Zucchini
Cucurbita pepo
Prolific summer squash that produces abundant harvests from just a few plants. Harvest young for best flavor and texture.
Overview
Companion Planting
Corn
Nasturtium
Pea
Marigold
Borage
PotatoToxicity
Generally non-toxic to humans, dogs, and cats (ASPCA-listed as safe); however, bitter-tasting fruits may contain elevated cucurbitacins from cross-pollination with wild cucurbits, which can cause nausea, vomiting, and diarrhea — discard any bitter-tasting fruit.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Apply a 5-7 cm layer of mulch around plants to retain moisture, regulate soil temperature, and prevent soil-borne disease splash onto lower leaves.
Common Pests
Squash Vine Borer
Symptoms: Sudden wilting of individual vines, sawdust-like frass at the base of stems, and yellowing leaves.
Treatment: Slit the affected stem lengthwise to remove the larva, then mound moist soil over the cut to encourage re-rooting.
Prevention: Cover young plants with row covers until flowering; wrap the base of stems with aluminum foil or nylon to block egg-laying.
Squash Bug
Symptoms: Yellow speckling on leaves that turns brown and crispy; wilting vines; clusters of bronze eggs on leaf undersides.
Treatment: Hand-pick adults and egg masses; apply neem oil or insecticidal soap to nymphs.
Prevention: Remove plant debris in fall to eliminate overwintering sites; use companion planting with nasturtiums or radishes to deter them.
Aphids
Symptoms: Curled or distorted new growth, sticky honeydew residue on leaves, and sooty mold development.
Treatment: Spray with a strong jet of water to dislodge them, or apply insecticidal soap or neem oil.
Prevention: Encourage natural predators such as ladybugs and lacewings; avoid excessive nitrogen fertilization that promotes soft growth.
Common Diseases
Powdery Mildew
Symptoms: White, powdery coating on upper leaf surfaces starting on older leaves; affected leaves yellow and die off, reducing fruit production.
Treatment: Apply a potassium bicarbonate spray or sulfur-based fungicide at first sign of infection; remove heavily affected leaves.
Prevention: Ensure good air circulation by proper spacing, avoid overhead watering, and choose mildew-resistant varieties.
Downy Mildew
Symptoms: Angular yellow patches between leaf veins on the upper surface; purplish-gray fuzzy growth on leaf undersides in cool, wet weather.
Treatment: Apply copper-based or neem-oil fungicide for mild infections; remove and discard heavily infected plants.
Prevention: Use drip irrigation instead of overhead watering, space plants widely for airflow, and select resistant cultivars.
Blossom End Rot
Symptoms: Dark, sunken, leathery patches at the blossom end of developing fruit that enlarge as the fruit grows.
Treatment: Remove affected fruit; apply calcium (gypsum) to the soil and maintain consistent, even watering to improve calcium uptake.
Prevention: Test soil and amend with calcium before planting; mulch to keep soil moisture steady and avoid irregular watering cycles.