Powdery mildew
Powdery mildew can be a problem during hot, dry spells. It’s a fungal disease that shows up as a powdery white coating on the foliage.
Keep the soil moist and avoid getting leaves wet while watering. Ensure good air circulation around the plant and make sure it doesn’t suffer stress through over or under watering.
Once it really heats up, give the plants a weekly dousing with chive or comfrey tea, which is a brilliant organic anti-fungus treatment made from rotted-down chive or comfrey leaves. Liberally sprinkle them over the plants and that will really keep mildew at bay for another two or three weeks before the end of the season.
Verticillium wilt
Verticillium wilt is relatively uncommon, but the fungal disease can affect cucumbers, infecting the plants from the roots. Signs include wilting leaves, yellowing leaves and a dieback. The fungal disease lives in the soil, so you need to remove the plant with any soil attached to the roots and dispose of it.
Whitefly
These small white pests can be a particular issue for greenhouse-grown cucumbers. You’ll be able to see them on the leaves and they suck the sap of the plant. A healthy plant that isn’t under stress (from over or under watering, for example) should be able to withstand the attack. There are sticky sheets that can attract whitefly and these can be installed around your pots, but they trap good insects too. Basil and marigolds also make great companion plants, either deterring or luring away whitefly and aphids. And you can try Whitefly Control Encarsia that can be hung around the plants.
Cucumber mosaic virus
If you notice yellow mottling on the leaves and stunted growth, the symptoms could indicate cucumber mosaic virus. The cucumbers might also be bitter to taste with puckered spots on the skin. It is most commonly passed on to the plant by aphids, so keep an eye out for these and remove them from the plant as soon as you see them. Clean any tools you’ve used around the plant to avoid transmitting the virus to other plants in the garden.
What are the problems when growing cucumbers in a greenhouse?
Whitefly can be a problem for glasshouse-grown cucumbers. It’s also important to keep on top of watering, daily at the height of summer, to ensure they thrive. But greenhouse-grown cucumbers give higher yields than those grown outdoors, so the efforts can be worth it.
Why are my cucumber leaves turning yellow?
A likely cause is over watering. Ensure they are watered and fed regularly to avoid a nutrient deficit. Alternatively, it could be a symptom of cucumber mosaic virus.
Why are my cucumbers turning yellow?
Overripe cucumbers begin to turn yellow. Harvest them young when they are still completely green.
Why are my cucumber plants wilting?
Wilting can be a sign of a stressed cucumber plant that is being over or under watered. Cold temperatures can also lead to wilt. The worst case scenario is verticillium wilt.
Why are my cucumber plants turning brown?
Browning leaves can be the eventual result of any of the pests, fungal diseases or viruses that can affect cucumber plants. Try to identify the problem and resolve it if possible, and remove any affected leaves.
