courgettes not producing
growing miniature pumpkins in a reasonably sunny spot. The pumpkins
start to form but soon rot. I've also had the same problem with
my courgettes. Any suggestions?
possible the flowers are being infected with a fungus such as grey
mould, which can grow on the old petals of a flower as they die
off, especially in cool, wet conditions. It grows readily on soft
plant tissue and, once established, spreads rapidly to destroy immature
You could spray with
a fungicide, but you'd need to be aware of the withholding period,
which is the time that should elapse between spraying and harvesting
the fruit. Courgettes usually need picking several times a week,
so you probably would want to avoid spraying them.
The good news is that
with warmer and drier weather, the fungus is less likely to be a
Another cause could be
lack of pollination. Courgettes and pumpkins have separate male
and female flowers and they rely on insects and bees to transfer
the pollen. Cool weather can deter bees and other pollinators, but
more recently varroa mite has killed off many wild bee hives and
reduced the number of hives kept by amateur beekeepers, so there
are fewer bees around to pollinate our garden crops.
If the female courgette
or pumpkin flower doesn't get pollinated, it will eventually die
off and rot, even though a small fruit may have started to develop.
You can overcome this problem by hand pollinating the flower. The
female flower has a small swelling immediately behind the flower,
the male has none. Simply break off the male flower, remove its
petals and rub the pollen-bearing part (the stamens) against the
central part (stigma) of the female flower. You can pollinate several
female flowers with the pollen from one male flower.
Gardener, Issue 190, 2005, Page 25
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.