistant varieties if you can find them. Provide shade during warm spells with shade cloth. Mulch to keep the soil cool. Harvest leaves frequently before bolting progresses.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. You might see sticky honeydew residue or curled and distorted new growth.
• What causes it: These sap-sucking insects reproduce rapidly. Ant colonies may farm them for honeydew.
• How to fix/prevent it: Knock them off with a strong spray of water. Encourage ladybugs and lacewings, which are natural predators. Use insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer, which attracts them.

Downy Mildew

• What it looks like: Yellow patches on leaf tops with fuzzy gray-purple growth on undersides. Leaves brown and die from the bottom up.
• What causes it: This oomycete pathogen spreads in cool, humid conditions via wind-carried spores.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation around plants. Water at the base, never overhead. Copper-based fungicides can be used for prevention. Plant resistant varieties if available.

Northeast Specific Challenges: Our region's moderate heat and moderate-to-humid humidity mean that bolting and downy mildew can be significant concerns, especially during the summer months. Regular monitoring and preventative measures are key to keeping your arugula healthy and productive. The even rainfall helps with consistent watering, but also creates conditions for fungal diseases.

Arugula benefits from companion planting. Lettuce and spinach are good companions because they share similar growing requirements and don't compete for resources. Carrots and beets are also helpful companions, as they loosen the soil and improve drainage. Onions deter pests like aphids, protecting your arugula. Avoid planting arugula near strawberries, as they can attract pests that also affect arugula.