Celery

Apium graveolens

The easiest kind is self-blanching celery, whose stalks stay pale without being covered. Plant it in a block, not a row, so the plants shade each other's stems. Celery needs warmth and steady water. Young plants left below 10 °C for long can flower and go to seed, so plant out only once the nights stay mild.

Looking after it

Water: It needs a lot of water. Never let the soil dry out, because dry spells make the stalks stringy and too strong in flavour. In summer, water generously in the morning or evening, with rainwater if you can. Feeding: Celery needs rich soil. Plant it into ground full of compost or manure. On poor soil, scatter a little fertiliser high in nitrogen in summer. In a pot, give a balanced liquid feed every two weeks.

Harvest and keeping

From late summer, dig up whole plants before the leaves turn yellow and before the first frost. Cover them with fleece when the nights turn cold. Use them soon after you dig them up. Wrap it in a damp cloth or a bag and keep it in the fridge. It stays crisp only for a short time, so use it soon.

What can go wrong

Celery leaf miner. Brown, dried-up blotches show on the leaves, where small maggots feed inside. Pinch off those leaves. Cover young plants with fine insect mesh.
Leaf spot. In wet weather, small brown spots with tiny black dots spread over the leaves. Remove the spotted leaves. Don't grow celery or celeriac in the same soil for a few years.
Slugs and snails. Slugs love celery and eat both young plants and stalks. Protect your plants, especially in damp weather.

Growing facts: RHS, UC ANR and seed-company sowing guides. Celery care: RHS. pH: University of Connecticut and University of Maryland extension.