Vegetablestem vegetableDemanding

Celery

Apium graveolens

A bog plant grown as a vegetable, and it behaves like one: celery wants more water than almost anything else on a plot and turns stringy and bitter the moment it goes short. Modern self-blanching types removed the earthing-up ritual and did nothing about the watering.

Position: Full sun or Partial shade
Water: high demand
Drainage: Moisture-retentive, Tolerates wet ground
Grows to: 30–45 cm × 25–30 cm
Hardiness: H3
Harvest: August to October
Difficulty: Demanding

Described view

Self-blanching celery growing close together in a block, with the pale inner stems visible where the plants shade one another and the outer stems noticeably greener and coarser

August

Harvest

Celery’s year

Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.

Activity	J	F	M	A	M	J	J	A	S	O	N	D
Sow under cover			March.	April.
Plant out					May.
Harvest								August.	September.	October.

Timing that travels

The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.

Plant out
2–5 weeks after your last spring frost
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Celery — plant out
Checked 2026-08-13

Conditions it needs

Light: Full sun, Partial shade
Frost: Half hardy
Hardiness rating: H3 (RHS)
Grows best at: 15–21 °C
Germinates at: 15–21 °C
Soil: Loam, Clay
Soil pH: 6–7
Drainage: Moisture-retentive, Tolerates wet ground
Water needs: high
Drought: poor tolerance
Waterlogging: good tolerance
Heat: poor tolerance
Wind and exposure: poor tolerance

Where these figures come from

LightSourced guidancemoderate confidence

Royal Horticultural Society: Celery — position

Checked 2026-08-13

FrostSourced guidancehigh confidence

Royal Horticultural Society: Celery — hardiness

Checked 2026-08-13

Hardiness ratingSourced guidancemoderate confidence

Royal Horticultural Society: RHS hardiness ratings

Checked 2026-08-13

Grows best atSourced guidancemoderate confidence

Royal Horticultural Society: Celery — temperature

Checked 2026-08-13

Germinates atSourced guidancemoderate confidence

Royal Horticultural Society: Seed germination temperatures

Checked 2026-08-13

SoilSourced guidancemoderate confidence

Royal Horticultural Society: Celery — soil

Checked 2026-08-13

Soil pHSourced guidancemoderate confidence

Plant Finder — Missouri Botanical Garden: Apium graveolens — culture

Checked 2026-08-13

DrainageSourced guidancemoderate confidence

Royal Horticultural Society: Celery — soil

Checked 2026-08-13

Water needsHorticultural consensusmoderate confidence

Higher than any other common vegetable. Aim never to let it dry out.

No external citation — see the evidence type above.

Checked 2026-08-13

DroughtHorticultural consensusmoderate confidence

The defining weakness. A dry week is enough to make the stems stringy.

No external citation — see the evidence type above.

Checked 2026-08-13

WaterloggingHorticultural consensusmoderate confidence

One of very few vegetables genuinely happy in wet ground.

No external citation — see the evidence type above.

Checked 2026-08-13

HeatHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Wind and exposureHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

On your soil

Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.

Soil	Verdict	Why
Heavy clay	Prefers this soil	Heavy clay suits Celery as it stands: The pH suits it: it wants 6 to 7, and this soil is in that range. It tolerates ground that stays wet, which most crops do not. Clay is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Sandy	Struggles here	Celery is a bog plant grown as a vegetable and needs more water than anything else on a plot. On sand it dries out between waterings whatever the gardener does, and the result — stringy bitter stems — is not visible until harvest, by which point the season is gone.
Chalky and alkaline	Struggles here	Celery struggles on chalky and alkaline: The soil is substantially too alkaline for it: it wants pH 6 to 7, and this soil sits around 7.8 to 8.5. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering. A container or a raised bed of imported soil sidesteps the problem entirely.
Loam	Prefers this soil	Loam suits Celery as it stands: The pH suits it: it wants 6 to 7, and this soil is in that range. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Silty	Grows well here	Celery grows perfectly well on silty without special measures, though it is not the soil it would choose.
Peaty and acid	Grows well here	Celery grows perfectly well on peaty and acid without special measures, though it is not the soil it would choose.
Shallow over rock	Works, with one condition	Celery will crop on shallow over rock, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Made ground and urban soil	Grows well here	Celery grows perfectly well on made ground and urban soil without special measures, though it is not the soil it would choose.

Not sure which you have? Four hand tests will settle it.

Space and spacing

Mature height: 30–45 cm
Mature spread: 25–30 cm
Rooting depth: 30 cm
Spacing: 23–27 cm apart

Where these figures come from

Mature heightHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Mature spreadHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Rooting depthHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
SpacingSourced guidancemoderate confidence: Royal Horticultural Society: Celery — spacing
Checked 2026-08-13

Measured centre to centre. Plants set closer than this compete for light and water long before they look crowded, and the crowding cannot be undone once they are in.

In a container

Minimum volume: 10 litres or more
Minimum depth: 25 cm

Where the container figures come from

Minimum volumeHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Minimum depthHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

Workable only with very reliable watering — a container dries faster than the ground and celery has no tolerance for it.

Where and how you can grow it

Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.

Method	Suitability	What it needs
Open ground	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Traditional dug bed	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Raised bed	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Greenhouse	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Polytunnel	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Hydroponics	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	One of the crops soilless growing genuinely improves: constant water at the roots is exactly what celery wants and what soil struggles to give it.
Container	Marginal source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	Very reliable watering
Windowsill	Marginal source Horticultural consensusmoderate confidence Royal Horticultural Society: Growing herbs and salads indoors Checked 2026-08-13

Growing it

WateringWater heavily and constantly from planting to harvest — more than any other vegetable on the plot. Celery is a bog plant, and a single dry week produces stringy bitter stems that no later watering fixes.
FeedingFeed with a general fertiliser through the season. Celery is hungry as well as thirsty, and pale slow growth is usually nitrogen rather than water.
HarvestingCut the whole head at ground level rather than picking individual sticks, which lets rot into the crown. Self-blanching kinds must be lifted before the first frost; trench celery is hardier and can be left and dug as needed through early winter.
PlantingPlant self-blanching kinds in a block rather than a row, close enough that the plants shade one another's stems — that mutual shading is what blanches them, and a single row of self-blanching celery goes green and stringy. Wait until the risk of frost has passed, because a check from cold makes the plants bolt.
ProtectionCelery is a biennial grown as an annual and is not kept from one year to the next — a plant that survives the winter runs to flower in spring and is useless for eating. What protection does buy is a longer harvest: trench celery is hardy enough to stand into December, and earthing up or a straw mulch round the plants will hold them through moderate frost. Self-blanching kinds are less hardy and should be lifted before the first hard frost.

Where this guidance comes from

WateringSourced guidancehigh confidence: Royal Horticultural Society: Celery — care
Checked 2026-08-13
FeedingSourced guidancehigh confidence: Royal Horticultural Society: Celery — care
Checked 2026-08-13
HarvestingSourced guidancemoderate confidence: Royal Horticultural Society: Celery — harvesting
Checked 2026-08-13
PlantingSourced guidancemoderate confidence: Royal Horticultural Society: Celery — planting
Checked 2026-08-13
ProtectionSourced guidancehigh confidence: Royal Horticultural Society: Celery — cultivation
Checked 2026-08-13

Is it worth putting under cover?

Whether it will grow there is on the methods table above. This is whether the space is well spent, which is a different question and usually the one being asked.

Structure	What protection is worth	What decides it
Greenhouse	Extends the season source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Season length. Celery needs a long run at it and starting under cover is what makes a usable head possible in a British year.
Polytunnel	Extends the season source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Season length.

On a windowsill

Does not work indoors

source

GrowingHQ editorial positionmoderate confidence

How long the crop is actually productive on an ordinary British windowsill without added light.

GrowingHQ editorial synthesis — GrowingHQ

Checked 2026-08-13

Not a windowsill crop. The reason is given — usually light, root volume or sheer size. Water demand and season length. Celery needs constantly wet ground for most of a year to make anything worth eating.

Harvesting

When it is readyCut the whole head from late summer once the stems are a usable thickness. Self-blanching types do not keep in the ground past the first frosts.
How to pick itLift self-blanching celery whole with a fork, cutting the roots off just below the base of the stems. For trench celery, draw the soil away first and cut the head off below soil level. Individual outer stalks can also be pulled from a growing plant if you only want a few, which keeps the rest standing.

Where the harvest guidance comes from

When it is readySourced guidancehigh confidence: Royal Horticultural Society: Celery — harvesting
Checked 2026-08-13
How to pick itSourced guidancehigh confidence: Royal Horticultural Society: Celery — harvesting
Checked 2026-08-13

What goes wrong

Problem	How often	Notes
Celery leaf spot	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	Seed-borne, so nearly all of the useful action is taken before sowing.
Boron deficiency	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	Cracked stem: brown transverse cracks across the ribs while the plant is still growing.
Carrot fly	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13
Slugs and snails	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13
Aphids	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13

Sources for this page

GrowingHQ editorial synthesis · Plant Finder · Royal Horticultural Society

Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-14.