© Silar · CC BY-SA 4.0 · Commons
Zucchini
CautionZucchini · (Cucurbita pepo subsp. pepo convar. giromontiina)
Gourd family (Cucurbitaceae)
Description
The courgette is a cultivated form of the field pumpkin in which the fruit is picked young — while skin and seeds are still soft enough to eat. The plant grows bushy rather than trailing and carries separate male and female flowers; the female ones are recognisable by the small swelling just beneath the bloom. Harvest runs from July to October, ideally at 15 to 20 centimetres, since large fruits turn watery and seedy. The yellow flowers are a delicacy in their own right, stuffed and fried. The flesh is very high in water and low in calories, supplying potassium, vitamin C and a little beta-carotene. One warning applies to courgettes grown from home-saved seed: back-crossing with ornamental gourds can produce bitter cucurbitacins — any fruit that tastes bitter belongs straight in the bin.
Zucchini (Cucurbita pepo subsp. pepo convar. giromontiina) is an early-ripening summer-squash subvariety and one of the most widely used fruit vegetables in Mediterranean and Central European cuisine. The elongated cylindrical fruit (usually green, occasionally yellow) is harvested unripe (15-25 cm) while skin and seeds are still tender. It is low in calories (approx. 17 kcal/100 g), water-rich (approx. 94 %) and provides vitamin C (approx. 17 mg/100 g), B vitamins (B6, folate), potassium (approx. 261 mg/100 g) and manganese. Uses: fried, grilled, steamed, stuffed, pickled, as soup, in ratatouille or raw in thin slices in salads.
The large, bright yellow-orange zucchini flowers are edible and considered a delicacy in Italian cuisine — 'fiori di zucca'. Preferably the male flowers on long stalks are picked (female flowers sit at the fruit base and reduce yield). Classic preparation: stuffed with ricotta, mozzarella, anchovy and herbs, deep-fried in a light batter (pastella). Also raw in salads or in risotto and pasta. Constituents: carotenoids (beta-carotene, lutein), vitamin C, folate. Very short shelf life (max. 24 hours), use the same day.
Seeds of mature (overgrown) zucchini fruits are also edible and can be processed like pumpkin seeds: extract from the fruit, thoroughly remove fibres, wash, dry and roast at low temperature (max. 150 °C). They provide protein, fatty acids (linoleic and oleic acid), zinc, magnesium and vitamin E. As zucchini is usually harvested unripe, this use is rare in modern cuisine — historically, however, it was a form of leftover use in Mediterranean farm households.
In Mediterranean folk tradition, zucchini is considered a 'cooling' summer food due to its high water content (approx. 94 %) and easy digestibility — recommended in summer heat, sensitive stomach and as light diet after gastrointestinal complaints. Classic preparation as a light stew (e.g. southern Italian 'zucchine in umido') or as a pureed soup for children and convalescents. Dietary fibre (approx. 1 g/100 g, predominantly pectin and cellulose) supports regular digestion without irritating the gut.
A simple folk use: thin zucchini slices briefly applied to irritated or mildly sun-stressed skin — the high water content and polyphenols are said to have a cooling effect. Comparable to cucumber slices over the eyes, the application is practised as a home remedy in Mediterranean countries. No clinical evidence; not suitable for open wounds or second-degree sunburn.
Sources: [5]
IMPORTANT — Toxic Squash Syndrome (TSS): Bitter-tasting zucchini must be discarded IMMEDIATELY and NOT eaten. Bitter compounds (cucurbitacins) have been largely bred out of modern cultivars but can reappear through mutations, stress conditions or cross-pollination with ornamental gourds. A single bitter bite can cause severe nausea, vomiting, cramping abdominal pain, bloody diarrhoea and circulatory collapse within 30 minutes to several hours. In Germany in 2015, a 79-year-old man died from a bitter zucchini casserole made from home-saved seeds (Heidelberg case). Rule: taste a small raw piece before cooking — if bitter, discard the entire fruit. Keep home seed-saving separate from ornamental gourds. ASPCA classification (accessed 2026-08-10): non-toxic to dogs. The ASPCA classifies the whole genus this way.
Zucchini as food is safe in pregnancy and lactation — low in calories, rich in vitamins and folate. The TSS warning naturally also applies here: discard any bitter-tasting fruit, as cucurbitacins can cross the placenta and may be embryotoxic.
Zucchini is a well-tolerated, alkaline vegetable during lactation. No known effects on milk production or the infant.
Peeled, soft-cooked zucchini is a classic complementary food vegetable from the 5th-6th month — mild in flavour, easily digestible, low-allergenic. TSS precaution: always taste a small raw piece before preparing for children; do not feed if bitter (children are particularly sensitive to cucurbitacins).
Contraindications
- Never eat bitter-tasting zucchini — suspicion of elevated cucurbitacin concentration (Toxic Squash Syndrome).
- Known hypersensitivity to cucurbit plants (Cucurbitaceae).
- Do not save seeds from plants that grew near ornamental gourds — back-crossing can increase cucurbitacin content.
- Larger amounts may cause diarrhoea in dogs and cats; otherwise cooked zucchini in normal household amounts is safe for pets.
- Do not consume sprouting zucchini seeds as sprouts — as with other Cucurbita pepo seeds, a toxic substance in the embryo is described.
Harvested part: young fruits (summer)
- Time of day:
- Zucchini is an early-ripening subvariety — harvest begins approx. 8 weeks after sowing. Harvest continuously while fruits are small and tender (15-25 cm length, skin glossy and slightly dentable with a fingernail). Daily harvesting stimulates new fruit set; overripe fruits (>30 cm, matt skin, hard seeds) slow the plant down. Cut at the stalk base with a sharp knife — do not pull. Taste test before cooking: try a small raw piece — discard entire fruit if bitter (TSS suspicion).
- Drying:
- STORAGE: Zucchini is NOT storable like winter squash. Use fresh within 5-7 days in the vegetable drawer of the refrigerator (8-10 °C, not below 7 °C — chilling injury). Preservation: freeze (sliced or grated, blanch briefly first), pickle (sweet-sour as 'zucchini pickles'), dry (in thin slices in dehydrator at 50-60 °C until crisp) or preserve in jars.
- Storage:
- Cool (8-10 °C), not ice-cold, do not store next to ethylene-producing fruits (apples, tomatoes) — accelerates wilting.
- Time of day:
- Pick zucchini flowers in the early morning before 10 a.m. while the flower is still open and the sun has not yet fully reached the bed — afterwards flowers close and become soft. Male flowers have long thin stalks without fruit set (yield-neutral); female flowers have a thickened fruit base (picking them reduces yield). Carefully remove pistil and stamens before preparation, check inside the flower for insects.
- Drying:
- STORAGE: Zucchini flowers are extremely delicate and should be processed on the day of harvest. Short-term storage (max. 24 hours) in the refrigerator in a damp paper towel wrap in an open plastic box. Do not wash before storage — water causes the delicate petals to disintegrate.
- Storage:
- Cool, wrapped damp, max. 24 hours — best to process directly after morning harvest.
- Cucurbitacine (Triterpene)BitterContent: Spuren in modernen Sorten; bei Rückmutation oder Hybridisierung mit Zierkürbis stark erhöhtFruit
Tetracyclic triterpenes with intensely bitter taste. Bred out of modern zucchini cultivars (recessive gene 'bi'); can reappear through mutation, drought stress or cross-pollination with ornamental gourds. Cause of Toxic Squash Syndrome (TSS) — even small amounts cause acute gastroenteritis, bloody diarrhoea and circulatory collapse. Taste warning system: discard fruit immediately at any bitter bite.
- Beta-Carotin (Provitamin A)OtherContent: ca. 0,12-0,40 mg/100 g (Frucht); deutlich höher in gelben Sorten und BlütenFruit
Provitamin-A carotenoid, converted to retinol in the body according to need. Present in moderate amounts in green zucchini, significantly concentrated in yellow varieties and especially in the flowers. Important for vision, immune defence and skin health.
- Lutein und ZeaxanthinOtherContent: ca. 2125 µg/100 g (Lutein + Zeaxanthin, Frucht roh mit Schale)Fruit
Oxygen-containing carotenoids (xanthophylls) that accumulate in the macula lutea of the retina, where they act as natural blue-light filters and antioxidants. Adequate intake is associated with lower risk of age-related macular degeneration. Concentrated in the green skin.
- Vitamin C (Ascorbinsäure)VitaminContent: ca. 17 mg/100 g (Frucht roh)Fruit
Water-soluble antioxidant, partly destroyed by heat (loss approx. 30-50 % during prolonged cooking). Involved in collagen synthesis, iron absorption and immune defence. Maximum retention raw or briefly cooked (steamed, wok).
- Folsäure (Vitamin B9)VitaminContent: ca. 24 µg/100 g (Frucht roh)Fruit
Important B vitamin for DNA synthesis, cell division and haematopoiesis; particularly relevant in pregnancy (neural tube development). Heat-sensitive; therefore prepare zucchini gently.
- KaliumMineralContent: ca. 261 mg/100 g (Frucht roh)Fruit
Bulk element with osmotic effect, necessary for muscle and nerve excitability, blood pressure regulation and acid-base balance. A potassium-rich, sodium-poor diet is associated with lower blood pressure (DASH diet).
- MagnesiumMineralContent: ca. 18 mg/100 g (Frucht roh)Fruit
Cofactor for over 300 enzymatic reactions, involved in ATP metabolism, muscle relaxation and bone mineralisation. Zucchini provides moderate amounts; combined with other plant magnesium sources (nuts, whole grains) part of adequate daily supply.
- ManganMineralContent: ca. 0,18 mg/100 g (Frucht roh)Fruit
Trace element, cofactor for antioxidant enzymes (manganese superoxide dismutase) and involved in bone and connective tissue metabolism. Zucchini provides small amounts that contribute to daily requirement.
- [4]MonographUSDA FoodData Central — Squash, zucchini, baby, raw(accessed: 2026-05-27)
- [5]MonographPlants For A Future (PFAF) — Cucurbita pepo (zucchini cultivars)(accessed: 2026-05-27)
- [6]MonographASPCA Animal Poison Control — Yellow-Flowered Gourd (Cucurbita species)(accessed: 2026-08-10)
- [1]WikipediaZucchini (Wikipedia DE)(accessed: 2026-05-27)
- [2]WikipediaZucchini (Wikipedia EN)(accessed: 2026-05-27)
- [3]WikipediaSquash blossom (Wikipedia EN)(accessed: 2026-05-27)
🤝 Permaculture Partners
In your garden, this plant acts as:
✨ Best symbiotic partners
- 🌿 Onion Classic companion-planting partner.
- 🌿 Borage Borage attracts pollinators to zucchini flowers — more fruits.
- 🌿 Calendula officinalis Classic companion-planting partner.
- 🌿 Phaseolus vulgaris Classic companion-planting partner.
- 🌿 Tropaeolum majus Nasturtium deters squash beetles.
- 🌿 Maize Classic companion-planting partner.
⚠️ Better not planted together
- 🥬 Potato Both heavy feeders — water and nutrient competition.
Source: Helga und Margarete Langerhorst, Mein gesunder Naturgarten (eigene Kuration) | Klassische Mischkultur-Tradition (Three Sisters, Bauernregel)