When should I sow celery in the UK?

February to April indoors at 18°C with bottom heat. Don't sow direct; celery seed is tiny and germination is slow and unreliable in outdoor conditions. The long lead time (12–16 weeks from sowing to plant-out) means an early start matters. Don't sow earlier than February or you'll have leggy plants by planting-out time.

What's the difference between self-blanching and trenching celery?

Self-blanching: plant in close blocks (25 cm apart); the plants shade each other, partially blanching the stems naturally; no earthing-up. Crops July–October. Less work; smaller crop; killed by frost. Trenching: plant in a trench 30 cm deep; earth up from August; covered stems blanch white; classic flavour and texture. Crops September–November; more work; stands light frosts.

Why is my celery stringy and bitter?

Drought stress, the dominant cause. Celery needs constant moisture — even brief drying gives stringy stems and bitter flavour. Water deeply twice a week; mulch heavily; never let the bed dry out. Other causes: bolting (from cold check during seedling stage or summer heat), poor soil (celery is a heavy feeder), or simply over-mature plants.

How do I stop celery bolting?

Avoid cold checks at seedling stage — keep plants above 15°C until they have 4–5 true leaves. Choose bolt-resistant cultivars (Galaxy, Loretta). Water deeply through summer; mulch heavily. Once a plant bolts (sends up a tall flower stem), the stems get woody and bitter — pull and use what's still palatable.

Can I grow celery in containers in the UK?

Yes, but it's demanding. Use a deep (40 cm+) container; rich peat-free compost; water daily in summer; feed weekly. Self-blanching types in close groups of 4–6 plants per 40-litre container work. The risk is drying out — container celery needs religious watering.

When do I harvest celery?

Self-blanching types from July–October once the heads are full-sized. Trenching types from September–November once the stems are well-blanched white. Cut the whole head at ground level with a sharp knife; the plant doesn't resprout. Pick before the first hard frost (self-blanching) or before deep frost (trenching).

Aipo

Apium graveolens var. dulce

Sow celery seed indoors from February to April at 18°C; plant out from late May after the last frost. Celery is half-hardy (RHS H3–H4) and demanding — it needs constantly moist, rich soil, full sun for half the day, and protection from slugs. Two main types: self-blanching (Galaxy, Loretta) which need no earthing-up and crop summer to autumn, and trenching (Solid White, Giant Pink) which require deep planting and earthing-up but give classic long white stems for autumn–winter cropping. Bolting in heat above 25°C ruins the crop, so choose bolt-resistant cultivars and water deeply through summer. Pick whole heads when the stems are firm and full-sized; trenching types stand into November with frost protection.

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