Nine times out of ten the plant is simply young and producing only male flowers. Courgettes carry separate male and female flowers, and a young plant throws all-male flowers first — the females, each with a tiny courgette already swelling behind the petals, follow a week or two later. Fruit only sets once both kinds are open at the same time and a bee (or you) carries pollen between them. If female flowers are forming but the little fruit shrivels instead of growing, then it's almost always poor pollination or too much nitrogen.

Check which flowers you actually have first

Before you assume anything's wrong, look closely at the flowers:

  • Male flowers sit on a plain, thin stalk with nothing behind the petals.
  • Female flowers have a miniature courgette right behind the bloom.

If every flower is on a bare stalk, your plant is just at the male-only stage. That's completely normal, and there's nothing to fix — give it another week or two and the females will come.

The most common reasons

  1. Only male flowers so far. As above: the usual answer, and no cause for worry.
  2. Too much nitrogen. In a temperate garden, where bees are generally active through summer, over-feeding is a more likely culprit than pollination failure. A lush, dark-green, leafy plant with plenty of foliage but few flowers or little fruit has usually had too much high-nitrogen fertiliser, which drives leaf growth at the expense of fruit.
  3. Poor pollination. Less common here than in colder zones, but it still happens in a cool, wet spell — a female flower is only receptive for a few hours on the morning it opens and needs several pollinator visits, so a run of grey days at the wrong moment can leave fruit unset.
  4. Not enough sun, or overcrowding. Shaded or crowded plants flower poorly and are harder for bees to work.

Because bees usually do their job in summer here, the honest order of suspicion is: is it just male flowers? → have I been over-feeding? → and only then → is it a pollination miss?

Timing

Courgettes are frost-tender, so they go in after the last frost — the temperate frost period runs April to November. Sow November to February and you'll be harvesting January to April. A plant sown at the right time has a long enough warm season that a slow start on fruit is rarely fatal; if yours went in late, give it time before worrying.

What to do now

  • If you only have male flowers, wait a week or two for the females.
  • If females are dropping unset, hand-pollinate: pick a male flower, strip its petals back, and dab its central column into the centre of each open female flower on a sunny morning before about 10am. One male will do several females — a small dry paintbrush works too.
  • Ease off the nitrogen once the plant is flowering. Switch to a balanced or potassium-richer feed so energy goes into fruit rather than leaves.

What to change next season

  • Grow at least two plants for a reliable pollen supply — our planting notes recommend it for exactly this reason.
  • Give the bed full sun and space plants about a metre apart.
  • Keep watering consistent, and go easy on rich nitrogen feeds once flowering starts.

Cultivars like Black Beauty, Cocozelle or the Black Coral F1 hybrid (all Kings Seeds NZ) are reliable croppers — variety is rarely the reason for no fruit, so fix the flowering and feeding first.

Seeing flowers drop as well? See Why Are My Courgette Flowers Falling Off in NZ Temperate?, or explore the full NZ Temperate Planting Calendar →.