Common Cucumber Problems

Common Cucumber Problems & How To Fix Them

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Cucumbers are not meant for these shores, which is why they are often grown in greenhouses. This makes them susceptible to a few issues because of the confined growing environment.

But if grown outside, they often succumb to the weather, particularly in the northern parts of our country.

This can make them bit of a tricky customer, but in truth, I have often found them straightforward to grow.

If you are growing cucumbers for the first time, here are some of the most common issues you might encounter.

Powdery Mildew

Powdery mildew on cucumber
Powdery mildew on a cucumber leaf

Powdery mildew is a fungal disease and affects all plants in the cucurbit family. So that is cucumbers, squashes, pumpkins, courgettes and melons.

It is a common occurrence when growing any cucurbit and normally isn’t much of an issue.

The stronger you plant is, the better it will be able to deal with powdery mildew, so keeping your plants healthy is the best way to fight this issue.

Also, watering the base of the plant and not the leaves is strongly advised. Wet leaves promote the growth of powdery mildew.

You can also spray the leaves with diluted milky water. Some gardeners swear by this method, but I can’t say how well it works as I have never had to resort to it.

Don’t get me wrong, I get powdery mildew on my cucumbers most years, but never bad enough to require intervention.

Red Spider Mites

Red Spider mites
Red Spider mites can kill a cucumber plant if the infestation is severe.

This tiny mite sucks the sap out of your cucumbers and can be a real pain to deal with. This will only be an issue in greenhouses normally as they love warm, dry conditions.

You will notice a severe infestation when you find a fine silk-like webbing on your plant’s leaves like in the photo above.

You have three options to deal with red spider mites.

The first is removing affected plants from the greenhouse, waiting until autumn/winter and giving your greenhouse a good clean in preparation for next year.

You can also get sprays that kill the mites, but I don’t like using pesticides on the crops I plan to eat.

Your final option is the predatory mite Phytoseiulus persimilis this mite feeds on greenhouse spider mites and not plants, so is an excellent way of controlling their numbers without using nasty chemicals.

Mosaic Virus

Cucumber mosaic virus
Aphids usually spread the Cucumber mosaic virus.

Aphids commonly spread this virus. The telltale sign is a random, mosaic-like discolouration of the leaves.

The photo above is a very extreme example, and the leaves often have a paler green discolouration rather than the extreme yellow shown here.

Because this is a virus, I’m afraid there isn’t much you can do for your plant.

The best thing to do is to remove the plant and destroy it, often by burning.

You want to clean your hands after and disinfect any tools that came into contact with the plant. This is because it can spread by contact as well as aphids.

Grey Mould

Grey Mould on a Bean
Grey Mould on a Bean, but it also often affects cucumbers.

This is a mould that usually grows on damaged fruit. This makes it fairly simple to deal with, remove and destroy any cucumbers that have become damaged on the plant.

In the photo above, the mould is on a bean, but it looks the same no matter what it is infecting.

Look for a grey, furry growth. Good ventilation in your greenhouse can reduce the risk of this occurring in the first place.

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  1. My cucumbers have been very slow in developing this year but now have grown with the middle narrow and there is no sign of the middle growing normally, what may have caused this?

    1. I believe this can be caused by them not getting enough water when the central part was developing

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