Celery in Zone 5B — Midwest

Growing your own celery in the Midwest is surprisingly rewarding. Freshly harvested stalks have a crispness and flavor that store-bought celery just can't match, and it's incredibly versatile in soups, salads, and as a healthy snack. Plus, there's something deeply satisfying about coaxing this cool-weather crop to thrive in our fertile soil.

Celery can be a bit finicky, and our variable spring weather and summer heat spells can present challenges. But with careful timing and attention, you can definitely enjoy homegrown celery. Our 168-day growing season gives you enough time to get it done.

Start your celery seeds indoors in early to late February, about 10 weeks before you plan to transplant them outdoors. Celery seeds are tiny and need light to germinate, so don't bury them too deep. Sprinkle them on the surface of your seed-starting mix and gently mist with water.

Keep the seed trays consistently moist and warm – around 70-75°F is ideal. A heat mat can be helpful. Many Midwest gardeners bottom water their seedlings to avoid disturbing the tiny seeds. Place your seed trays under grow lights, as our spring days can be short and cloudy. Remember, spring in the Midwest often starts moderate-to-late, so you need to get a head start indoors.

Transplant your celery seedlings outdoors in late April through late May, once 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.

When transplanting, space your celery plants 8-10 inches apart in rows. Choose a location that receives full sun to partial shade. Even though our fertile soil is an advantage, add compost to your planting holes to give them a good start. Keep an eye on the weather forecast, as we can sometimes get unexpected cold snaps even in late spring.

Celery is extremely thirsty and needs consistent moisture to thrive in our Midwest climate. Aim to keep the soil consistently wet, as even brief dry spells can cause hollow, bitter stalks. This is probably the most water-demanding vegetable you'll grow.

During the typically wet summers, you might get away with watering deeply 2-3 times a week, providing about 1-2 inches of water each time. Use the "finger test" – stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. During summer heat spells, you might need to water daily. Water at the base of the plants to avoid wetting the foliage, which can increase the risk of fungal diseases in our moderately humid climate.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch, like straw or shredded leaves, can help retain moisture and regulate soil temperature.

You can expect your first celery harvest from mid-July through early September, about 85 days after transplanting. Look for outer stalks that are at least 8 inches long. You can harvest individual stalks as needed, allowing the inner stalks to continue growing.

To harvest, simply cut the outer stalks at the base with a sharp knife. Alternatively, you can harvest the entire plant when the stalks are 12+ inches tall. If you want milder-tasting celery, you can blanch the stalks by mounding soil around them a few weeks before harvest.

As the first frost approaches in early October, harvest any remaining celery. Celery is semi-hardy, so you might get away with a light frost, but it's best to harvest before a hard freeze.

Here are three 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, and the stalks become bitter and tough.
• What causes it: Fluctuations in temperature, especially early in the season, can trigger bolting. This is common with our variable spring weather in the Midwest.
• How to fix/prevent it: Choose bolt-resistant varieties. Start seeds indoors early enough to avoid transplanting during cold spells. Use row covers to protect young plants from temperature swings.

Hollow stalks

• What it looks like: The center of the celery stalk is empty or has large air pockets.
• What causes it: Inconsistent watering or nutrient deficiencies. Celery needs a steady supply of water and nutrients to develop properly, and our summer heat spells can stress them.
• How to fix/prevent it: Water deeply and regularly, especially during dry periods. Amend the soil with compost before planting and fertilize with a balanced fertilizer throughout the growing season.

Stringy stalks from heat

• What it looks like: The celery stalks become tough and fibrous.
• What causes it: High temperatures, especially during the later stages of growth. Prolonged summer heat spells can cause the stalks to become stringy.
• How to fix/prevent it: Choose heat-tolerant varieties. Provide afternoon shade during the hottest part of the day. Ensure consistent watering.

Midwest Specific Challenges: The combination of moderate-to-hot heat, moderate-to-humid humidity, and wet-summer rainfall means you need to be diligent about watering and providing adequate drainage. Watch out for fungal diseases, especially if you overhead water.

Companion planting can help your celery thrive in the Midwest. Green beans are great companions because they fix nitrogen in the soil, which celery loves. Cabbage and other brassicas help deter pests that might attack celery. Tomatoes offer shade during hot summer days, protecting celery from bolting. Onions deter celery pests.

Avoid planting carrots near celery, as they compete for the same nutrients in the soil. In general, avoid planting celery near other members of the Apiaceae family, such as dill and parsley, as they can attract the same pests and diseases.