What causes cucumber leaves to turn yellow?

In this brief guide, we will answer the question, “What causes cucumber leaves to turn yellow?”. We will further elaborate on the reasons that could turn the cucumber leaves yellow, and how we can prevent this.

What causes cucumber leaves to turn yellow?

Cucumber leaves can turn yellow because of:

  • Deficiencies in the soil
  • bacterial and fungal diseases
  • Watering
  • Inappropriate sunlight
  • Pests that may include spider mites, aphids, whiteflies and potato leafhopper

What are the main culprits behind the yellowing of cucumber leaves?

If cucumber leaves are turning yellow on your cucumber plant, don’t get worried. It is one of the common gardening problems. The major reasons, why they are turning yellow are described below:

Deficiencies in the soil

Nutrient balance in the soil is essential for both vegetables and fruits.

It is recommended to conduct a soil test. By testing your soil you will come to know about the depleted ingredients in the soil which you can then easily add to the soil.

Nitrogen Deficiency

Nitrogen is a major requirement for the survival and growth of cucumber leaves. Yellowing of cucumber leaves mainly occurs due to the deficiency of nitrogen in leaves. Excessive lack of nitrogen could also lead to the death of plants.

Nitrogen is a responsible factor in the foliage and the growth of plants. It makes the leaves look healthy.

So, how to fix nitrogen deficiency in plants? The easiest way is by the addition of a few tablespoons of fertilizer. You must follow the instructions which are usually mentioned on the packet and add fertilizer in a ratio of 5-10-10, otherwise, excessive fertilizer can damage your plant and the cucumber plant will not produce more cucumbers. 

In addition, ammonium nitrate could be added to the soil when the cucumber plants start flowering. Add only a tablespoon of ammonium nitrate and repeat this cycle after 3 weeks.

You can also try adding a thin layer of compost around the soil of the plant.

All these solutions will help the growth of leaves if they are becoming yellow due to nitrogen deficiency.

Potassium deficiency

The cucumber plant requires a large amount of potassium when it begins to produce flowers. One of the significant symptoms that will indicate the deficiency of potassium is the yellowing of leaves from the tips and edges of leaves.

To overcome this problem you should apply a fertilizer that has a good balance of potassium. Further, you can give a thin layer of compost around the soil of the plant which will also help to reduce potassium deficiency and ultimately will lower the yellowing of leaves.

Iron Deficiency

Iron deficiency could also be a reason behind the yellowing of cucumber leaves. A visible sign of iron deficiency in cucumber plants is that the leaves become yellow but the veins still remain green in color.

You can overcome this issue either by spraying the foliage with the help of liquid iron on the cucumber plant or by spreading the granules of iron surrounding the roots of the cucumber plant.

Zinc deficiency 

Zinc deficiency can cause cucumber leaves to become yellow and drooping. It also makes the leaves very small. Furthermore, it inhibits the growth of the cucumber plant.

The easiest method to tackle the situation is by spraying zinc sulfate solution or organic kelp.

Water Levels

It is necessary to give the cucumber plants the right quantity of water. Overwatering or underwatering can damage the plants.

Overwatering can result in a deficiency of oxygen in roots, making the cucumber leaves become yellow and wilted.

Inadequate water can also cause the leaves to turn yellow. The plant only requires 1-2 inches of water each week.

Plant diseases

Some serious plant diseases could also occur due to these deficiencies which can also lead to the death of the plant after yellowing the leaves.

Some of these diseases are described below:

  • Cucumber mosaic virus
  • Fusarium wilt
  • Downy mildew

Cucumber mosaic virus

The indication of cucumber mosaic virus is mottling, fern leaf distortion, slight patterns of mosaic, and flecking. The cucumber mosaic virus spreads through aphids and takes no time in spreading. 

If one cucumber plant is infected then in a very few hours, a large number of surrounding plants could also get affected by the cucumber mosaic virus.

Fusarium wilt

Fusarium wilt is due to a fungus named Fusarium oxysporum which could survive for a long time in the soil in the form of spore’s termed chlamydospores or in connection with plant debris.

Downy mildew

Downy mildew is a pathogen caused by Pseudoperonospora cubensis.  It survives in wetter climates. 

It is indicated by yellow marks that form on the surface of cucumber leaves and that ultimately cause the Other FAQs about Cucumber that you may be interested in.whole leaves to become brown. 

Other FAQs about Cucumber that you may be interested in.

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In this brief guide, we have provided an answer to the question, “What causes cucumber leaves to turn yellow?”. We have further elaborated on the reasons that could turn the cucumber leaves yellow, and how we can prevent this.



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