How to Grow Zucchini (Courgettes)
On this page
- Zucchini (Cucurbita pepo)
- Quick Facts
- At a Glance
- Do You Need Two Plants? (And Does Tomato Feed Help?)
- Growth Stages
- Soil & Growing Conditions
- Harvest & Storage
- Diseases
- Pests
- Pollination
- Plan your Zucchini (Courgettes) planting
- Growing Zucchini in another region
- Sources
- Nutrient Issues
- Frequently Asked Questions
Courgettes — called zucchini in the US and Canada — are frost-tender at every stage of growth and need soil around 18°C to germinate reliably. Once fruiting starts, check plants every couple of days and pick the fruit small, at 10–12.5cm (4–5in) long: left on the vine it quickly swells into an oversized marrow and further cropping slows, whereas regular picking can keep a single healthy plant producing three or four fruits a week.
The short answer
- Ready in
- 55 days after planting out
- Site
- 6+ hours of sun, soil pH 6–6.5
- Biggest risk
- Grey mould
Core growing advice on this page is checked against named horticultural sources — see References.
Zucchini (Cucurbita pepo)
Also known as: Zucchini · 18 sources cited · Verified
Quick Facts
At a Glance
Do You Need Two Plants? (And Does Tomato Feed Help?)
Do you need two plants to get fruit? No -- one is enough. Courgettes are monoecious, carrying separate male and female flowers on the same plant (Iowa State University Extension confirms this directly: "they produce separate male and female flowers on the same plant"). What you do need is pollinating insects to move pollen between those flowers, since the plant can't do it alone -- in cool, dull early-summer weather when bees are less active, fruit can fail to set or rot off while small. If that happens, hand-pollinate: transfer pollen from a freshly opened male flower onto a female flower with a soft brush, or press the two together.
Does tomato feed help? Yes, genuinely -- tomato feed is a high-potash liquid fertiliser, and that's the exact feed type called for once the first fruits start to swell (every 10-14 days for container-grown plants; in-ground plants in reasonable soil usually don't need it at all).
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing & Germination | 0 | SOWING DEPTH: 13mm (½in) deep when started indoors in small pots; 2.5cm (1in) deep when sown direct outdoors, two or three seeds per station at least 90cm (3ft) apart, thinned to the strongest seedling (RHS). TIMING: sow indoors in April or early May for an earlier, more reliable crop; sow direct outdoors from late May or early June once the soil has warmed and frost risk has passed (RHS). GERMINATION: needs 18-21°C (65-70°F); frost-tender at every stage and must never be sown or planted out while frost is still likely. |
| Vegetative Growth & Planting Out | 3 | SPACING: harden off indoor-raised plants and plant out, or thin direct-sown seedlings, to at least 90cm (3ft) apart -- allow roughly one square metre per plant (RHS). Water at the base rather than over the leaves to reduce the risk of grey mould and powdery mildew, and keep the soil consistently moist (RHS; Clemson: moisten soil to a depth of 6in with a uniform moisture supply). |
| Flowering & Pollination | 6 | Plants are monoecious, carrying separate male and female flowers on the same vine. Male flowers appear first and lack a swelling behind the petal; female flowers have a miniature fruit already visible at the base (UMD). Bees normally carry pollen from male to female flowers; in cool, dull early-summer weather insect activity drops and fruit can fail to set or rot off while small -- this resolves as the weather warms, or can be corrected by hand-pollinating: transfer pollen from a freshly opened male flower onto the stigma of a female flower with a soft brush, or press the two flowers together (RHS; UMD). Feed container-grown plants every 10-14 days with a high-potash liquid fertiliser once the first fruits start to swell; in-ground plants in reasonable soil usually need no feeding (RHS). |
| Fruit Development | 7 | Fruit swells rapidly once set. Keep watering consistent -- irregular watering and poor pollination are the main causes of fruit rotting or failing to develop. Watch the foliage for the powdery, dusty white coating of powdery mildew and fuzzy grey growth of grey mould, both encouraged by still, humid air and overhead watering (RHS); good airflow and watering at the base help prevent both. |
| Ripening & Harvest | 8 | HARVEST: cut courgettes while small, tender and full of flavour, at 10-12.5cm (4-5in) long, using a knife rather than pulling to avoid damaging the plant (RHS). Check plants daily once cropping begins and pick every couple of days -- a single healthy plant can produce three or four fruits a week in good weather; regular picking keeps more fruit coming, while a fruit left on the plant swells into a marrow and slows further production (RHS; Clemson). No storage method is given by RHS; Clemson recommends refrigerating in a plastic bag for up to a week. |
Soil & Growing Conditions
Harvest & Storage
Diseases
Pests
Pollination
Honeybees Apis mellifera
RHS: "Pollination is usually carried out by insects", with honeybees named as the main pollinators. Poor fruit set follows "Lack of pollination due to low activity of pollinating insects, mainly honeybees, during periods of poor and cold weather"; symptoms are that "Young fruitlets are aborted and will drop off" and "The flower end of the fruit will often shrivel up and start rotting". Growing under cover limits insect access. Hand-pollinate by picking a male flower (no fruitlet at its base), removing the petals to expose the anthers, and pressing it into the centre of the female flowers -- "One male flower will pollinate several female flowers".
Plan your Zucchini (Courgettes) planting
Timing for Zucchini (Courgettes) follows soil temperature and frost, not the calendar date. The Global vegetable planting calendar explains the method. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Zucchini in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
Sources
These 3 sources are specific to this region. The full list of 18 sources behind this guide (Clemson Cooperative Extension, FAO EcoCrop, Global Biodiversity Information Facility (GBIF) and others) is in the references of our UK guide to courgettes; they describe the plant itself, which is the same wherever it grows.
Nutrient Issues
Frequently Asked Questions
How long do courgettes take to grow?
Typically 55 days after planting out, depending on cultivar and growing conditions.
What soil pH do courgettes need?
A pH of about 6–6.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect courgettes?
Our data links 9 diseases and 10 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.
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How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against international horticultural research and extension sources. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
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Last verified 2026-08-06
Where To Go From Here
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Plan the next step
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