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Plant care

Zucchini / courgette (courgette) care

Cucurbita pepo

Also called courgette, summer squash, marrow (mature fruit).

RHS H2 (tender)USDA Grown as an annual in zones 3-11Pet-safeIndoor 60-90 cm tall and 1 m+ spread

Watering rhythm

Direct sun (at least 4-6 hours)

Deep watering twice a week

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Light

Direct sun (at least 4-6 hours)

Soil

Rich, well-drained loam

Humidity

40-70% (outdoor)

Temp

18-29°C

Pet safety

Pet-safe

Mature size

60-90 cm tall and 1 m+ spread

Care at a glance

Light

Most houseplants will scorch where zucchini / courgette thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. 6-8 hours of direct sun. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

For zucchini / courgette in the ground or in a bed, aim for deep watering twice a week. Soak the root zone rather than misting the foliage; deep, less-frequent watering trains roots downward and produces a more drought-resilient plant by mid-season. Aim for 3-5 cm of water per week; consistent moisture prevents bitter fruit and blossom-end rot.

Soil and pot

Zucchini / courgette grows best in rich, well-drained loam. Compost-rich beds; pH 6.0-7.0. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Zucchini / courgette sits happiest at around 40-70% (outdoor) humidity and 18-29°C (65-85°F). Outdoor humidity rarely matters. If you keep the room above 18 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed zucchini / courgette sparingly. A balanced feed at planting; switch to a high-potash tomato feed once flowering starts. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on zucchini / courgette in the Growli community. Where a problem matches one of our diagnostic guides, click through for the full step-by-step recovery plan written for zucchini / courgette specifically.

  • Powdery mildew — Common in late summer; water at soil level and choose resistant varieties.
  • Blossom-end rot — Inconsistent watering, not a calcium deficiency.
  • Female flowers but no fruit set — Poor pollination — hand-pollinate in the morning if bees are scarce.
  • Squash vine borer — Larvae tunnel inside stems; rotate planting site and protect with row cover.
  • Yellow leaves — Nitrogen depletion in heavy producers; side-dress with compost.

Companion plants

Zucchini / courgette pairs well with Bean, Corn, Marigold, and Nasturtium. These are species with similar light and water needs, so you can grow them in the same bed or container without conflict.

Propagation

Sow seed indoors 3-4 weeks before the last frost, or direct-sow once soil is above 16°C. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Zucchini / courgette is pet-safe. Cucurbita species are not listed as toxic by the ASPCA. Rare bitter fruits caused by cucurbitacin should not be eaten by people or pets. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435 in the US, or Animal PoisonLine on 01202 509 000 in the UK).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Zucchini / courgette care — frequently asked questions

What is the common name for Cucurbita pepo?

Cucurbita pepo is most commonly called Zucchini / courgette, but it is also known as courgette, summer squash, marrow (mature fruit). The names refer to the same species, so care instructions for Zucchini / courgette apply identically to anything sold as courgette.

How much light does zucchini / courgette need?

Zucchini / courgette grows best in direct sun (at least 4-6 hours). 6-8 hours of direct sun.

How often should I water zucchini / courgette?

Water zucchini / courgette deep watering twice a week. Aim for 3-5 cm of water per week; consistent moisture prevents bitter fruit and blossom-end rot. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is zucchini / courgette toxic to cats and dogs?

Zucchini / courgette is pet-safe. Cucurbita species are not listed as toxic by the ASPCA. Rare bitter fruits caused by cucurbitacin should not be eaten by people or pets.

What USDA hardiness zone does zucchini / courgette grow in?

Zucchini / courgette is rated for USDA zone Grown as an annual in zones 3-11 and RHS hardiness H2 (tender). Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Zucchini / courgette deep-dive guides

Every aspect of zucchini / courgette care, each with its own calibrated guide:

Featured in these plant shortlists

Zucchini / courgette qualifies for 1 curated Growli shortlist — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Zucchini / courgette is also known as courgette, summer squash, and marrow (mature fruit).