Cucumber Plant Leaves Turning Yellow

It’s a vegetable that is loved by all and grows quickly with sun and water; cucumbers can proliferate as long as they receive consistent warmth and water.

Until or unless you are growing yellow cucumber, anyone planting green ones would love the cucumbers to be crisp and green and not turn yellow after a few weeks. If you wonder why your cucumber plant leaves turning yellow, you are at the right place.

Why Yellow Leaves on Cucumber Plants?

The leaves of the cucumber plants are large, broad, and bright green. But when you notice that the plant’s color is compromising, it’s a warning sign that the plant lacks nutrients or gets damaged by pests.

The damage caused by the aphids can lead to cucumber leaves turning yellow or wilting and curling. Another virus known as mosaic or mildew can also cause the yellowing of the cucumber leaves.

Deficiency of nutrients is prevalent in fruits and vegetables; lack of nitrogen, potassium phosphorous can cause the cucumber leaves to turn yellow. Other nutrients like magnesium, iron, and manganese can also cause the plants to have poor growth and turn the leaves yellow.

In this case, you will have to add nitrogen so that the plant is getting proper nutrients, but while putting nitrogen, make sure you are careful as an abundance of nitrogen can lead to the foliage’s overgrowth.

There will be little to no production of fruits. Nitrogen is one of those nutrients that deplete earliest as the soil can wash it away very easily.

Although adding nitrogen works and helps, many people add phosphorous and potassium to match the nitrogen levels, which doesn’t work. It is better to add a very small amount of nitrogen like compost; this will keep the levels in check and keep the yellow leaves at bay.

Also Read: Why Bitter Gourd Leaves Turning Yellow?

Why Cucumber Turning Yellow?

The yellowing of cucumber can be because of different or related issues. The cucumbers can turn small or misshapen because of the mosaic virus present in them. Bitter taste of the fruit is due to the presence of this virus. Yellow cucumbers can also be because of nitrogen deficiency.

If you are worried about why my cucumbers turn yellow on the vine, this could be because you have left the cucumbers on the vine for too long, which has resulted in the cucumbers having large and hard seeds and spongy texture.

This means that your cucumber is not going to be good for eating or pickling. Always pick your cucumber regularly because once they turn large, they aren’t usable. Lastly, not picking up cucumbers and allowing them to overgrow will only destroy the vine and not allow it to produce more fruit.

Let us take a deeper look at the issues that are causing your cucumbers to turn yellow. The reasons could be water level, pests, potassium disease, nitrogen, or iron deficiency; once you can find out why you can figure out how you can treat them.

Check the water levels

If you feel that the plants are not growing properly because of water levels, you can easily get rid of this problem using less water or more water.

You can also use handy gadgets to help you measure the moisture levels in your soil and prevent you from overwatering or underwatering. If you get this wrong step, chances of your leaves turning yellow are high.

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Keep a check on the light

Cucumbers love their sunlight. If your cucumber plants aren’t receiving the proper amount of sun rays, no matter how much water it or pour nutrients on it, the plant will just not grow.

Cucumbers need a 6-hour sunbath, and some versions also prefer 8 hours. Whether you are growing them under the sun’s artificial right, make sure that your plant receives the proper amount of sun rays.

Keep a check on the pests and disease

  • If you feel that your plants are fighting with pests, then try to determine what they are. The majority of the pests love to feed on cucumber plants. They are aphids, spiders, mites, whiteflies, leafhoppers, etc.
  • These pests are treatable, and you can treat them using insecticides, or you can also remove the plants’ damaged leaves. Treating the diseases on cucumber plants is a different game altogether. A very common issue, the mosaic virus and the verticillium wilt usually spread by pests. They can be found under the soil and Can be a result of the previous crops.
  • Unfortunately, you can’t treat these two diseases. You will only have to remove the infected plants as soon as you can.
  • On the other hand, some diseases are easier to treat. If you notice that your plant has white powdery spots or white coating, this means that your plant has a fungal spore. You can treat these infected leaves by picking them off. This issue can also be solved by overwatering.
  • The yellow and brown spots on the plant indicate the downy mildew. For this, you will have to improve the air circulation and keep your garden free of debris.

Also Read: How to Save Tulsi Plant from Dying?

Nutrients Deficiency

Each deficiency can be treated in its way, but for this, you will have to determine which deficiency is making the leaves of your plant turn yellow. Here is an explanatory breakdown of the common deficiency.

The deficiency of nitrogen can be easily cured using a soil fertilizer with a proper dilution rate. Even if there is a tiny mishap, your whole lot of cucumber plants can damage. Always use organic fertilizer.

Potassium Deficiency

The deficiency of potassium is caused by the excess of calcium, sodium, or nitrogen.. so feed your plants with organic nutrients that are perfect for the plants and always feed the plants at the growth stage. When your plant is flowering, it will require an extra amount of potassium.

Iron deficiency

In case of iron deficiency in the plant, treat the plant, or treat the soil. Doing both will be a bonus, but always try to maintain a balance. You can also spray liquid iron on the plant foliage. Though this isn’t a lasting solution, it will work. For treating the soil, you can use powdered or granular chelates iron. You will have to sprinkle this around the roots are.

Steps you need to follow to have a fruitful cucumber harvesting

Start by making successive planting every two weeks, so that you can have continued harvest. If the soil is warm, the cucumbers will grow quickly and ripe in about six weeks.

When should you plant cucumbers?

The cucumber plants should be seeded no earlier than two weeks after the last frost date. These plants are extremely susceptible to forming and cold damage. The perfect soil must be at least 70-degree Fahrenheit for germination.

To have a good head start by sowing seeds indoors for about three weeks before you begin to plant them in the ground. These plants like bottom heat, you can use a heat mat.

Always Space the Cucumbers

  • Start by choosing and preparing a planting site.
  • Always choose the place that has full sun, as cucumbers need lots of warmth and light.
  • Cucumbers also require fertile soil. Start by mixing compost in aged manure before planting the seeds in a depth of 2 inches; they proceed onto work into the soil for about 6 to 8 inches deeps.
  • Keep in mind that the soil should be moist and drained and not soggy and compacted.
  • Keep in mind that the soil should either be neutral or slightly acidic that is between 6.5 to 7.0
  • You can also improve the clay soil by adding organic matter. You can add peat compost, even rotten manure. Even light and sandy soils are perfect for as they warm quickly in the spring and summer season.

How do I plant cucumbers?

Start by planting the seeds 1-inch deeps into the soil. The plants should be distant from each other at 2 to 3 feet. If you are planting a trained trellis, space the plants around 1 foot apart.

You can also plant the cucumbers in a mound, they should be spaced at around 1 to 2 feet apart, and you need to plant 2 to 2 seeds in one mound. Once you have seen that the plants have reached a height of 4 inches apart, then thin the plants to one plant per mound.

If you stay in cooler regions, you can warm the soil by covering the hill or the row with black plastic.  Once you are done planting, start by mulching the area with a straw, chopped leaves, and other organic mulch, keeping all the pests at bay. You can also keep the bushes type of plants on the ground to avoid any of the diseases.


If you’ve minimal space, making your own trellis is a good idea, when you want the vine to climb. The trellising process will also protect the fruit from damage, especially if they are lying on a mist ground.

It’s recommended to cover the freshly planted cucumber seeds with a net or a berry basket. This will keep them away from predators in the garden and avoid them to dig out the seeds.

Care you need to give to your cucumbers

One main care that you need to give to your cucumbers is watering. Cucumbers require around 1 inch of water every week, and if the temperatures are high, you need to pour in more water. Start by putting your finger in the soil; if you feel that your finger has passed it dryly, add more water. If the water is inconsistent, then the fruit will taste bitter.

Always water the plant slowly and in early morning or afternoon. Try to avoid the leaves as this will encourage the leaf diseases and can ultimately ruin the plant. If you can try to water the cucumbers with a soaker hose or drip irrigation, this way, the foliage will stay dry.

Always mulch so that the soil can retain moisture.

When you notice that the seedlings have emerged, start watering the plant frequently and then increase the amount to a gallon per week after the fruit has formed.

When the seedlings have reached a height of 4 inches, start thinning out the plants to be 11/2 feet part. If you have poured organic matter into the soil, you will have to side-dress your plants with the compost or well-rotted manure.

Use a Liquid Fertilizer

You can also use a liquid fertilizer, a liquid fertilizer that has low nitrogen and high potassium phosphorus formula is the best.

Start by applying one week after bloom, and then after every three weeks, it should be applied directly into the soil around the plants. You can also use a granular fertilizer in the soil. Remember that you aren’t over-fertilizing as the chances are the fruits fill get a stunted growth.


Keep these tips in mind, and you will have proper growth. Cucumbers can attract a lot of issues if they aren’t provided proper care. Water them, feed them properly, cover them, and prune them regularly, and you will have the best harvest! Understandably, being a plant parent is tough, and you have to face so many issues daily. But if you proceed calmly and slowly, you will be able to overcome them all.

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