How to grow Celery

Where to plant

Celery needs rich, moist soil high in organic matter, ideally a fertile sandy loam, in full sun or with light afternoon shade where it is warm. Its roots are small and shallow and it is a poor nutrient forager, so it depends on a well fed, well watered bed. Utah State gives its ideal range as 55 to 65°F, with several weeks below about 55°F making young plants flower, and heat above 85°F making stalks fibrous.

In Florida, the Gulf South, Texas, the desert and Southern California, set transplants out in fall and winter for a cool season harvest. In the Mid-South, plant in April or in August for fall. Across the North, the Midwest, the Mountain West, the Pacific Northwest and Alaska, start seed indoors 10 to 12 weeks ahead and plant out once after the last frost, protecting young plants from cold nights.

Choosing a variety

Utah types such as Tall Utah and Pascal types stay green and are considered the finest quality. Tango is quicker, with tender, smooth stalks. Leaf or cutting celery is the easiest choice for a beginner or a pot.

How to plant

1. Soak the seed in water for a day or two, changing the water daily, to leach out natural germination inhibitors.
2. Sow on the surface of moist seed starting mix, barely covered, indoors 10 to 12 weeks before planting out. Keep it at 60 to 70°F and moist; seedlings take 2 to 3 weeks.
3. Grow seedlings on in bright light and pot them up. Transplants are ready with 3 to 4 true leaves and a good root system.
4. Harden off and plant at the same depth they grew, about 8 to 12 inches (20 to 30 cm) apart in rows 2 feet (60 cm) apart. Close spacing encourages taller stalks.
5. Protect young plants with row covers or cloches on cold nights, as weeks of cold make them bolt.

Watering and feeding

Water deeply and often, at least 1 to 2 inches a week, soaking the soil each time; drip irrigation works well. Any water stress makes the stalks stringy and strong tasting, and regular watering right up to harvest gives the crispest celery. Mulch with compost to hold moisture.

Work a complete fertilizer high in potassium and plenty of compost into the bed before planting, guided by a soil test. Side dress with nitrogen about 4 and 8 weeks after transplanting.

Pruning and care through the year

• Weed often and shallowly; celery competes poorly and its roots are near the surface.
• Blackheart, where the center leaves turn black and die, comes from a local calcium shortage made worse by water stress. Steady watering is the best prevention.
• To blanch for paler, milder stalks, wrap the stalks with cardboard or paper for the last two to three weeks, or grow self blanching varieties. Many gardeners skip this, as green celery has more flavor.

Harvesting

Start cutting outer stalks once they are about 8 to 12 inches (20 to 30 cm) long, working from the outside in so the plant keeps growing, or cut the whole plant at the base once it is about 3 inches (8 cm) across. The inner stalks are the most tender.

Celery picked in hot, dry weather can be tough and bitter. Refrigerated, it keeps for up to 2 weeks. The leaves are good in soups and stocks.

Growing in pots

Celery, especially leaf celery, can grow in a pot at least 12 inches (30 cm) wide and deep with a rich, moisture holding mix. Pots dry quickly, so water daily in warm weather.