By National Gardening Association Editors, June 23, 2008
- Celery requires about 125 days of a long, relatively cool growing season, for a summer harvest, start plants indoors 10 to 12 weeks before the last spring frost date.
- Where the fall climate is mild, try a midsummer seeding in the garden.
- Some gardeners prefer to blanch celery for a milder taste when eaten raw. If you're pressed for time, try a self-blanching variety.
- Enrich the soil by tilling in plenty of organic matter and fertilizer to provide a steady supply of nutrients and moisture.
- Presoak seeds to speed germination, whether you're starting them indoors or sowing directly in the garden.
- Sow seeds indoors in small pots or flats. Move to individual containers when they are 2 inches tall.
- In areas with a long growing season sow seeds in the garden at a depth of 1/8 inch in rows 30 to 36 inches apart after soil temperature reaches 60° F.
- Set out transplants 8 to 10 inches apart in rows 10 inches apart a week or so before your last spring frost date.
- Thin direct-seeded celery plants to stand 8 to 10 inches apart when they're 4 to 5 inches tall.
Apply a heavy layer of mulch immediately after planting and provide a regular supply of water.
- Celery is a heavy feeder, so side-dress with a liquid fertilizer every 2 to 3 weeks.
- Blanch varieties that require it when the plants are 12 inches tall.
- See our article Summer's Bad Guys by Charlie Nardozzi for controls of common celery pests such as earwigs
- Start harvesting outer stalks when they are 6 to 8 inches tall.
Harvest stalks in fall as needed before the ground freezes. Celery can tolerate light frosts.