Celery in Zone 5A — Midwest

Celery, with its crisp texture and refreshing flavor, is a rewarding challenge for the Midwest gardener. Fresh, homegrown celery elevates everything from soups and stews to salads and snacks, and there's a real satisfaction in nurturing this cool-weather crop through our summer heat spells.

Growing celery in the Midwest does present a few hurdles, especially with our variable spring weather and potential for summer heat. However, by starting indoors early and paying close attention to watering, you can definitely enjoy a successful celery harvest within our 157-day growing season.

For Midwest gardeners, starting celery indoors is a must. Begin your seeds indoors from mid-February through early March, about 10 weeks before you plan to transplant. Celery seeds are notoriously slow to germinate, so patience is key.

Use seed trays with a good seed-starting mix, and provide consistent warmth (around 70-75°F) and bright light. A heat mat and grow light can be very helpful. Remember that celery seeds need light to germinate, so don't bury them too deeply; just gently press them into the surface of the soil. Bottom watering is a great way to keep the soil consistently moist without disturbing the delicate seeds.

Given our moderate-to-late springs here in the Midwest, starting this early gives your celery the head start it needs to thrive once the weather finally cooperates.

Transplant your celery seedlings outdoors in early to late May, after the danger of frost has passed. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sunlight, wind, and temperature fluctuations.

Choose a spot with full sun to partial shade and fertile soil. Space the seedlings 8-10 inches apart. Keep in mind that even in May, we can still get some unexpected cool snaps, so be prepared to cover your young plants if a late frost threatens.

Celery is extremely thirsty and needs consistently moist soil to thrive in the Midwest climate. It's the most water-demanding vegetable you can grow, so don't skimp on hydration.

During the warmer months, especially during our summer heat spells, you'll likely need to water your celery deeply every day, providing at least 1-2 inches of water per week. Use the finger test to check the soil moisture: stick your finger about 2 inches deep into the soil, and if it feels dry, it's time to water. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our moderate-to-humid environment.

Signs of underwatering include wilting leaves and hollow stalks, while overwatering can lead to root rot and yellowing leaves. A good layer of mulch, like straw or shredded leaves, will help retain moisture and regulate soil temperature, which is especially helpful during those hot Midwest summers.

In the Midwest, you can expect your first celery harvest from late July through mid-September, about 85 days after transplanting. Look for outer stalks that are at least 8 inches long and thick enough to eat.

You can harvest individual stalks as needed, starting with the outer ones, or you can cut the entire plant at the base when the stalks are 12+ inches tall. Harvesting outer stalks encourages continued production. For a milder flavor, blanch the stalks by mounding soil around them a week or two before harvesting.

As our first frost approaches in early October, harvest any remaining celery before the cold damages it. You can also try covering the plants with a frost blanket to extend the harvest a bit longer.

Here are some common problems you might encounter growing celery in the Midwest:

Bolting from Temperature Stress

• What it looks like: The plant prematurely sends up a flower stalk, making the stalks bitter and inedible.
• What causes it: Fluctuations in temperature, especially a sudden shift from cold to hot. In the Midwest, this can happen during our unpredictable spring weather.
• How to fix/prevent it: Choose bolt-resistant varieties, start seeds indoors early, and protect young plants from temperature swings with row covers. Consistent watering also helps reduce stress on the plants.

Hollow Stalks

• What it looks like: The celery stalks develop a hollow center, making them less appealing and flavorful.
• What causes it: Inconsistent watering, especially during hot weather. Celery needs a constant supply of moisture to develop properly.
• How to fix/prevent it: Water deeply and regularly, especially during our summer heat spells. Mulch around the plants to retain moisture and provide consistent soil moisture.

Stringy Stalks from Heat

• What it looks like: The celery stalks become tough and stringy, making them unpleasant to eat.
• What causes it: Prolonged exposure to high temperatures.
• How to fix/prevent it: Plant in a location that receives partial shade during the hottest part of the day. Consistent watering and mulching can also help keep the soil cool. If a prolonged heat wave is predicted, consider using shade cloth to protect your plants.

Midwest Specific Challenges: The combination of moderate-to-hot heat, moderate-to-humid humidity, and wet-summer rainfall in the Midwest can create a challenging environment for celery. Consistent watering is crucial to prevent hollow stalks and stringiness. Proper spacing and good air circulation can help prevent fungal diseases that thrive in our humid conditions.

Companion planting can be a helpful strategy for growing healthy celery in the Midwest.

Good companions include:

• Green beans: Beans help fix nitrogen in the soil, which benefits celery's growth.
• Cabbage: Cabbage family plants can help deter celery pests.
• Tomatoes: Tomatoes offer some shade to celery, which can be beneficial during our summer heat spells.
• Onions: Onions repel some celery pests and can improve the plant's overall health.

Avoid planting celery near carrots, as they compete for the same nutrients in the soil and can hinder each other's growth.