Swiss Chard in Zone 7A — Midwest

Swiss chard is a fantastic addition to any Midwest garden. The mild-to-warm summer nights and fertile soil of Zone 7A provide ideal conditions for growing this nutritious green. You'll appreciate its slightly earthy flavor in salads, soups, and stir-fries, and the colorful stems add a vibrant touch to your plate.

While Midwest weather can be unpredictable with cold winters and variable springs, don't let that deter you. Our 193-day growing season gives you plenty of time to enjoy a bountiful harvest of Swiss chard. With proper timing, you can easily navigate the challenges and reap the rewards of growing this hardy vegetable.

Starting Swiss chard indoors in the Midwest is optional, but it can give you a head start, especially if we have a late spring. If you choose to start indoors, aim for early to late March, about four weeks before you plan to transplant.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, and consider bottom watering to prevent damping off. Place the trays in a warm location with plenty of light, such as under grow lights or near a sunny window.

Transplanting Swiss chard seedlings outdoors in the Midwest can be done from early April through early May, after the danger of hard frost has passed. However, watch for late frost and protect your plants if necessary.

Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. Choose a location with full sun to partial shade and space the plants 8-12 inches apart. Our fertile soil usually doesn't need much amending, but adding some compost never hurts.

Direct sowing Swiss chard is a straightforward method that works well in our Midwest climate. You can direct sow from late March through mid August.

Prepare the soil by loosening it and removing any rocks or debris. Sow seeds about ½ inch deep and 8-12 inches apart. Keep the soil consistently moist until the seeds germinate. Direct sowing is a great option, but remember that you'll need to thin seedlings as they grow.

Swiss chard thrives with moderate, consistent watering, which is especially important during our moderate-to-hot summer heat spells. Aim to keep the soil evenly moist but not waterlogged.

During the spring and fall, when temperatures are cooler and rainfall is more frequent, you may only need to water once or twice a week. In the heat of summer, increase watering to two or three times per week, providing about 1 inch of water each time. 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 increase the risk of fungal diseases in our moderate-to-humid climate. Overwatering can lead to root rot, while underwatering can cause the leaves to wilt and become tough.

Mulching around your Swiss chard plants with straw or wood chips helps retain moisture and suppress weeds. This is particularly helpful during summer heat spells.

You can expect your first harvest of Swiss chard in late May through late October, about 55 days after planting. Harvest the outer stalks when they reach 8-12 inches in length.

The colorful stems (red, yellow, white) are just as edible as the leaves. Cut the stalks at the base of the plant, leaving the inner leaves to continue growing. This cut-and-come-again method allows for continuous harvest throughout the growing season.

As the first frost approaches in mid- October, you can extend your harvest by covering the plants with a cold frame or row cover. This will protect them from the cold and allow you to enjoy fresh Swiss chard for a few more weeks.

Swiss chard, like any vegetable, can be susceptible to problems in the garden. Here are some common issues we see in the Midwest:

Leaf Miners

• What it looks like: Squiggly, white or tan tunnels within the leaves.
• What causes it: Small flies lay eggs on the leaves, and the larvae burrow inside to feed. They thrive in our moderate-to-humid summers.
• How to fix/prevent it: Remove and destroy affected leaves. Cover plants with row covers to prevent flies from laying eggs. Encourage natural predators like parasitic wasps.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects. Populations explode in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer (it attracts them).

Cercospora Leaf Spot

• What it looks like: Small, circular spots on the leaves that start as tan or gray and eventually turn brown. The spots may have a reddish-purple border.
• What causes it: A fungal disease that thrives in warm, humid conditions, which we often experience in the Midwest.
• How to fix/prevent it: Remove and destroy affected leaves. Improve air circulation by spacing plants properly. Avoid overhead watering. Apply a copper-based fungicide as a preventative measure.

Slugs

• What it looks like: Irregular holes in leaves, especially low-growing plants. Silvery slime trails on leaves and soil. Damage worse at night and in wet weather.
• What causes it: Gastropods that feed at night in moist conditions. Hide under mulch, boards, and debris during the day.
• How to fix/prevent it: Beer traps (shallow dish of beer sunk into soil). Iron phosphate bait (pet-safe). Remove hiding spots. Water in morning so soil surface dries by evening. Copper tape around beds. Diatomaceous earth around plants.

Midwest Specific Challenges: The moderate-to-hot heat, moderate-to-humid humidity, and wet-summer rainfall in the Midwest can create ideal conditions for fungal diseases and pests like leaf miners and slugs. Regular monitoring and preventative measures are key to keeping your Swiss chard healthy.

Companion planting can help your Swiss chard thrive in the Midwest garden.

Good companions include lettuce, which provides ground cover and helps retain moisture. Onions and garlic deter pests with their strong scent. Green beans fix nitrogen in the soil, benefiting Swiss chard's growth. Cabbage family plants like broccoli and kale share similar nutrient needs and can grow well together.

Avoid planting Swiss chard near corn and potatoes. Corn can shade the Swiss chard, reducing its sunlight exposure, and potatoes compete for the same nutrients in the soil.