Celery in Zone 7B — Southeast

There's nothing quite like the crisp snap of freshly harvested celery from your own garden. In the Southeast, with our long summer days and reliable rainfall, celery can thrive, adding a refreshing element to salads, soups, and snacks. Plus, it's incredibly rewarding to grow something that often tastes bland from the grocery store.

While we do face challenges like humidity and potential fungal disease, don't let that deter you. Our long growing season, about 235 days, gives you plenty of time to get celery established and harvested before the first frost. With the right timing and a little extra care, you can enjoy homegrown celery.

Starting celery indoors is the way to go here in the Southeast. You'll want to get those tiny seeds going early to late January, about 10 weeks before you plan to transplant. Celery seeds are notoriously slow to germinate, so starting early gives them a good head start.

Use seed trays and a good seed-starting mix. Celery seeds need light to germinate, so don't bury them too deeply – just gently press them into the surface of the soil. Keep the soil consistently moist, and bottom watering is a great way to achieve this without disturbing the delicate seeds. A warm location and grow lights will help speed things along. Remember, our spring is moderate, so getting them started indoors is key.

Transplant your celery seedlings outdoors mid March through mid April, once the risk 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 and temperatures.

Plant them about 8-10 inches apart in well-drained soil that’s been amended with compost. Even though we often get afternoon thunderstorms in the spring, be sure to keep an eye on the forecast. A late cold snap can still happen, so be prepared to cover your young plants if needed.

Celery is a thirsty plant, and consistent watering is crucial for success in our hot and humid Southeast climate. Aim to keep the soil consistently moist, as even short dry spells can lead to bitter and hollow stalks. This is probably the most water-demanding vegetable you can grow.

During the hotter months, you'll likely need to water deeply several times a week, providing about 1-2 inches of water per week. Use the finger test – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Watering at the base of the plant is preferable to overhead watering, which can encourage fungal diseases in our humid environment.

Keep an eye out for wilting leaves, which indicate underwatering. Yellowing leaves can be a sign of overwatering, so adjust your watering schedule accordingly. A good layer of mulch around your celery plants will help retain moisture and suppress weeds, which is especially helpful during our long, hot summers.

You can expect your first celery harvest mid June through early August, about 85 days after transplanting. The outer stalks will be ready to harvest when they are at least 8 inches long. You can harvest individual stalks as needed, or you can cut the entire plant at the base when the stalks are 12 inches or longer.

To harvest individual stalks, simply use a sharp knife to cut them off near the base of the plant. Be careful not to damage the remaining stalks. Harvesting outer stalks encourages the plant to continue producing new stalks from the center.

As the first frost approaches in early November, harvest any remaining celery. If you're lucky, you might be able to extend the harvest a bit with row covers.

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

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 cool to hot, can trigger bolting. This can happen during our temperature swings in the spring.
• How to fix/prevent it: Choose bolt-resistant varieties and provide consistent watering. If a warm spell is predicted, provide shade during the hottest part of the day.

Hollow stalks

• What it looks like: The center of the celery stalk is hollow instead of solid.
• What causes it: Inconsistent watering and nutrient deficiencies, especially boron deficiency.
• How to fix/prevent it: Maintain consistent soil moisture and fertilize with a balanced fertilizer. A soil test can help determine if you have a boron deficiency.

Stringy stalks from heat

• What it looks like: The celery stalks become tough and stringy.
• What causes it: Prolonged exposure to high temperatures. Our long, hot summers can definitely contribute to this.
• How to fix/prevent it: Provide afternoon shade during the hottest part of the day. Ensure consistent watering and choose heat-tolerant varieties.

Southeast Specific Challenges: Our hot, humid summers and wet-summer rainfall create ideal conditions for fungal diseases. Be sure to provide good air circulation around your plants and avoid overhead watering to minimize disease pressure. Japanese beetles can also be a nuisance, so be prepared to hand-pick them or use insecticidal soap if needed.

Companion planting can be beneficial for celery in the Southeast. Green beans are a good companion because they fix nitrogen in the soil, which celery needs. Cabbage helps to deter some pests that might bother celery. Tomatoes offer some shade, protecting celery from the intense afternoon sun. Onions are also a good choice, as their strong scent can repel certain pests. Avoid planting carrots near celery, as they compete for the same nutrients in the soil.