Celery in Zone 9A — Desert Southwest

Celery, with its crisp texture and refreshing taste, is a rewarding challenge for the Desert Southwest gardener. It adds a unique element to your garden and kitchen, offering a satisfying alternative to store-bought options. Plus, homegrown celery has a flavor you just can't find in the grocery store.

Growing celery here requires careful timing, but our long growing season of 298 days makes it entirely possible. While the extreme heat and arid conditions present challenges, starting indoors and strategically managing water will set you up for success. With the right approach, you can enjoy fresh, homegrown celery even in our desert climate.

Starting celery indoors is essential in the Desert Southwest due to our very-early spring character and intense summer heat. Begin in late November through late December, giving the plants ample time to mature before transplanting. You'll want to start your seeds about 10 weeks early.

Use seed trays filled with a well-draining seed-starting mix. Provide consistent warmth, ideally around 70-75°F, and ensure the seeds receive plenty of light – a grow light works wonders. Celery seeds are tiny and need light to germinate, so don't bury them too deep. A light sprinkle of vermiculite is sufficient. Bottom watering is a great trick to keep the soil consistently moist without disturbing the delicate seedlings.

Transplant your celery seedlings outdoors from mid February through mid March, after the last expected frost. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the desert sun and temperature swings.

Choose a location with full sun to partial shade, especially in the afternoon when the sun is most intense. Space the plants 8-10 inches apart to allow for adequate air circulation, which helps prevent disease in our arid climate. Watch out for late cold snaps, and be ready to cover your seedlings if needed.

Celery is extremely thirsty, and consistent moisture is key to its success in the Desert Southwest. This is probably the most important thing to get right. With our extreme heat and arid conditions, celery demands a diligent watering schedule.

During the spring growing season (mid February through late June), aim to water deeply 2-3 times per week, providing at least 1-2 inches of water each time. Use the finger test – if the top 2 inches of soil feel dry, it's time to water. Once the monsoon season arrives (typically mid-July through September), monitor rainfall closely and adjust your watering schedule accordingly. Even with monsoon moisture, supplement with additional watering if the soil dries out.

Water at the base of the plants to avoid wetting the foliage, which can lead to fungal issues, even in our arid environment. Signs of underwatering include wilting leaves and bitter-tasting stalks. Overwatering can lead to root rot, indicated by yellowing leaves and stunted growth. Mulching around the base of the plants with organic matter like straw or wood chips helps retain moisture and regulate soil temperature, offering some protection against the extreme heat.

Your first celery harvest in the Desert Southwest should be from mid May through late June. Celery is typically ready to harvest about 85 days after transplanting. Keep an eye on the stalks as they develop.

You can harvest individual outer stalks when they reach about 8 inches or more, allowing the inner stalks to continue growing. For a larger harvest, cut the entire plant at the base when the stalks are 12 inches or more. Blanched stalks (those that are pale due to being shielded from sunlight) will have a milder flavor. To encourage continued production, harvest regularly, removing outer stalks as needed. As the first frost approaches in early December, harvest any remaining celery to prevent frost damage.

Celery can be tricky in the Desert Southwest, and you might encounter a few common problems:

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 early heat spells in spring, can trigger bolting.
• How to fix/prevent it: Choose bolt-resistant varieties. Provide consistent watering to prevent stress. Use shade cloth during periods of extreme heat to keep the soil and plant cooler.

Hollow Stalks

• What it looks like: The celery stalks develop a hollow center, reducing their crispness and flavor.
• What causes it: Inconsistent watering and nutrient deficiencies, particularly calcium, can lead to hollow stalks.
• How to fix/prevent it: Maintain consistent soil moisture with regular watering. Amend the soil with compost or bone meal before planting to improve nutrient availability.

Stringy Stalks from Heat

• What it looks like: The stalks become tough, fibrous, and stringy, making them less palatable.
• What causes it: Prolonged exposure to high temperatures and dry conditions causes stringiness.
• How to fix/prevent it: Provide afternoon shade with shade cloth during the hottest months. Ensure consistent watering to keep the soil moist. Harvest celery before the heat of summer becomes too intense.

Desert Southwest Specific Challenges: The combination of extreme heat, arid humidity, and intense sunlight in the Desert Southwest makes celery growing especially challenging. Consistent watering is non-negotiable, and providing afternoon shade is often necessary for summer survival. Be vigilant about monitoring your plants and addressing any issues promptly to maximize your chances of success.

Companion planting can definitely help your celery thrive in the Desert Southwest.

Green beans are great companions because they fix nitrogen in the soil, which celery loves. Cabbage repels some common celery pests, and celery reciprocates by deterring cabbage moths. Tomatoes provide shade during the hottest part of the day, protecting celery from sunscald. Onions are also beneficial, as their strong scent deters pests that might otherwise target your celery.

Avoid planting celery near carrots. Carrots and celery compete for the same nutrients in the soil, hindering the growth of both plants.