Celery Growing Guide
Celery is a classic salad vegetable known for its crunchy, tangy, juicy stems. It is nutritious, rich in nutrients, antioxidants, and fibre, and can be eaten raw, cooked, or added to soups and stews. Cultivated varieties are bred from wild celery (Apium graveolens) which grows in moist, marshy conditions, indicating its preference for consistent moisture.
This guidance applies to the crop in general. Individual varieties and local conditions can differ.
Planting information
Sow seeds indoors between mid-March and early April in seed trays, modules, or small pots of moist peat-free seed compost. Sow thinly on the surface, or with a very light dusting of compost, as seeds need light to germinate. Place in a heated propagator or cover with a plastic bag to maintain at least 15°C for germination. Germination can take up to three weeks. Once seedlings appear, provide plenty of light, water regularly, and keep temperatures above 10°C to prevent bolting. Move seedlings into individual 7.5cm pots when large enough to handle, thinning modular seedlings to one per module. Young plants are ready for outdoor planting around ten weeks after sowing, in late May or early June. Plant young celery outdoors in late May or early June, once all risk of frost has passed and after hardening them off. Ensure temperatures do not fall below 10°C for extended periods. Prepare a sunny site with fertile, moisture-retentive soil. Plant in a block formation, spacing plants about 23cm apart in each direction; this helps self-blanching varieties shade each other. For traditional trench varieties, plant in a single row 30-45cm apart. After planting, cover with cloches or biodegradable fleece to improve growth, keep warm, and prevent bolting. Protect from slugs and snails, and water regularly with rainwater. Alternatively, plant in large containers, spacing plants 23cm apart, using peat-free multi-purpose compost in a sunny, sheltered location.
Harvesting information
Celery is ready to harvest from mid-summer to autumn once it reaches the desired size. Self-blanching and green varieties should be harvested as soon as they are ready, before leaves yellow, as stems become stringy with age. Most are not hardy, so protect with cloches or fleece as night temperatures drop, and harvest before the first frost. Traditional trench celery is ready from late autumn to early winter; protect from harsh frosts. Dig up whole plants as needed and use as soon as possible after harvesting for best crunch, juiciness, and nutrient content.
Storage information
Use harvested celery as soon as possible to maintain crunchiness, juiciness, and nutrient levels.