How to Grow Courgette

In the Three Sisters system, sweetcorn provides vertical structure for beans while courgette leaves form a dense ground canopy that shades out weeds and locks in soil moisture, reducing watering needs by up to 30%. The complementary root depths — corn's deep fibrous roots versus courgette's shallower spread — mean minimal underground competition.

Nasturtiums serve as a sacrificial trap crop, luring aphids — particularly Aphis fabae and Myzus persicae — away from courgette plants with their glucosinolate-rich foliage and bright flowers. Position nasturtiums at the bed perimeter and check weekly; heavy infestations can be removed entirely with the nasturtium plant.

French marigolds (Tagetes patula) produce alpha-terthienyl in their roots, a compound toxic to nematodes in the soil, while their bright orange and yellow flowers attract hoverflies and bees that pollinate courgette's large, brief-lived blooms. Plant one marigold clump per courgette hill to concentrate both benefits.

Courgettes and potatoes both demand high levels of potassium and phosphorus and compete aggressively for soil moisture with their extensive root systems, reducing yields of both when grown together. Potatoes can also harbour Phytophthora and Verticillium that, while not primary courgette pathogens, can weaken plants under stress; keep them at least 60 cm apart.