5 Reasons Why Your Cucumber Leaves Are Turning Yellow And How To Fix It

Growing fruits and vegetables is very rewarding as you can taste products that you know have been grown in your backyard.

Lots of people find growing their fruits and vegetables very therapeutic and rewarding, but it can also come with its difficulties.

5 Reasons Why Your Cucumber Leaves Are Turning Yellow And How To Fix It

When you begin to notice that your cucumber leaves are turning yellow, it is something that needs to be fixed as soon as you notice.

It is important to find the right solution to the problem, but what could be causing your cucumber leaves to turn yellow and how do you fix them?

This article will explain 5 of the reasons why your cucumber leaves are turning yellow and how you can fix them to keep your cucumber plant in the best condition possible.

Find out more about caring for your cucumber leaves below and how you can keep them healthy.

Why Are My Cucumber Leaves Turning Yellow?

There are 5 reasons why your cucumber leaves are turning yellow.

These reasons are that there are soil deficiencies, your plant has picked up a disease, pests have targeted your plant, there are problems with the watering, and there are problems with the sunlight.

All of these problems can cause the leaves of your cucumber plant to become yellow.

As there are 5 reasons for the leaves of your cucumber plant becoming yellow, how can you tell what problem your plant is suffering from? You can find out how to identify the problem with your plant’s leaves below.

5 Reasons Why Your Cucumber Leaves Are Turning Yellow And How To Fix Them

5 Reasons Why Your Cucumber Leaves Are Turning Yellow And How To Fix It

Below you will find more about the reasons why your cucumber leaves are turning yellow and how to fix them.

When you find these problems with your cucumber leaves, you might think that it is beyond your control. However, you can find out how to fix these problems below.

Soil Deficiencies

Having soil that is rich in nutrients is very important for making sure that your plant grows properly. Without the nutrients in the soil, your plant will not be able to thrive and you will find that there are problems with its growth.

You can perform a soil test to see what nutrients your soil is lacking and then add fertilizer to the soil to help your plant grow.

Lacking Iron

You will know if your cucumber plant is lacking iron as the leaves will be yellow but they will have visible green veins.

To fix the problem, you can spray the plant with liquid iron or use granular iron around the roots. This will help to improve the iron levels in the cucumber plant.

Lacking Potassium

If your cucumber plant starts to flower, your plant will be lacking in potassium. This can also be seen if the leaves begin to turn yellow around the edges, so you need to use fertilizer to improve the potassium levels.

This will raise the potassium levels in the soil and help the plant to grow properly as the plant will no longer have a deficiency.

Lacking Nitrogen

When a cucumber plant is lacking nitrogen, it is very common for the leaves to turn yellow. Without the right levels of nitrogen, the plant can die, so the issue must get fixed.

To do this, you need a fertilizer that has a ratio of 5-10-10, but follow the instructions as adding too much can damage the plant.

You will then need to add a teaspoon of ammonium nitrate to the soil when the plant begins to flower and repeat it 3 weeks later.

Adding compost around the soil can also help the plant reach the right levels of nitrogen.

You should then see an improvement in your plant and the leaves should no longer look yellow and should return to their natural color.

Diseases For Cucumber Plants

There are a few diseases that cucumber plants can pick up and it can drastically affect their growth. If your plant becomes infected with one of these diseases, it is important to treat them as soon as possible.

Downy Mildew

The leaves of your plant will have yellow spots and they will eventually begin to turn brown, which is common if your plant is living in a humid environment.

To prevent it from worsening, you should give your cucumber plant space to dry out, use fungicides, and remove any plants that have become infected to prevent the disease from spreading.

Fusarium Wilt

Yellow leaves are also a sign that your plant is suffering from fusarium wilt and the leaves can also begin to wilt. It is caused by fungus and your plant can die within a few days after it has become infected.

Unfortunately, you need to remove your plant if it has become infected as leaving it can cause the disease to spread to other plants.

Cucumber Mosaic Virus

If you spot that the leaves of your plant have patterns that resemble a mosaic, this can indicate that your plant has a cucumber mosaic virus.

This can be caused by aphids and to get rid of the virus, you need to remove the entire plant and the soil to prevent any other plants from becoming infected. The virus can remain in the soil, so do not re-plant in the same soil.


Keeping pests away from your cucumber plant is important as they can begin to eat at the plants and even cause them to develop diseases, so you need to keep them away.

Whiteflies and aphids feed on the sap in the leaves, which can turn the leaves yellow, so spraying the plant with insecticide will keep it protected from pests.

Another cause of yellow leaves is that your plant is infested with potato leafhoppers.

They inject the plant with saliva that eventually turns the leaves yellow, so it is important to keep them away from the plant too.

You can do this by using row covers and spraying the plant with insecticide.

Not Being Watered Enough

When your cucumber plant is not watered enough, this can affect their leaves and they can begin to turn yellow.

It is important to be consistent when watering your cucumber plants as you do not want them to become dehydrated.

You need to make sure that your cucumber plant drains well to avoid the roots from rotting or becoming damaged from them not being able to dry properly.

You should only be watering your cucumber plant with 1-2 inches of water a week to make sure that it is hydrated and there is no risk of dehydration or overwatering.

Not Getting Enough Sunlight

Making sure that your cucumber plant gets enough sunlight is important for making sure that it grows properly.

Cucumber plants love the sunlight, so they need to have at least 6 hours of sunlight a day. Not getting enough sunlight can result in their leaves becoming yellow as the plant will not be able to grow properly.

If you are looking to improve the growth of your cucumber plant, they can thrive on 8 hours of sunlight a day.

They must get the right amount of sunlight to grow properly, otherwise, your cucumber plant will not thrive and the plant could begin to wilt.

Should Yellow Leaves Be Cut Off?

5 Reasons Why Your Cucumber Leaves Are Turning Yellow And How To Fix It

You should never just cut the yellow leaves off the plant and then think that the problem has been solved.

There are many causes for yellow leaves, so you need to treat the problem to make sure that it does not worsen.

In some cases, leaving the yellow leaves to worsen can cause the plant to die, so treating it effectively is important.

If the plant has become infected by a disease, there are some cases where you will need to remove the whole plant.

Not removing the plant can cause other plants to catch the disease, so removing the whole plant is more effective than just removing the leaves.

Cutting the leaves off a diseased plant will not mean that the disease is gone.

Good Companion Plants For Cucumber Plants

Having good companion plants for your cucumber plant is important for continuing to repel insects.

Marigolds and sunflowers are very good at repelling pests from cucumber plants, so you can simply plant them by your cucumber plant to make sure that no pests begin to eat the cucumbers.

Oregano and dill are also good companion plants for repelling insects.

By repelling insects, you will be protecting the plant from being targeted by pests. This will help to make sure that the leaves of the cucumber plant do not turn yellow as there is no risk of the pests getting to the plant.

Final Thoughts

To conclude, there are several different reasons why the leaves of your cucumber plant have turned yellow and how you can fix them.

The leaves can be yellow due to a deficiency, disease, pests, lack of water, and lack of sunlight, but there are ways that you can fix these problems and have your cucumber plant looking healthy and back to normal.

There are some cases where the plant has become too diseased to be saved, so the only option is to remove the entire plant and the soil.

When this happens, removing just the yellow leaves will not fix the problem, so it is important to make sure that you remove the whole plant to prevent other plants from becoming infected.

Yellow leaves do not always mean that the plant is beyond saving, and there are solutions to help save your cucumber plant!