Courgette (zucchini) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun, six to eight hours daily, for vigorous growth, plentiful flowers and good fruit set. Shade gives leggy plants, fewer flowers and poor pollination; warmth and bright light are essential for this heat-loving crop. If your only bright window faces south, that's perfect for courgette — same window any aroid would fry on.

Watering

Crops like courgette reward consistent watering — water generously and consistently; deeply every 2-3 days in summer. The mistake is the daily light sprinkle: it never reaches the deeper roots. A long soak twice a week beats a five-minute splash every day. A thirsty crop with large leaves that loses water fast in heat. Water deeply at the base, never overhead, to keep fruit swelling and avoid powdery mildew. Erratic watering causes flower drop and misshapen, bitter fruit.

Soil and pot

Courgette grows best in very rich, moisture-retentive, free-draining soil, ph 6.0-7.0. Wants deep, fertile soil loaded with organic matter to feed heavy fruiting and hold moisture. Plant on or beside a compost-enriched mound or planting pocket; good drainage prevents the stem and root rots this crop is prone to. 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

Courgette sits happiest at around 50-70% humidity and 18-27°C (65-80°F). Tolerates outdoor humidity but wants airflow; the big leaves and dense growth invite powdery mildew in warm, humid, still conditions. Space plants, water at the base, and keep foliage dry to slow mildew. 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 courgette sparingly. A heavy feeder. Plant into compost-rich soil, then once fruiting begins feed every 1-2 weeks with a high-potassium tomato-type liquid feed to sustain flowering and fruit set. Too much nitrogen gives lush leaves but few fruits. 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 courgette in the Growli community. Each is annotated with the most common cause so you know where to start.

• Powdery mildew — White powdery coating on leaves is almost inevitable late in the season, weakening plants. Space for airflow, water at the base, remove the worst leaves, and choose mildew-resistant cultivars.
• Poor fruit set and rotting tips — Young fruit shrivels and rots at the tip when cold, wet weather or lack of pollinators prevents pollination. Encourage pollinators, hand-pollinate if needed, and pick fruit young to keep plants productive.
• Cucumber mosaic virus — Yellow-mottled, distorted leaves and stunted, deformed fruit signal this aphid-spread virus. There is no cure; control aphids, remove and destroy infected plants, and grow resistant varieties.
• Slugs on seedlings — Slugs and snails can destroy young transplants overnight. Protect seedlings with barriers and traps, plant out only well-grown plants, and keep the surrounding area clear of debris.

Propagation

From seed. Sow seed on edge to deter rot, indoors in pots 3-4 weeks before the last frost or direct once soil is warm (above 15°C). Harden off and transplant after all frost risk at 90 cm spacing. Plants are frost-tender, so never sow or plant out before the soil and nights are reliably warm. 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

Courgette is pet-safe. Zucchini/courgette squash (Cucurbita pepo) is directly listed by the ASPCA as non-toxic to cats, dogs and horses. Eating plant material can still cause mild GI upset, and rare bitter, cucurbitacin-high fruit should be discarded; otherwise the flesh is safe in moderation. Note whole raw fruits are a choking or obstruction hazard for dogs. 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).

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.

Courgette deep-dive guides

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

• Courgette watering schedule
• Courgette light requirements
• Best soil mix for courgette
• Courgette fertilizing guide
• When to repot courgette
• How to propagate courgette
• Courgette growth rate & size
• Courgette cold hardiness
• Courgette temperature & humidity
• Is courgette toxic to cats & dogs?
• Is courgette toxic to cats?
• Is courgette toxic to dogs?

Featured in these plant shortlists

Courgette qualifies for 2 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best pet-safe trailing & hanging plants — Trailing and climbing plants the ASPCA lists as non-toxic to cats and dogs — safe for shelves and hanging pots in a pet home.
• Best pet-safe low-maintenance plants — Non-toxic to cats and dogs and forgiving of forgotten watering — the easiest safe choices for a busy pet household.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Courgette is also known as courgette, zucchini, and summer squash.

• Tomato care — light, water and common problems
• Pepper care — light, water and common problems
• Cucumber care — light, water and common problems
• All 2464 plant care guides in the Growli library