Celery in Zone 8B — Desert Southwest

Growing your own celery here in the Desert Southwest might seem like a challenge, but the crisp, refreshing flavor is worth the effort. Imagine adding freshly harvested celery to your summer salads or using it as a base for hearty winter soups – a taste far superior to anything you'll find at the grocery store. Plus, with the right timing, you can enjoy a rewarding harvest.

Our extreme heat and arid climate definitely present some hurdles for celery, but our long growing season of 279 days gives you a generous window to get it right. By starting indoors and transplanting at the right time, you can work with the weather, not against it, and enjoy a successful celery harvest.

Starting celery indoors is the way to go in our region. Begin in early to late December, giving your seedlings about 10 weeks to get a head start before the weather warms up too much. This early start is crucial considering how very-early our spring season starts.

Use seed trays or small pots filled with a good seed-starting mix. Celery seeds are tiny and need light to germinate, so don't bury them too deeply – just press them gently onto the surface of the soil. Keep the soil consistently moist by bottom watering to avoid disturbing the delicate seeds. Maintain a warm environment, ideally around 70-75°F, and provide plenty of light, either with a grow light or a sunny windowsill.

Transplant your celery seedlings outdoors in late February through late March. Before you plant, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind, preventing transplant shock.

Choose a spot that gets full sun to partial shade (at least 4-6 hours of direct sunlight). Space the seedlings 8-10 inches apart in well-draining soil. Even though our last frost is usually around late February, keep an eye on the forecast and be prepared to cover your young plants if a late cold snap threatens.

Celery is a water hog, plain and simple. In our Desert Southwest climate, consistent watering is absolutely crucial to avoid bitter, hollow stalks. This is the most water-demanding vegetable you can grow, so don't skimp!

During the cooler spring months (late February through May), aim for at least 1-1.5 inches of water per week. Once the extreme heat of summer hits (June through August), increase that to 2-2.5 inches per week, or even more if the soil dries out quickly. The monsoon season can help, but don't rely on it entirely; supplement with irrigation as needed. Use the finger test to check the soil moisture – stick your finger about 2 inches deep, 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 sometimes humid monsoon season. Signs of underwatering include wilting leaves and stunted growth, while overwatering can lead to root rot. A layer of organic mulch, like shredded leaves or straw, can help retain moisture in the soil and keep the roots cool.

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

Alternatively, you can cut the entire plant at the base when the stalks reach 12 inches or more. For a milder flavor, try blanching the stalks by mounding soil around them a week or two before harvest. As our first frost approaches in early December, harvest any remaining celery before it gets damaged by the cold.

Celery can be a bit finicky, and here are three common problems you might encounter in the Desert Southwest:

Bolting from Temperature Stress

• What it looks like: The celery plant prematurely sends up a flower stalk, making the stalks bitter and inedible.
• What causes it: Fluctuations in temperature, especially sudden heat waves in spring, can trigger bolting.
• How to fix/prevent it: Choose heat-tolerant varieties, provide shade during the hottest parts of the day, and ensure consistent watering to reduce stress.

Hollow Stalks

• What it looks like: The celery stalks develop a hollow center, making them less crisp and flavorful.
• What causes it: Inconsistent watering and nutrient deficiencies are the main culprits.
• How to fix/prevent it: Maintain consistent soil moisture, especially during hot weather. Fertilize regularly with a balanced fertilizer.

Stringy Stalks from Heat

• What it looks like: The celery stalks become tough and stringy, making them unpleasant to eat.
• What causes it: Extreme heat and lack of water stress the plant, leading to stringy stalks.
• How to fix/prevent it: Provide shade during the hottest parts of the day, ensure consistent watering, and harvest promptly when the stalks are mature.

Desert Southwest Specific Challenges: Our extreme heat and arid humidity make it extra challenging to keep celery consistently moist and cool. Sunscald can also be a problem, so providing afternoon shade is crucial. Alkaline soil can also affect nutrient availability, so amend your soil with compost and other organic matter to improve its pH and drainage.

Companion planting can help your celery thrive. Green beans are great companions because they fix nitrogen in the soil, enriching it for the celery. Cabbage and other brassicas deter pests that might attack celery. Tomatoes provide shade and support, while onions repel certain insects. Avoid planting celery near carrots, as they compete for the same nutrients in the soil.