GROW grapes in a small greenhouse. Two years ago bunches of flowers
started drying out from the beginning of the flowering period until
most of them dried out completely. The leaves were not affected
at all. Last year I had a very good crop with no problems. But this
year it is back again. Can you help?
splits in the stems of the bunches you sent indicate adverse environmental
conditions are probably the cause rather than disease. In a small
glasshouse during spring you often get quite dramatic changes in
temperature when the weather can change from dull and cloudy one
minute to bright sun the next. And the temperature can also drop
quite low on cool spring nights.
Fluctuations in water,
such as the soil drying out or being excessively wet on occasions,
could also contribute to the problem. Try to ensure your greenhouse
is well ventilated to prevent it getting too hot during the day
- apply a light coat of shading paint if necessary.
Try to maintain even
soil moisture. Don't allow the soil to dry out, but also try to
prevent seepage, from heavy rain outside, percolating through into
the greenhouse soil which can create wet soil conditions. Some commercial
grape growers have drains around their greenhouses to prevent this.
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.