The wild celery plant - from which cultivated varieties are selected - is found on boggy riversides and marshy ground, giving a clue to the growing conditions it needs. Soil should be moisture-retentive and never dry out. Celery hearts are particularly tasty and can be eaten raw or braised by simmering.
Jobs to do now
- Water regularly - do not allow plants to dry out
- Earth-up if necessary
Month by month
Sow between mid-March and early April in seed trays, modules or pots of moist compost at 15°C (59°F). Sowing seed direct reduces transplant shock, but it is better to start in trays or pots and transfer modules as soon as the seedlings can be handled.
Sow seed thinly and apply the merest of covering of fine vermiculite or sieved compost. Patience is needed as germination takes time. Transplant the young seedlings when large enough to handle, which might not be until several true leaves appear. Plant single seedlings into 7.5cm (3in) pots or modules.
Low temperatures after germination can cause ‘bolting’ (running to seed) later in life; temperatures should not fall below 10°C (50°F) for long than 12 hours until they are established. Delay sowing until suitable temperatures can be maintained.
The key to success with celery is plenty of water throughout the growing season.
It is also liable to bolt or run to flower and seed if shocked or chilled during transplanting or growth. Make sure plants are properly ‘hardened off’ (acclimatised to outdoor conditions) before planting out at the end of May to early June.
Trenching celery: dig a trench 38-50cm (15-20in) wide and 30 cm (12in) deep in October/November or March, incorporating plenty of well rotted organic matter. Add a high potassium general fertiliser, such as Vitax Q4, at a rate of two handfuls per square metre/yard . Plant in line along trench.
Plants can be then earthed up (mounding soil around the stems) so the stems become blanched, start doing this once stems are 30cm tall. Draw up the soil 7.5cm (3in) at a time until the top is exposed. Alternatively, use collars made of corrugated cardboard, brown paper, newspaper, plastic drainpipe or similar.
Other celery, including green and self-blanching celery: Plant 23cm (9in) apart in a block to ensure the plants shade each other to aid blanching.
Water regularly before the onset of dry weather – plants should never be allowed to dry out.
Self-blanching celery can be planted at ground level and will blanch itself by self-shading.
If growing celery in pots, feed every fortnight with a balanced liquid general fertiliser during the summer.
A light dressing of a high nitrogen fertiliser once they are established improves crops.
Celery is ready to harvest once it reaches the desired size, between August and October, and before the first hard frost.
Most types of celery will be damaged by frost, but varieties of trench celery (which are grown in trenches and earthed up) might last into winter, as late as December.
To harvest, cut plants at the base with a sharp knife.
Slugs and snails
These feed on the young seedlings and you'll see the tell tale slime trail on the soil around your crop, as well as on the leaves.
There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers, copper tape and biocontrols.
Celery leaf spot
Brown spots appear first on older leaves, spreading to younger leaves.
Use treated seed and rotate crops.
A hearty roasted celery soup is great for the cold weather. Enjoy with a big chunk of crusty bread.
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.