What To Do For Yellow Leaves On Cucumber Plants In A Container

There are many reasons why the leaves on your cucumber plant could be turning yellow. Your plant could be overwatered or underwatered, it could have a disease or fungus, or it could have a pest problem. It is important to know why the plant’s leaves are turning yellow and how to address the problem. 

Why Are The Leaves On Your Cucumber Plant Turning Yellow, And How Do I Fix It?

Too Much Water

Cucumber plants need about 1-2 inches of water per week, depending on what cycle of life they are in. If you are giving your cucumber plant too much water, the roots will not be able to get the necessary oxygen needed to survive. 

How Do I Fix This?

The first thing you should check for is to make sure there is a drainage hole at the bottom of the pot your cucumber plant is in. If there is no drainage hole, the water will pool at the bottom of the pot, and your plant will drown. 

If your pot has a drainage hole, you should then try to loosen the soil. If your soil has become too compact, it can cause drainage problems. Try adding some loose sand to the soil to help drain water a little fast. 

If the roots of your cucumber plant are beginning to turn brown, the last thing to try is to replace the soil. If you let water sit in the soil, the roots can’t breathe, and the mold and mildew can begin to grow. This is called root rot. 

If you can catch the draining problems early enough, you might be able to save the plant by replacing the soil. Try adding a drainage medium, such as sand or vermiculite, to help your plant drain easier.

Pesky Pests

Pests are very common on plants, especially sap-sucking pests. If the leaves of your cucumber plant are turning yellow, it’s possible you have a bug problem. Some of the most common bugs found on cucumber plants include aphids, spider mites, whiteflies, and the potato leafhopper.  

Aphids are easy to identify, as they are the only pest green in color. Aphids like to hide, so if you suspect you have them, you should check on the underside of leaves and directly against the stem of the plant. They will also leave behind a sticky residue called honeydew that is easily identifiable.  

Spider mites are a little harder to see. In fact, you will probably see their webs before you see the spiders themselves. Spider mites also like to stay hidden underneath the leaves of plants. 

You will know your cucumber plant is infested with whiteflies when you see a cloud of white insects fly away after a leaf is shaken. Like aphids, whiteflies will also leave a sticky residue behind called honeydew. 

The last pest you might find on your cucumber plant is called the potato leafhopper. This insect is larger than the ones listed above, but it still enjoys sucking the sap out of plant leaves. 

How Do I Get Rid Of The Pests On My Cucumber Plant?

The most important thing to remember when treating your cucumber plant for bugs is to make sure you are using an organic product. Whatever gets sprayed on your plant will be ingested by you when you go to eat the fruit, so it is important to use a safe product. 

One product you can use to help get rid of pests on your cucumber plant is Neem Oil. Neem Oil is an ingredient found in facewash, which tells us it is safe. 

You can find Neem Oil in pest control products at hardware stores or plant nurseries. You will want to use this product either very early in the morning or late at night. 

Neem Oil is oil. Therefore, if there is oil still present on the leaf when the hot sun is beating down on the plant, the oil can cause more harm than good. By spraying the oil in the morning or at night, you can ensure the leaf will have enough time to dry before the sun comes up. 

Plant Disease

Another reason why your cucumber leaves might be turning yellow is due to the presence of a disease or fungus. A few diseases specific to cucumber plants include Cucumber Mosaic Virus, Fusarium Wilt, and Downy Mildew. 

If you see yellow leaves that are beginning to crinkle and curve downward, your plant could have Cucumber Mosaic Virus. This disease is so serious, that it can stay in the soil until the following year, infecting your new plants. 

You will Fusarium Wilt, or Verticulum Wilt, in the older leaves of your cucumber plant first. The edges will start to turn yellow and will spread inward. This disease is spread from cucumber beetle larvae that feed on the plant’s roots. 

Of all the diseases listed above, downy mildew is the mildest one. The upper surfaces of the plant’s leaves will begin to turn yellow and then brown. You will also be able to see gray fuzzy spots on the undersides of the leaves. 

How Do I Manage My Cucumber Plant’s Disease?

How you treat your cucumber plant’s disease will depend on what it is plagued with. 

Unfortunately, if your cucumber plant has Cucumber Mosaic Virus or Fusarium Wilt, the only solution is to get rid of the infected plant. It is also advised to replace the soil in the area as well, as those diseases can affect next year’s plants if they are still present in the soil. 

Downy Mildew is treatable. There are cucumber varieties that are more resistant to this disease than others, so choosing the right variety will help significantly. 

The first thing you can do if you suspect your cucumber plant has Downy Mildew is to trim it up to ensure air can circulate around the plant. Prune any small stems that are crowding the plant, as well as any dying stems. Pull back some of the soil around the base of the stem to make sure the plant can breathe. 

The second step would be to dig up and dispose of any infected plants that are beyond saving. This will help give your healthy plants a fighting chance. 

There are also organic fungicides you can use to help prevent and treat this disease. Copper is a great organic fungicide that should be used either early in the morning or late at night. It is important to monitor your plants to catch these diseases before they are too out of control. 

Nutritional Deficiency

Like humans, plants need a variety of nutrients in order to grow up healthy and strong. Some of the vitamins cucumber plants need are nitrogen, phosphorous, and potassium. Without the proper amount of nutrients, your plant will turn yellow and eventually die. 

If your cucumber plant is suffering from a nitrogen deficiency, the older leaves on the plant will turn yellow first, while the new growth will continue to look green and healthy. 

Cucumber plants need a lot of potassium. If the tips of your plant’s leaves are beginning to turn yellow, your plant may be lacking potassium. New growth will be small and dull-looking, and the fruit of the cucumber plant can grow narrowly at the stem of the plant, making it look like a club. 

Iron is also important to a cucumber plant. If your plant is lacking iron, the new leaves that grow will be yellow, while the veins of the plant will stay green. 

If your cucumber plant is suffering from a zinc deficiency, the leaves of the plants will be small, and the older leaves will turn yellow. 

How Do I Give My Cucumber Plant More Nutrients?

If your cucumber leaves are turning yellow due to nutrient deficiencies, the solution is to feed them with an organic fertilizer. 

There are two different ways you can feed your cucumber plant more nitrogen. 

The first way is by adding a 2-inch layer of compost to the soil where your plant is located. The other fix for a nitrogen deficient plant is to add a few teaspoons of a 6-10-10 fertilizer. 

Extra iron can be given to your cucumber plant in two different forms. The first is a granular or powder iron additive that you will sprinkle into the soil before watering in. The other form is a liquid iron that can be sprayed on the plant and in the soil. 

You can help give your cucumber plant a potassium boost by feeding it with a fertilizer that has a higher middle number in the #-#-# sequence. You can also treat the soil if it is too acidic or alkaline. 

There are two different products you can give your plant that will give it more zinc. The first product is a zinc sulfate solution that you can spray directly onto the plant. The other solution is organic kelp. 

All of the products listed above to help your nutrient deficient plant are organic products that are safe for you to consume. Be sure to read labels before applying anything to your plant!

Should I Cut Off The Yellow Leaves Of My Cucumber Plant?

Yes, you should trim off the yellow leaves you see on your cucumber plant. There are a few reasons why you should cut off these yellow leaves. 

If the yellow leaves are caused by a disease, you run the risk of allowing the diease to spread throughout the entire plant. Fewer leaves will also allow the air to circulate properly. 

You should also cut off the yellow leaves of your cucumber plant because of how wild the vines of the plant can grow. By pruning the yellow leaves on your plant, you will not only allow it to stay healthy, but you can keep the growth under control. 

It is important to cut off yellow leaves as you see them on your cucumber plant to ensure it stays healthy!

How Do I Keep My Cucumber Plant’s Leaves From Turning Yellow When It Is In A Container?

You can keep your cucumber plant looking healthy and green by feeding it necessary nutrients, keeping up with pruning, and spraying preventativly for bugs and diseases. You also want to make sure the proper tools are used when potting your plant. 

Feed Your Cucumber Plant The Necessary Nutrients

In order to ensure your plant stays green, you should feed it with an organic fertilizer regularly. Be sure to read the label on the fertilizer to make sure you don’t over feed it. 

Prune Your Plant Regularly

It is important to keep up with pruning your cucumber plant so air can properly circulate around the stem and leaves. If air cannot properly flow, mold and mildew can build up on and around the plant. 

You should also cut off yellow leaves as you see them to ensure the diease does not spread from one plant to the next. 

Spray Regularly For Pests

Fruit is sweet, so bugs will be attracted to it. It is important to preventatively spray your cucumber plant to ensure it stays bug-free!

Use The Proper Tools When Planting

There are two important tools you will need when planting a cucumber plant in a container. The first is to make sure the container has a hole at the bottom to allow for proper drainage. The second important tool is a soil that will drain well enough for the plant. 

Can The Yellow Leaves On My Cucumber Plant Turn Back To Green?

When you see a leaf turning yellow, that leaf is dying and there is no way to make that yellow leaf green again. It is important to make sure you cut off any yellow leaves so the problem causing the yellow leaf does not spread to the entire plant. 


It is important to stay on top of the health of your cucumber plant. You can do this by cutting off any yellow leaves you see, spraying preventatively for bugs and disease, feeding your plant with vitamins and nutrients regularly, and using the proper tools when potting your plant. If you follow these guidlines, you will have fresh cucumbers for your table in no time!

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