Celery is a refreshing treat from the garden, and particularly flavourful when fresh. Celeriac is a variety of celery that is grown for its root, which can be used in a variety of dishes. It can be steamed, baked, boiled, pureed, or stir-fried — it's so tasty, even if it is unfamiliar. Both celery and celeriac are slow to germinate and slow growing once they have sprouted, so be patient. Below are some of our top tips on how to grow celery and celeriac from seed.
Season & Zone
Season: Cool season
Start indoors in late winter to mid-spring. Optimal soil temperature: 15-24°C (60-75°F). Seeds take up to 20-30 days for germination.
Sow seeds no more than 5mm (¼”) deep, 3 seeds per pot, and thin to the strongest plant.
Days to Maturity
From transplant date.
Ideal pH: 6.0-6.5. Celery is a heavy feeder and needs rich, moist soil. Add compost to soil and apply ¼-½ cup of complete organic fertilizer per 1.5m (5′) of row. Transplant when seedlings are 10-12cm (4-5″) tall. Avoid transplanting until night time temperatures are reliably at 10°C (50°F) or warmer. Space transplants 30cm (12″) apart in rows at least 45cm (18″) apart. Water frequently. Premature bolting may result from young plants being exposed to temperatures below 13°C (55°F) for several days.
For best flavour and longer storage, water plants the day before harvest. Stalks on the outside of the plant can be harvested at any time. The entire plant may be harvested once the desired size is reached, but the home gardener should leave the plant in the garden and take only what is needed, leaving the root intact. If winter is not too cold, celery will stand in the garden until spring, allowing for light pickings for soups and salads.
In optimal conditions at least 55% of seeds should germinate. Usual seed life: 3 years.
Diseases & Pests
Use floating row covers early in the season, and put up collars if cutworms are present.
Pests: Aphids, Whiteflies, Cutworms, Tarnished plant bug, and Cabbage loopers.
Diseases: Celery mosaic, Leaf blight, Black heart (calcium deficiency: add lime).
Celery is a good partner for beans, the Brassicas, cucumber, garlic, leek, lettuce, onion, and tomatoes.
More on Companion Planting.