If you are wondering “Why are my cucumbers yellow?” your plants may be facing trouble. The yellowing of cucumbers is generally caused by improper watering, light stress, mineral deficiency, insect attack, and disease damage.

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Luckily, it is really simple to fix the discoloration. Stay till the end to learn all about the reasons and how to fix the problem without hassle.

Why Are Your Cucumbers Turning Yellow?

Your cucumbers turn yellow when you do not add water in adequate amounts. It can also happen when plants face nutrient deficiencies, disease attacks, and insect infestation. Similarly, poor lighting conditions can also cause the yellowing of cucumbers as well pollination problems.

– Inaccurate Watering

When you see cucumbers turning yellow, then chances are you are not applying water sufficiently. Water is critical for every plant as every physiological function depends on it.

So, when you let the soil stay dry for a long time, there will be no water for the cucumber plant. As a result, all the functions will be disrupted, and the plant will lose its colors with time. An under-watered plant usually turns yellow with poor fruit quality.

Underwatering is not the only crime you can commit with water. People often ask “Why are my cucumbers white?” The answer is adding more water than required. The cucumber is a plant that hates extra wet or moist soil. It is because the roots of the plants face air stress when there is water around them.

When the air or oxygen supply gets reduced, moisture and nutrient uptake will slow down. The decrease causes water and nutrient stress, and discoloration will occur.

Similarly, adding more water also causes fungal growth, giving a white-to-gray look. Moreover, water spots will appear if the water you have added is hard and some splashes fall on the cucumbers. It is a condition in which the water evaporates, and the lime will stay behind, forming white to yellow patches.

– Mineral Deficiencies

Why are my cucumbers yellow and round? If you are thinking about the cause, the answer is to apply more fertilizers. It’s no secret that nutrients or minerals are super important for plants.

They use it to make chlorophyll, a pigment responsible for giving green colors to the leaves. So, not adding fertilizers will cause a drop in chlorophyll, which will cause yellowing.

It is the nitrogen deficiency that hits the cucumbers the hardest. We all know that plants need nitrogen the most. This nutrient makes sure plants thrive and have shiny colors. It is also one of those nutrients that form chlorophyll. So, it is understandable why cucumbers become yellow when they don’t get nitrogen.

In addition, magnesium and iron deficiencies can also turn plants yellow. When there is magnesium deficiency, you will see yellowing near the vein, typically on the upper region. When plants lack iron, the whole leaf will turn yellow with greener veins.

– Improper Lighting Conditions

Cucumber plants need around six to eight hours of light to thrive and stay in true colors. If you grow them in locations with shade (by any material like a roof or nearby plants), then get ready to see yellowing cucumbers.

Cucumbers love warm days and direct sunlight. The plant “captures” this light and converts it into energy. This helps the plant to grow and maintain natural colors. But if there is light stress, plants will not produce energy. As a result, you will get small yellow cucumbers.

– Pollination Problems

Another reason that turns cucumber yellow is improper or no pollination. The flowers need to be properly pollinated to avoid any discoloration. If this doesn’t happen, the fruit will be misshapen and yellow.

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Pollination problems occur for several reasons, including the lack of pollinators and environmental factors. For example, if there are no beneficial insects in your garden, pollination might not occur as they take pollen from male flowers to female ones.

Similarly, any environmental factor (high temperature, cold stress, etc.) can stop pollen transfer, causing pollination failure.

– Disease Attack

Cucumber plants can also start having yellow patches due to several diseases. The common one is Cucumber Mosaic Virus (CMV), caused by aphids. This virus damages the cells and can also kill the tissues.

Furthermore, it also reduces chlorophyll within leaves, which also causes yellowing. When leaves become yellow, photosynthesis will not occur, which will also cause fruit discoloration.

Bacterial wilt is another cucumber disease caused by the bacterium Ralstonia solanacearum. In this, the water-taking vessels in the cucumber plants get damaged. As a result, the plants face water stress, and eventually, every part discolors.

In addition to bacterial disease, some fungal diseases also harm cucumbers. The main one is powdery mildew, which causes yellow patches on leaves, stems, and fruits.

When infected with this disease, there is also whitish-yellow powder-like spore growth on the plants. This causes light stress and a decline in photosynthesis. When this happens, the whole plant will turn yellow with time.

These are the main diseases that damage cucumbers. The worst part about them is that they can also infect cucumber seeds. If you sow such seeds, any plant sprouting from them will be of poor quality.

– Insect Infestation

When you see cucumber leaves turning yellow, chances are garden pests are damaging the plants. Cucumber beetles are the common ones you will see on them. This insect has yellow wings with black stripes and looks beautiful. But this beetle also feeds on every part and turns them yellow. It also spreads bacteria, which also causes yellowing.

In addition, aphids also feed on cucumber leaves. It sucks the chlorophyll-containing sap, which causes leaves to curl. When the plants face chlorophyll deficiency and curling, they will become yellow.

Furthermore, whiteflies also love to feast on cucumbers. They are also the main reason why plants get affected by mosaic viruses. Whiteflies also suck the sap, which directly influences the photosynthesis rate. This causes yellowing on leaves first, which can spread to other parts.

– Fruits Have Over-Matured

Harvesting cucumbers at the right time is important if you don’t want them to discolor. They usually get ripe after 50 to 70 days of planting. If you don’t “pluck” them out, the overripe cucumbers change their colors to yellow and orange.

They also keep growing bigger even if the harvest time has passed. But the problem is that no harvesting will allow any new fruit setting.

– Variety’s Response

Sometimes, the yellowing of cucumbers is no one’s fault. You might have chosen yellow cucumber varieties, and now the plants grown from them show their natural colors (yellow).

There are different yellow cucumbers, but the most popular is lemon cucumber. It has a small yellow fruit with some hints of greenness. Under this yellow skin, lemon cucumbers are white and taste mild. So, how to eat yellow cucumbers? Well, a cucumber salad is a good option.

But beware when it comes to the consumption of such cucumbers. Wondering are yellow cucumbers safe to eat? If the yellowing is caused by variety, they are safe for human consumption. If it is caused by over-maturing, diseases, or insect attacks, it is better to throw them away.

How Do You Stop Yellowing Cucumbers?

To stop yellowing cucumbers, you should give the plants proper water and nutrients. Letting them enjoy plenty of light for at least six hours is also critical. Furthermore, insect and disease damage can also cause discoloration of every plant part (including fruits).

– Add Water Accurately

When you see cucumber plants turning yellow, check how much moisture is in the soil. It would be best never to overwater or underwater plants to grow healthy cucumbers without complications.

Therefore, the best watering practice is to wait for the soil to dry out completely and then add water in controlled amounts. You should not sprinkle water on the plant leaves or fruits, or fungus will attack.

– Give Cucumbers Nitrogen-rich Fertilizers

To prevent yellow cucumbers, you should apply nitrogen fertilizer before the seed sowing. Adding such a fertilizer that contains other vital minerals, especially magnesium and iron, is also important.

You should apply fertilizers at the right time too. It is recommended to add small doses after every two weeks. Please apply at least one dose when the stem is growing and vegetative growth is at its peak. Then, ensure to add another dose right before flowering. Every dose should be nitrogen rich.

– Apply Insecticides

When you are growing cucumbers, you should keep a check on insect infestation. You can use organic repellents like neem oil, wood ash, sulfur powder, etc. You can also use beneficial insects, like ladybird beetles, mantis, net-winged, green lacewings, bees, etc. These insects kill harmful insects and can also help with pollination.

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If there are many pests in your garden and every second leaf has chewed parts, then go for chemical insecticides. They are fast acting and will kill all insects their fumes get in touch with. But the problem with them is that they also eliminate the beneficial insects. So, use them only if the insect attack goes out of hand.

– Protect From Diseases

Have your cucumbers turned yellow due to plant diseases? Then, it would be best if you started treatment immediately. In case of fungi or bacteria attack, use appropriate fungicides and bactericides. It is also important to dry the soil before you apply these treatments. It is because pathogens love damp soil and multiply quickly in it.

You should also keep the discolored fruits from growing more. So, what to do with yellow cucumbers? You should cut them or any other infected part and put them in a bag. Then, dispose of this bag far from your garden. You should also replace the soil with a well-drained one.

– Follow Best Growing Practices

If you have decided to grow cucumber plants, it is important to follow the best-growing practices right from the start. You should first select a well-lighted area, as cucumbers love light. Then, choose the perfect seed for sowing. You can either choose the yellow cucumber variety or a greener one.

Furthermore, follow the crop rotation. Grow cucumbers one season and then choose a plant for the next season with different pest problems. This will keep insect infestation, and even the disease spread, in check.

Moreover, during the whole growing process, keep the vegetable garden neat. It is because pathogens are present in dirt and pet feces. It would be best to eliminate any weeds you see, as they can also play their role in spreading insects and diseases. Doing these things will help you finally get your hands on green cucumbers.

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All-said, a lot of stress causes cucumbers to become yellow. But if you keep checking your plants regularly and follow the appropriate solutions discussed here, you can stop the discoloration. Check out the main takeaways to refresh every key detail discussed in this article:

  • Add water sufficiently to ensure plants do not have to deal with underwatering and overwatering complications.
  • Choose a spot where the light falls for at least six hours so that cucumbers maintain their colors.
  • Add fertilizers after every two weeks to avoid mineral deficiencies.
  • To stop insect attacks, use organic repellents, beneficial insects, and chemical insecticides.
  • When diseases start causing yellowing, prune off infected parts and apply appropriate treatments.

Stick to these points, and the cucumbers will stay in their natural colors.

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