Pumpkin
Cucurbita maxima
Grown for size and for carving rather than for the kitchen: the big orange varieties are watery and bland, and the ones worth eating are sold as winter squash. It needs more space, more feeding and more water than any other common crop, and one plant will cover several square metres.
- Position
- Full sun
- Water
- high demand
- Drainage
- Moisture-retentive
- Grows to
- 40–60 cm × 200–300 cm
- Hardiness
- H2
- Harvest
- September and October
- Difficulty
- Straightforward
August
Nothing to do
No sowing, planting, harvesting or pruning window falls in August.
Coming next month: harvest.
Pumpkin’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 | April. | May. | ||||||||||
| Plant out | May. | |||||||||||
| Harvest | 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 out1–3 weeks after your last spring frost
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — plant out
Checked 2026-08-13
Conditions it needs
- Light
- Full sun
- Frost
- Frost tender
- Hardiness rating
- H2 (RHS)
- Grows best at
- 18–30 °C
- Germinates at
- 15–35 °C
- Soil
- Loam
- Soil pH
- 6–7
- Drainage
- Moisture-retentive
- Water needs
- high
- Drought
- poor tolerance
- Waterlogging
- poor tolerance
- Heat
- good tolerance
- Wind and exposure
- poor tolerance
Where these figures come from
- LightSourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — position
Checked 2026-08-13
- FrostSourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — 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: Pumpkin — 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: Pumpkin — soil
Checked 2026-08-13
- Soil pHSourced guidancemoderate confidence
- Plant Finder — Missouri Botanical Garden: Cucurbita maxima — culture
Checked 2026-08-13
- DrainageSourced guidancemoderate confidence
- Royal Horticultural Society: Pumpkin — soil
Checked 2026-08-13
- Water needsHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- DroughtHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- WaterloggingHorticultural consensusmoderate confidence
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 | Works, with one condition | Pumpkin will crop on heavy clay, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. For a crop lifted before winter the risk is not rot but the season: waterlogged ground is cold and unworkable in spring, so sowing is late and germination patchy.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse. |
| Sandy | Works, with one condition | Pumpkin will crop on sandy, 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. |
| Chalky and alkaline | Struggles here | Pumpkin 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 Pumpkin 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 | Pumpkin grows perfectly well on silty without special measures, though it is not the soil it would choose. |
| Peaty and acid | Works, with one condition | Pumpkin will crop on peaty and acid, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. For a crop lifted before winter the risk is not rot but the season: waterlogged ground is cold and unworkable in spring, so sowing is late and germination patchy.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse. |
| Shallow over rock | Works, with one condition | Pumpkin 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 | Works, with one condition | Pumpkin will crop on made ground and urban soil, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. For a crop lifted before winter the risk is not rot but the season: waterlogged ground is cold and unworkable in spring, so sowing is late and germination patchy.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse. |
Not sure which you have? Four hand tests will settle it.
Space and spacing
- Mature height
- 40–60 cm
- Mature spread
- 200–300 cm
- Rooting depth
- 45 cm
- Spacing
- 150–200 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: Pumpkin — spacing
Checked 2026-08-13
In a container
Not realistic. The spread alone rules it out.
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 | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Traditional dug bed | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Raised bed | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Greenhouse | MarginalsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Polytunnel | MarginalsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Hydroponics | MarginalsourceGrowingHQ editorial positionmoderate confidence Several square metres of vine for a handful of fruit, plus hand pollination. Everything that makes courgette borderline applies here several times over.
Checked 2026-08-13 | |
| Container | Not suitablesourceSourced guidancemoderate confidence
Checked 2026-08-13 |
Growing it
- FeedingPlant into a pocket of well-rotted manure and feed fortnightly once the fruit sets. Pumpkins are among the hungriest things on a plot and size is almost entirely a function of feeding and watering.
- ProtectionSlide a tile or a piece of wood under each developing fruit. It keeps the skin off wet soil, which is what causes them to rot on the underside just before harvest.
Where this guidance comes from
- FeedingSourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — care
Checked 2026-08-13
- ProtectionSourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — care
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 | No real benefitsourceGrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file.
Checked 2026-08-13 | Sheer size. A pumpkin plant covers several square metres and needs pollinating insects, neither of which a greenhouse offers cheaply. |
| Polytunnel | No real benefitsourceGrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file.
Checked 2026-08-13 | Sheer size. |
Growing it without soil
Nearly anything can be grown in a soilless system by somebody with enough equipment. The useful question is whether it is worth it, in which technique, and what goes wrong.
It can be made to grow, but a soilless system is the wrong tool — usually because of rooting volume, running cost, or a result no better than a pot of compost.
source
GrowingHQ editorial positionmoderate confidence
Several square metres of vine for a handful of fruit, plus hand pollination. Everything that makes courgette borderline applies here several times over.
- GrowingHQ editorial synthesis — GrowingHQ
Checked 2026-08-13
The fruit is mostly water and stores for months in a shed, which is the opposite of a crop worth lit space.
Techniques that suit it
- Drip-fed mediumSolution is dripped into an inert medium around each plant. The most forgiving technique and the one that suits large, long-season, heavy crops.
Horticultural consensusDepends on conditionsmoderate confidence
Applies when: Only in a very large system, and rarely worth it.
No external citation — see the evidence type above.
Checked 2026-08-13
- Root space
- Very large.
- pH band
- 5.5–6.5
Where these figures come from
- Root spaceHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- pH bandSourced guidancehigh confidence
Outside roughly this band, individual nutrients become unavailable even when they are present in the solution — which is why a crop can starve in a full reservoir.
- Purdue Extension — Purdue University: Hydroponic solution management — pH
Checked 2026-08-13
No nutrient recipes here
GrowingHQ records pH bands, which are measurable properties of nutrient availability, and deliberately records no EC or PPM targets and no mixing instructions. Published targets vary by cultivar, growth stage, water source and technique, and the figures that apply to your system are on the product you bought.
Harvesting
- When it is readyThe skin hardens enough to resist a thumbnail and the stalk begins to crack. Cure in the sun for a week or two before storing.
- How to pick itCut the fruit from the vine with secateurs, leaving 5–10 cm of stalk attached like a handle — but never carry it by that handle, because a stalk that pulls out leaves an open wound and the fruit rots from it within weeks. Harvest before the first frost, and cure the fruit in the sun or somewhere warm for ten days to harden the skin before storing.
- Keeping itCured and kept cool and dry, several months.
Where the harvest guidance comes from
- When it is readySourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — harvesting
Checked 2026-08-13
- How to pick itSourced guidancehigh confidence
- Royal Horticultural Society: Pumpkin — harvesting
Checked 2026-08-13
- Keeping itHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
What goes wrong
| Problem | How often | Notes |
|---|---|---|
| Powdery mildew | commonsourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | Almost universal by late summer and rarely costs the crop at that stage. |
| Slugs and snails | commonsourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | Chiefly on young plants; established ones outgrow the damage. |
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.
If something is wrong with it
- White powdery coating on leaves — 2 causes GrowingHQ holds for pumpkin
Something else? Work through it with the diagnostic tool.