Growing Courgettes Organically: The Most Productive Vegetable

Courgette cells divide and expand at an extremely fast rate once the fruit is fertilised after flowering — under favourable, warm summer conditions the fruit’s diameter can grow several centimetres per day. At the same time, cell walls thicken and the tissue around the seeds begins to become fibrous, causing the characteristic tough, seedy texture — so what was a tender 15 cm fruit in the morning can grow into a 25-30 cm, far less enjoyable marrow by the next day.

Courgette produces single-sex flowers — separate male and female blooms on the same plant — and it can happen that only one flower type opens during a given period, or damp, cool weather suppresses pollinator insect activity. Hand-pollinating transfers pollen from the male flower to the female flower’s stigma using a brush or by directly removing the male flower, ensuring fertilisation even in situations where natural pollination isn’t sufficient or its timing doesn’t coincide with flower opening.

Powdery mildew fungal spores germinate fastest on leaf surfaces that stay damp for extended periods, and since courgette’s large, dense foliage already dries slowly, evening watering keeps the leaves wet all night, creating ideal conditions for infection. Unlike morning or midday watering, when sun and air movement dry leaves within hours, evening moisture combined with dropping temperatures extends the window during which fungal spores can successfully attach and germinate.

Courgette develops a bushy but remarkably expansive canopy — a single plant’s leaves can cover an area 1-1.5 metres across at the peak of the season, providing enough photosynthetic surface for continuous, weekly fruit production. If plants are spaced too closely, neighbouring leaves overlap, reducing airflow (increasing powdery mildew risk) and reducing light reaching individual leaves, ultimately resulting in lower yield per square metre.