7 Reasons Your Cucumber Leaves Are Turning Yellow - Backyard Boss
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7 Reasons Your Cucumber Leaves Are Turning Yellow

Have you been growing cucumbers in your garden and noticed that the leaves are starting to turn yellow? Don’t worry, this guide has got you covered! If your cucumber plants have started to produce yellow leaves, it’s important to figure out the cause so you can take steps to remedy the problem. Read on to find out what might be causing your cucumber leaves to turn yellow, and how to fix it!

Lack of Nitrogen

yellow cucumber leaves
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Yellowing cucumber leaves could be a sign of a nitrogen deficiency. Nitrogen is an essential nutrient for plants, and it helps to promote growth and green foliage. If your cucumber plants are lacking in nitrogen, they may start to yellow and eventually die.

There are a few things you can do to prevent or cure a nitrogen deficiency in your cucumber plants. Make sure you are fertilizing them regularly with a balanced fertilizer that contains nitrogen. You can also add compost or other organic matter to the soil to help improve its nitrogen content.

Lack of Water

Watering green cucumber plant.
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If your cucumber leaves are turning yellow, it may be due to a lack of water. Cucumbers are 95 percent water, so they need a lot of hydration to stay healthy. A lack of water can cause the leaves to turn yellow and eventually die.

If you see your cucumber leaves turning yellow, make sure to immediately check whether your soil is dry. Cucumbers like soil that is moist, but not sopping wet. If the soil is dry, make sure to water them immediately. Try to give them a deep watering at least once a week. If the problem persists, you may need to consult with a gardening expert.

Excess Water

watering vegetable garden
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Excess water can lead to several problems for cucumber plants, including yellowing leaves and nutrient deficiencies. Overwatering can also cause root rot, which can kill the plant. Yellowing leaves are an early sign of root rot. White powdery mildew on the leaves of your plant is another sign you might be overwatering your cucumbers (more on powdery mildew later).

If you notice that your soil is very wet or that there is a pool of water around cucumber plants, that may be why their leaves are yellowing. There are a few things you can do to help them recover.

First, make sure you are watering your cucumber plants properly. Water them deeply but less often to encourage deep root growth. And be sure to water the base of the plant, not the leaves. Wet leaves can promote fungal diseases.

Additionally, fertilize your cucumber plants with a balanced fertilizer that includes nitrogen, phosphorus, and potassium.

Lack of Sunlight

Sunlight on baby cucumber plants
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If your cucumber plants are looking a bit lackluster, it might be due to a lack of sunlight. Cucumbers need at least six hours of direct sun per day to thrive. If they’re not getting enough light, their leaves may turn yellow, and they can stop producing fruit.

To get your cucumber plants back on track, move them to a sunny spot and make sure they’re getting at least six hours of direct sun per day. If you can’t provide that much sun, you may need to supplement with artificial light. Try using grow lights or fluorescent bulbs placed about 12 inches above the plant canopy.

Excess Heat

Sunburned cucumber leaves
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Cucumbers are a warm-weather crop and require temperatures between 75 to 85 degrees Fahrenheit to thrive. When temperatures exceed this range, cucumbers will suffer from heat stress, which can cause leaf drop and sunburn.

There are several ways to combat this issue. First, make sure your cucumbers are getting enough water. They should be watered deeply and evenly, especially during hot weather. Mulching around the plants can also help retain moisture and keep the roots cooler.

If possible, provide some shade for your cucumbers during the hottest part of the day. A simple way to do this is to place a piece of cloth or burlap over the plants. Just be sure to remove the cloth during cooler hours so the cucumbers can get enough sunlight.

Pest Infestation

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If you see cucumber leaves turning yellow, it is important to inspect the plant for pests. Aphids, cucumber beetles, whiteflies, and spider mites are all common cucumber pests. They suck the sap out of the plants, which can lead to nutrient deficiencies and eventually death.

The best way to control pests is to prevent them from getting into your garden in the first place. Keep your garden neat and free of debris where insects can hide. Inspect plants regularly for signs of pest damage. If you do find pests, there are many organic and chemical pesticides that can be used to eliminate them.


Powdery Mildew on a tomato plant
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If your cucumber leaves are turning yellow, it could be a sign of disease, such as downy mildew, and powdery mildew. Both of these diseases can cause the leaves of your cucumber plant to turn yellow and eventually die.

If you think your cucumber plants are infected with either of these diseases, there are a few home remedies to try, but it may be best to contact a professional. They will be able to tell you the best way to treat these diseases and prevent them from spreading, as they can do so quickly and cause serious damage.

Don’t Wait

Have you ever had a problem with your cucumber leaves turning yellow? If so, you’re not alone. A lot of gardeners have this issue from time to time. The good news is that there are usually easy solutions to the problem, and this guide has outlined some of the most common causes — and how to remedy them.

Do you have any tips or tricks that have worked for you? Drop them down in the comments below!