Cucumber Plants Dying From Bottom Up: 7 Causes & What You Can Do

Cucumber plants suffer from a number of problems that can kill the plant.

Nutrient deficiencies, lack of watering, slow-draining soils, plant diseases, and temperature variations are all sometimes responsible.

If you find your cucumber plants dying from bottom up, then it’s essential to quickly identify the problem and take action. Sometimes, the plant can be saved.

So in this article, we’ll show you how to identify the cause, and what you can do about it.

Why Are My Cucumber Plants Dying From Bottom Up?

cucumber plants

Nutrient Deficiency

A lack of either magnesium or nitrogen in the soil creates a deficiency in cucumber plants with tell-tale symptoms.

Because these deficiencies first affect the older leaves, you’ll notice your cucumber plants dying from bottom up. If the deficiency continues, it will move up the plant to the younger leaves as well.

Because these nutrients are involved in the production of chlorophyll, the first sign of the problem is a yellowing of the cucumber leaves. A process known as chlorosis.

Plant growth is negatively affected. And the leaves start to die and fall off if the condition is allowed to progress.

To identify the problem, look closer at the leaves. If the veins are still green while the area in between is losing its color then it’s most likely a lack of magnesium.

Whereas a lack of nitrogen causes yellowing of the leaves that spreads from the inside to the outer edges, also spreading to the veins. The stems of the plant turn purple or reddish.

Consider adding nutrients to the soil so your cucumber plants get the essential building blocks they need.

But be careful when adding fertilizer. Too much potassium and ammonium can reduce the amount of magnesium in the soil.

High nitrogen fertilizer will help if nitrogen deficiency is the problem.

And you can try using Epsom salt for cucumber plants to correct a magnesium deficiency.


Watering can prepared to water cucumber plants

When the conditions are right, cucumber plants grow quickly. But to do that, they need a lot of water.

You should make sure they’re getting at least 1-2 inches per week.

When they lack water, their leaves start to wilt, particularly in the sunlight. If the drought continues, they start to turn brown and die.

They only need watering 1-2 times per week. Check the top inch of soil with your fingers. When it feels dry it’s time to water your plants again.


The type of soil your cucumbers are planted in is important because it affects water drainage.

They prefer to grow in a loose, light, slightly-acidic, fast-draining soil.

Heavy clay soil that drains poorly is often soggy for extended periods. This stops the roots from absorbing enough oxygen from the soil. And will lead to cucumber plants wilting.

A lack of organic matter in the soil also leads to drainage problems. So one of the ways you can improve soil permeability in heavy soils is by digging in compost. This keeps the soil evenly moist for longer, allowing the easy transfer of nutrients to plant roots.

If your soil dries very quickly, applying a 1-inch thick layer of mulch on top is a good way to slow evaporation and keep it moist for longer.


Cucumber plant health is affected by temperature. At less than 50°F the leaves will start to wilt and turn brown

Soil temperatures of 62°F and under will also have a negative effect. Even just a quick overnight drop to below 60°F can be noticeable.

So it’s a good idea not to plant your cucumbers outside before temperatures warm.

If you’re moving your plant outside after starting the seedlings indoors, then make sure to harden them off for a couple of weeks so they get used to the change in conditions.

Plant Diseases

Is a disease responsible for your cucumber plants dying from bottom up?

These are 3 of the most common you should check for:

Bacterial Wilt

Cucumber beetle

Cucumber plants become infected with bacterial wilt when cucumber beetles feed on their leaves.

They chew on the underside, leaving the upper surface intact, but eating away at the insides. In the process, they transfer the bacteria from their stomach.

The first symptoms are leaves turning a dull green and wilting during the day. But recovering during the night.

As the infection progresses the foliage turns yellow and eventually brown. Death follows after a short time with the cucumbers perishing on the vine.

Look to see if you can find the bugs. They’re easy to identify as they’re bright yellow with black striped or spotted markings.

Unfortunately, there isn’t an effective treatment. And infected plants need to be removed from your garden and destroyed, or buried in the ground. So it’s important to prevent the beetles to stop this bacterial infection from spreading.

Removing weeds from your garden and spreading a layer of mulch around your plants reduces egg-laying.

Using a floating row cover will prevent the beetles from getting to your plants. But remember to remove it when it’s time for the cucumbers to flower.

Phytophthora Blight

Phytophthora leaf blight

Phytophthora blight of a Taro leaf

Phytophthora blight is a fungal infection that’s more commonly seen on squash plants and pumpkins. But it also causes difficulties for cucumbers.

Early symptoms include irregular shaped brown spots developing on the leaves along with wilting. But the infection will spread to all parts of your plant and cause its complete collapse.

The plants lose their roots and become easy to pull out of the ground. And close inspection will reveal a white fungal growth on the cukes, which also become soft and puncture easily.

This infection spreads through water and is most common in soil that drains poorly.

You’ll need to remove and destroy infected plants and fruit. Using a fungicide can help to prevent this fungus, but it won’t save infected plants.

Fusarium Wilt

Fusarium wilt tobacco plant

Fusarium wilt of a tobacco plant R.J. Reynolds Tobacco Company Slide Set, CC BY 3.0

It’s more common to find fusarium wilt affecting tomato plants in your vegetable garden. But it can spread to cucumbers if you’re growing them nearby.

Insects, contaminated water, and garden tools all help transfer it between plants. And unlike most fungal diseases, it thrives in hot and dry conditions.

The leaves of your plants will appear dry and start turning yellow and brown. The older leaves lower on the plant are affected first before newer ones.

To treat it, first remove the infected parts of your plant. Then try using a fungicide in the root zone, such as Mycostop.

You can also get fusarium wilt resistant varieties of cucumber.

Insects & Pests

A number of insects feed on cucumber plants and can cause the plant to die. Common examples include the squash bug, squash vine borer, aphids,spider mites, and the cucumber beetles mentioned above.

Inspecting your plants regularly will reveal their presence so you can take appropriate action to protect them.

Handpicking can keep the numbers down. But it may take insecticides to completely get rid of an infestation.

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