Celery: Indoor Sow Vegetable
How to Sow
Sowing Seed Indoors:
- Sow celery seeds in the north indoors in a warm, well-lighted area or in a hotbed about 10-12 weeks before they last heavy frost date in spring. In the South, and other mild areas, sow from fall to early spring.
- Sow seeds ¼ inch deep in seed starting formula.
- Firm lightly and keep evenly moist.
- Seedlings emerge in 10-21 days.
- As soon as seedlings emerge, provide plenty of light on a sunny windowsill or grow seedlings 3-4 inches beneath fluorescent plant lights turned on 16 hours per day, off for 8 hours at night. Raise the lights as the plants grow taller. Incandescent bulbs will not work for this process because they will get too hot. Most plants require a dark period to grow, do not leave lights on for 24 hours.
- Seedlings do not need much fertilizer, feed when they are 3-4 weeks old using a starter solution (half strength of a complete indoor houseplant food) according to manufacturer’s directions.
- If you are growing in small cells, you may need to transplant the seedlings to 3 or 4 inch pots when seedlings have at least 3 pairs of leaves before transplanting to the garden so they have enough room to develop strong roots.
- Before planting in the garden, seedling plants need to be “hardened off”. Accustom young plants to outdoor conditions by moving them to a sheltered place outside for a week. Be sure to protect them from wind and hot sun at first. If frost threatens at night, cover or bring containers indoors, then take them out again in the morning. This hardening off process toughens the plant’s cell structure and reduces transplant shock and scalding.
Planting in the Garden:
- Select a location in full sun with a light, rich, moist to wet soil.
- Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones. Work in organic matter prior to planting.
- Space plants 6 inches apart in rows 18 inches apart. Be careful when transplanting as celery develops a tap root that is easily damaged.
How to Grow
- Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their seeds from germinating. Avoid disturbing the soil around the plants when weeding.
- Keep plants well watered during dry periods to promote rapid, uninterrupted growth. Brussels sprouts need 1-1 ½ inches of water weekly. Celery grows best when it has constant moisture, and relatively cool temperatures. It cannot tolerate high heat conditions.
- Tie celery plants together to prevent sprawling and to blanch the interior.
- Monitor for pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.
- Celery can stand a light frost.
Harvest and Preserving Tip
- Harvest celery in about 115 days from setting plants in the garden.
- Harvest stalks by cutting the base at soil level with a knife.
- Celery is great as a fresh snack or diced for use as a seasoning vegetable.
- Celery leaves are also edible. Eat leaves while still tender, before they become fibrous.
- Collect celery seed after flowering and grind up or use for celery flavoring in cooking.
- Wash celery after harvest, pat dry, keep refrigerated.
- Celery may be frozen for later use in cooking, but it does lose its crispness when it is frozen.
- Celery leaves may be dried in a dehydrator.
Common Disease Problems
Bacterial Leaf Spot: This causes brown water soaked spots on the foliage which eventually makes the foliage turn yellow. It thrives in cooler temperatures. Burpee Recommends: Remove infected plants. Rotate crops with plants in a different family. Avoid overhead watering. Do not work around plants when they are wet.
Celery Mosaic Virus: This causes yellowing of foliage, mosaic and or mottling pattern on leaves. Veins become clear, leaves curled and crinkled or otherwise distorted. Burpee Recommends: Rotate crops with plants in a different family. Eliminate weed hosts like wild celery and wild parsnip.
Early Blight: Small yellow spots appear on both sides of the leaves. Later they become gray, circular lesions. Spots dry out and crack and grey fuzzy growth occurs. Burpee Recommends: Do not transplant infected plants.
Fusarium Wilt: This fungal disease causes yellowing and stunting of older plants and yellowing, stunting and death to seedlings. The plant will exhibit signs of wilting frequently and the lower leaves turn yellow and dry up. Burpee Recommends: Plant resistant varieties. Rotate crops.
Pink Rot: The first symptom of pink rot is that brown lesions appear on the petioles. Lesions rapidly expand into soft, watery, areas of decay. Plant tissue can turn pink around the lesions. Profuse white mycelia are present in severe cases. Plant base can collapse. Burpee Recommends: Maintain adequate air movement. Do not water overhead.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps which feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Beet Army Worm: Nondescript brown moths. Young worms feed on celery leaves. Larvae may be found in the petioles. Burpee Recommends: Introduce natural enemies such as parasitic wasps. Remove surrounding weed, as eggs are often found on them.
Cabbage Looper: These worms are green with a white stripe on either side, about 1-1.5 inches long. Burpee Recommends: Hand pick. Floating row covers can help prevent their laying eggs on the plants.
Leafminers: These insects bore just under the leaf surface causing irregular serpentine lines. The larvae are yellow cylindrical maggots and the adults are small black and yellow flies. They do not usually kill plants, but disfigure the foliage. Burpee Recommends: Remove affected foliage.
Root Knot Nematodes: Microscopic worm-like pests that cause swellings (galls) to form on roots. Plants may wilt or appear stunted. This is a serious problem in many Southern states. Burpee Recommends: Do not plant into infested soil. Grow resistant varieties. Try planting ‘Nema-Gone’ marigolds around your plants.
My celery isn’t growing upright and dark green. Why? Probably the plant is not tied together into an upright bundle of stems. This is called blanching. This must be done to turn the inner stems pale and to keep the plants from sprawling.
Can the root be left in the ground and grow again next year? Roots left in the ground will not produce anything harvestable the following year, although the plant is a biennial and may sprout from the roots.
Why does my celery taste bitter? Celery may become bitter from lack of water or high temperatures. Celery prefers cool and constantly moist growing conditions.
Why are my celery stalks tubular? This can occur when the plants experience a lack of water or nutrients. It is still edible but mostly to add to soups and stews.
My celery stems are cracked and striped brown, and the center is blackened, what’s wrong? Your celery may have a boron deficiency. Test your soil, and grow boron deficiency resistant varieties.