Home Garden

Seed Planting Time for Celery

Celery is a biennial plant that's often grown as an annual. The vegetable has a reputation for being hard to grow and is often considered among the most difficult of all vegetables, says the Cornell Cooperative Extension. Celery seeds are very small and germination is only successful when they're planted at the right time and under optimal growth conditions.
  1. Planting Time

    • Celery is a long season crop, so the slow-germinating seeds are best started indoors where they'll have consistent moisture. Plant seeds in small pots 10 to 12 weeks prior to the last frost in areas with short growing seasons. Vegetables are then ready to harvest in summer. In regions with a long growing season, plant seeds directly in the garden as soon as soil temperature reaches 60 F. For a later harvest, plant seeds during May or June.

    Sowing Method

    • Presoak the seeds to help with germination, whether they're started indoors or outdoors. When you're starting seeds indoors, use a light potting medium and press the seeds lightly onto the soil surface. Keep the medium consistently moist, in an area with temperatures between 70 to 75 F. When plants are about 2 inches tall, move them to separate containers. Transplant them to the garden a week before the last spring frost date. If you're sowing in a garden, plant the seedlings 1/8 inch deep. Space the rows about 3 feet apart. Thin to a distance of 8 to 10 inches when plants are 4 to 5 inches tall.

    Soil

    • Celery grows best in highly fertile soil, and requires plenty of water and fertilizer. Select a moderately drained site and amend with liberal amounts of organic matter--such as peat moss, compost or well-rotted manure--prior to planting. This not only helps to fertilize the soil but also improves the soil's water retention capacity. The addition of organic material makes the element boron--critical for the health of celery--accessible to the plant. The recommended soil pH is anywhere between 6.0 to 7.5.

    Site

    • Plant celery in an area with full sun for best growth. The best location features a high water table or mucky soil, suggests Barbara Damrosch in "The Garden Primer." In its native habitat, the vegetable grows in marshes. Given the right type of soil, celery plants also tolerate partially shaded sites. A large expanse of land isn't necessary for a healthy harvest as 10 bunches of celery easily grow in an 8-foot long row.