Cucumbers Growing in a Greenhouse

As one of the most refreshing and versatile fruits in the world, cucumbers are something of a gardener’s favourite. However, while they may be a popular plant, they certainly aren’t without their problems and if you have ever tried to grow them in a greenhouse, you will likely be familiar with how delicate these fruits are.

Cucumber plants may fall victim to a variety of diseases and parasites. If left untreated, your entire cucumber crop could be ruined. But the good news is that there are things you can do to prevent these problems and fix them should they occur.

In this short guide, we will be looking at the most common cucumber problems and giving you some viable ways to solve them as well as looking at some handy growing tips to get the most out of your cucumber crop.

What Are The Most Common Cucumber Problems?

Cucumbers are best grown by sowing seeds directly into the ground in your garden. However, some people prefer to use transplants from their greenhouse but it is worth keeping in mind that this could result in some stunted growth since cucumbers are highly susceptible to transplant shock.

If you want to avoid this and grow from seed but find that the growing season is too short owing to your location, it is best to choose faster-growing varieties.

However, many gardeners prefer to grow their cucumbers inside a greenhouse and here is where you may notice that the cucumbers do not grow very large. This is likely because of a lack of pollination. These plants require heavy pollination which may not be as likely in the greenhouse, even if you are leaving the door open to allow pollinators to enter.

You can try to lure more pollinators in by growing plants that will attract them such as black-eyed Susans, basil, dill and sunflowers, among others. It is also vital that you don’t use pesticides on your plants. But even if you are able to establish healthy growth inside the greenhouse, there may be further problems that ensue.

If you see the beginnings of a cucumber and they seem to wilt and die, you can read what to do about it here!

Lack of Water

One of the biggest mistakes made by rookie gardeners trying cucumbers for the first time is that they simply don’t provide the plants with enough water. Cucumbers have an extremely high water content and if you regularly keep one in your kitchen, you will notice how quickly it can dry out. The same applies to the plant.

When you are growing cucumbers in containers, you will need to pay close attention to how much water they are receiving. Whereas some plants run the risk of being overwatered, you can’t give a cucumber too much.

It is no use simply splashing a little water over the leaves and hoping for the best, you need to spend a little more time tending to your cucumbers if you want them to thrive.

Make sure that you direct the flow of water into the surrounding soil and allow it to soak all the way through to the bottom of the container before you stop the flow.

Signs that your cucumber plants may not be receiving enough water might include wilting, discoloured leaves and slower growth.

Lack of Nutrition

As well as providing the cucumbers in your greenhouse with a lot of water, you will also need to ensure that they receive the correct nutrition. While cucumbers that are grown in the ground will do well with a helping of mulch, those grown in containers in the greenhouse will need a regular dose of organic fertilizer.

Furthermore, you must ensure that you are using top-quality potting soil. If you notice that your plants aren’t flourishing, trying a different potting mix may solve the problem.


One of the most disheartening things as a gardener is finding your beloved plants affected by disease or mites. But, even under the cover of a greenhouse, these things are still entirely possible. There are several things that could affect your cucumber plants and while some are curable others will require you to start from scratch.

Cucumber Mosaic Disease

While it may have a fancy name, this infection will effectively end the life of a cucumber plant. This disease is spread by aphids which can be the bane of a gardener’s life and will cause problems both in and out of the greenhouse.

The key signs of this disease are that the cucumber plant will stop growing and the leaves will develop a mosaic-like pattern that is yellow in colour. It is important that you discard the plant but also make sure to wash your hands before touching other plants as this can be incredibly contagious.

Powdery Mildew

You may walk into the greenhouse one day to find that the leaves of your cucumber plants are covered in a thin white powder that closely resembles talc. In this case, you can be sure that powdery mildew is affecting them. Many gardeners struggle with this problem when growing cucumbers but the good news is that it is largely cosmetic.

However, if the powdery mildew becomes very heavy, this can make photosynthesis difficult and you may notice that the plant’s growth is stunted.

That being said, there are many varieties of cucumber, such as Jackson and Eureka, that are more resilient to this disease. If you do notice that this is a problem, there are fungal treatments that you can use to relieve your plants of mildew.


Cucumbers are very fragile and they are also susceptible to some pests that will happily eat your fruits before you get the chance to enjoy them for yourself. 

Red Spider Mites

According to the Royal Horticultural Society, red spider mites are one of the most problematic insects for greenhouse plants. It is therefore not surprising that if you choose to grow your cucumbers in the greenhouse, they may become a victim of these tiny animals.

Typically, red spider mites will affect the plants when the weather is warmer and they will cause the leaves to take on a rusty appearance. However, there are many treatments that can be purchased for this problem and you can also remove the affected leaves to improve the overall health of the plant.


Another common problem with cucumbers is the whitefly. These small flies that are very closely related to the aphid will suck the sap from the plant which will then result in a black residue, resemblant of soot. In turn, this can significantly stunt the growth of the plant.


While cucumbers are an incredibly popular plant among British gardeners, they aren’t without their problems. These plants will typically thrive best when planted in the ground but it is possible to grow them in a greenhouse. However, you must be prepared to face some issues, most of which are fortunately easily remedied.

Garden Doctor Trev

Garden Doctor Tips

“Leave your greenhouse door open for parts of the day to let the pollinators in or you will have to pollinate the buds by hand!”

“Don’t be tight with your watering schedule, cucumbers need a lot of water in order to swell!”

“Don’t use any chemicals or pesticides on your cucumbers!”

“Grow sunflowers in your garden to attract plenty of bees and other pollinators that will pollinate your cucumbers!”

Frequently Asked Questions

Why are my cucumbers dying?

There are various reasons that your cucumbers could be dying. If they appear very small and seem to wither and die, it is likely due to lack of pollination. Other things that can cause plants to die are various pests and disease. 

Do cucumbers need a lot of water?

Yes, cucumbers require a lot of water once the fruits have set. Cucumbers are mostly made of water so giving them plenty to drink will help them swell and grow large. 

Are cucumbers easy to grow?

Cucumbers are quite fragile and are not self-pollinating which makes them a little trickier to grow for the average beginner. Once you have an idea of what you are doing, however, you will be able to grow and enjoy cucumbers with ease. 

About Me

Hi, I’m Trev and I’ve been growing things since I can remember. When I was younger, I grew up on a farm, so I have always been around plants and animals. After studying horticulture at university, I decided to start my own nursery which I have run now for 25 years. In my spare time, I run this website – which is a resource for people who want to learn more about their gardens.

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