Swiss Chard in Zone 5B — Great Plains

Swiss chard is a workhorse in the Plains garden. It handles our temperature swings better than spinach, providing a steady supply of nutritious greens from late spring well into fall. Plus, the colorful stems add a touch of beauty to your garden and your plate, a nice reward after a long winter.

Our extreme weather can be a challenge, with intense sunshine, variable rainfall, and the occasional hail. But with a 178-day growing season, you have a wide window to get Swiss chard established and producing. Careful timing and attention to watering will be your keys to success.

Starting Swiss chard indoors gives you a head start, especially if you're further north and have a shorter growing season. It also makes sense if you want earlier harvests. Starting seeds indoors from mid-March through early April gives you about 4 weeks to get seedlings ready for transplanting.

Use seed trays with a good seed-starting mix. Keep them warm (around 70°F) until germination. Once the seedlings emerge, provide plenty of light – a grow light works wonders. Don't forget to water from the bottom to encourage strong root growth and prevent damping-off, a common problem in our variable spring weather.

Transplant your Swiss chard seedlings outdoors from mid-April through mid-May, after the danger of 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 sun and wind.

Space the plants 8-12 inches apart. Keep an eye on the forecast for late frosts or temperature swings that are known to happen this time of year. Be ready to cover your young plants if needed.

Direct sowing is a simple and reliable way to grow Swiss chard in the Plains. Sow seeds directly into the garden from early April through early August. Direct sowing works well if you're not in a rush for an early crop.

Prepare the soil by loosening it and adding compost. Swiss chard seeds germinate best when the soil temperature is between 50°F and 70°F. Plant seeds about ½ inch deep and space them 8-12 inches apart.

Consistent watering is crucial for Swiss chard in our variable Plains climate. While it's more heat-tolerant than spinach, it still needs adequate moisture to thrive, especially during our hot summers. Aim to keep the soil consistently moist, but not waterlogged.

During the spring and fall, when temperatures are cooler and rainfall is more frequent, you might only need to water once or twice a week. In the heat of summer, you'll likely need to water every other day, or even daily during dry spells. Stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our low-to-moderate humidity.

Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around your Swiss chard plants helps retain moisture, suppress weeds, and moderate soil temperature, all important in our extreme climate.

You can start harvesting Swiss chard about 55 days after planting. In the Great Plains, this means you can expect your first harvest from late May through late October, depending on when you planted.

Harvest the outer stalks when they are 8-12 inches long. The colorful stems are perfectly edible and delicious. Cut the stalks at the base of the plant, being careful not to damage the central growing point. This encourages continued production.

Swiss chard is a cut-and-come-again crop, so you can harvest leaves continuously throughout the growing season. As the first frost approaches in mid- October, harvest any remaining large leaves. Smaller leaves will likely not make it through a hard freeze.

Here are some common problems you might encounter with Swiss chard in the Great Plains:

Leaf Miners

• What it looks like: Squiggly, white or yellow tunnels inside the leaves.
• What causes it: Small flies lay eggs on the leaves, and the larvae burrow into the leaf tissue.
• How to fix/prevent it: Cover plants with row covers to prevent flies from laying eggs. Remove and destroy infested leaves. Encourage beneficial insects 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 with tan or gray centers and reddish-brown borders on the leaves.
• What causes it: A fungal disease that thrives in warm, humid conditions.
• How to fix/prevent it: Provide good air circulation. Avoid overhead watering. Remove and destroy infected leaves. Apply a copper-based fungicide if necessary.

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.

Great Plains Specific Challenges: Our hot summers can stress Swiss chard, making it more susceptible to pests and diseases. Consistent watering is essential to keep plants healthy. Wind protection is also important to prevent leaf damage. Monitor plants regularly and take action quickly to address any problems.

Companion planting can benefit Swiss chard in the Great Plains.

Good companions include:

• Lettuce: Provides ground cover, helping to retain moisture and suppress weeds.
• Onion and garlic: Their strong scent deters many pests.
• Green beans: Fix nitrogen in the soil, benefiting the chard.
• Cabbage: Offers similar benefits to lettuce, plus it doesn't compete for the same nutrients.

Avoid planting Swiss chard near:

• Corn: Corn attracts pests that can also affect Swiss chard.
• Potatoes: They compete for the same nutrients in the soil.