There are various reasons why cucumbers do not produce fruit. One of them is the lack of pollination by insects. In this case, there are several ways you can encourage fruiting.
There are no more bees? - Then the brush is needed!
Help by hand
Cucumbers grown outdoors are pollinated by wild bees, bumblebees and insects. Varieties that form female and male flowers on one plant are suitable for outdoor planting. Pollen transfer, however, requires warm and dry weather. If the summer is cooler and wetter, the crop yields are lower. In the greenhouse, nature has a limit, because flying pollinators are usually absent in the enclosed space.
strip method
The first flower buds to open on the cucumber plant are usually male. Only later do stronger female flowers develop. Cut off a specimen with stamens and remove the petals. Streak the stamens over the floral organs of the opposite sex.
brush method
With a brush, cucumber blossoms in the greenhouse can be pollinated in a targeted manner. Stroke this over each individual flower. Repeat the process twice a day to encourage fruiting. More and more pollen accumulates between the brush bristles, which distributes it all the better. If you don't have a brush handy, you can use a cotton swab.
shaking method
This variant is less successful because the pollen is not specifically transferred between the flowers. With a dense stock of plants in the greenhouse, the success of shaking is greater than with individual plants. Grasp the cucumber plant directly by the stalk and shake vigorously and gently. The more often you carry out this measure, the higher the success rate.
tips
Open the windows of the greenhouse more often. In this way, pollinating insects can stray into the interior and take over the pollen transmission.
Plant parthenocarpic cucumbers
There are cucumber varieties that develop fruit without any pollination at all. They form exclusively female flowers, which fruit after mechanical stimuli. These are seedless, so such breeds are not suitable for propagation. They prove to need warmth and are often unsuitable for outdoor cultivation.
These are virgin varieties:
- Swing F1: resistant and aromatic, produces high yields
- Loustik F1: good-bearing variety that also thrives outdoors
- Diamond F1: robust and resistant to mildew, suitable for outdoor beds
Good to know
Cultivated forms that are intended for cultivation in the greenhouse do not have to and should not be pollinated. If flying insects stray into the interior, they carry pollen from hermaphrodite flowering outdoor cucumbers. This faulty pollination of parthenocarpic plants poses the risk of malformations. The cucumbers will cripple and get sick. You should therefore pay attention to fly screen protection when you open the windows.