Celeriac

1. 1

   Sow indoors with bottom heat

   February to March at 18°C. Surface sow (the tiny seeds need light to germinate); mist regularly to keep the surface moist. Germination 2–3 weeks. Don't sow direct — celeriac needs a long head start.

2. 2

   Prick out into 9 cm pots

   When seedlings have two true leaves, prick out individually. Keep above 15°C minimum; cool checks at this stage cause bolting later.

3. 3

   Prepare rich moist soil

   Full sun, deep fertile soil with plenty of organic matter. Fork in well-rotted manure or compost — celeriac is a hungry crop that grows from a tiny seedling to a fist-sized root over 30+ weeks.

4. 4

   Harden off and plant out

   After the last frost (late May south, early June north). 7–10 days hardening off. Plant 30 cm apart in rows 38 cm apart. Set plants at the same depth they were in the pot; don't bury the crown.

5. 5

   Water deeply and consistently

   Celeriac wants constant moisture from planting through to harvest. Water deeply twice a week in dry weather; mulch heavily with grass clippings or straw. Drought gives small woody roots.

6. 6

   Remove outer leaves and side shoots from July

   As the plant develops, the outer leaves spread out and side shoots emerge from the base. Remove them progressively from July onwards. This redirects energy into swelling the root rather than leaf growth.

7. 7

   Feed and lightly earth up

   Liquid feed monthly. As the root swells above the soil surface, draw a little earth up around it (light earthing-up — not like potatoes or trenching celery). Keeps the developing root tender.

8. 8

   Lift from October

   Lift roots when fist-sized (10–15 cm across). Smaller earlier lifts (golf-ball size) have sweeter flavour; bigger later lifts give more flesh. Use a fork; trim foliage to 5 cm above the crown; brush off soil.

9. 9

   Store or stand in the ground

   Store: layer in damp sand in a frost-free shed; keeps until March. Stand in ground: in milder gardens (southern England, mild south coast), celeriac holds in the ground under a thick straw mulch through winter; lift as needed. Cold-garden growers lift before deep frost.

Celery leaf miner and slugs are the main pests; leaf spot in wet weather.