Germination temperature
About 15-24 °C (59-75 °F); a warm day and cooler night suits it.
Vegetable growing guide
Celery seed is tiny, needs light to germinate and can take up to three weeks to sprout. Young plants must also be kept out of the cold, or they bolt instead of forming thick stalks.
About 15-24 °C (59-75 °F); a warm day and cooler night suits it.
On the surface, or under a bare dusting of sieved compost.
About 1-3 weeks; roughly 7 days at 20 °C (68 °F), longer in cool conditions.
Needs light to germinate; do not bury the seed.
None required; steady moisture and warmth matter more.
Transplant. Seedlings need about 10-12 weeks indoors before planting out.
Celery seed is extremely small, more than 2,000 seeds per gram. Sow it thinly from a folded paper or mix it with fine dry sand so it does not land in clumps.
Not needed. The seed coat does not block water uptake.
Not needed. Cold treatment does not help germination, and cold is harmful to seedlings later because it triggers bolting.
Not required. Germination is slow and irregular by nature; constant surface moisture, light and warmth are what speed it up.
Keep the tray at 15 °C (59 °F) or warmer; 20-24 °C (68-75 °F) is typical guidance. Data compiled by the University of California show about 7 days to emergence at 20 °C (68 °F), 12 days at 15 °C (59 °F), 16 days at 10 °C (50 °F) and little or no germination at a constant 25 °C (77 °F) or above. The same handbook lists alternating 29 °C day and 21 °C night (85/70 °F) with diffuse light and high moisture as optimal, so avoid steady heat rather than warm days.
Sow on the surface of moist compost and press lightly. If anything, add only a very fine dusting of sieved compost or vermiculite.
A fine, moist, peat-free seed compost in trays or modules. Celery later prefers fertile, moisture-retentive soil with pH about 6.0-7.5.
The surface must never dry out while seed is germinating. Cover the tray with a clear lid or bag and mist rather than pour water.
Celery needs light to germinate, so keep the tray in bright, indirect light, not in darkness or direct hot sun.
Allow 1-3 weeks. Emergence is uneven, so do not discard a tray too early.
When seedlings are big enough to handle, move them to 7.5 cm (3 in) pots or keep one per module. Keep them above 10 °C (50 °F) at all times.
Plant out about 10-12 weeks after sowing, after hardening off, once air temperatures stay above 10 °C (50 °F). Space plants about 23 cm (9 in) apart each way in a block, or 30-45 cm (12-18 in) apart in rows.
Celery grows best at mean temperatures of 16-21 °C (60-70 °F). Water often: it is shallow-rooted and becomes tough and stringy when short of water or nitrogen.
Cause: young plants exposed to cold. Temperatures below about 4-13 °C (40-55 °F) induce bolting, and plants left below 10 °C (50 °F) for more than about 12 hours are at risk. Fix: keep seedlings warm, do not plant out early, and protect new plants with fleece or a cloche during cold nights.
Cause: seed buried too deep, surface allowed to dry, or a constant temperature of 25 °C (77 °F) or more. Fix: resow on the surface in bright indirect light, keep evenly moist, and let nights cool slightly.
Cause: dry spells, low nitrogen, or heat; average highs above 24 °C (75 °F) in the last month before harvest reduce quality. Fix: water consistently, side-dress nitrogen, and time the crop for the cooler season.
Cause: a calcium-related disorder of the young heart leaves. Fix: keep soil fertile and evenly moist; where it persists, commercial growers apply calcium nitrate or calcium chloride as a spray directed at the plants.
Cause: celery leaf miner larvae or celery leaf spot. Fix: remove affected leaves and avoid growing celery in the same soil within a few years.
Celery takes about 100-135 days from transplanting to harvest and grows best between 16 and 21 °C (60-70 °F). In India, plains growers should time sowing so the crop grows through the cool months without frost; hill areas can grow it in summer.
Mulch at least 5 cm (2 in) deep, leaving a gap around the stems, and water early in the morning or in the evening.
Celery is a heavy nitrogen feeder. A balanced liquid feed every two weeks suits container plants.
Tall Utah is a green celery normally eaten unblanched. If you want paler, milder stalks, wrap them with cardboard or paper a few weeks before harvest, leaving the top third of the leaves exposed.
Start Tall Utah celery seeds indoors for crisp green stalks in the cool season.
Celery is naturally slow: allow up to three weeks. Keep the seed on the surface in bright indirect light, constantly moist, and at 15-24 °C (59-75 °F). Cool conditions slow it down further.
Young celery plants that are chilled, roughly below 10 °C (50 °F) for long periods, start to bolt. Keep seedlings warm and do not plant out until nights stay mild.
It is possible but difficult, because the tiny seed must stay on a constantly moist surface for up to three weeks. Starting in trays and transplanting gives much more even results.