Squash Plants Turning Yellow is a serious problem caused by drought stress, overly moist soil, improper lighting conditions, insect attacks, and diseases.

Squash Plants Turning Yellow

Thankfully, you can fix these leaves and enjoy top-quality fruits easily by applying adequate water and taking care of lighting among others.

So, if you want to know everything about the reasons that cause yellow leaves and what to do to fix them, then stick with us to the end.

What Are the Reasons Behind Squash Plants Turning Yellow?

The reasons behind squash plants turning yellow are usually water stress, incorrect lighting, insect infestation, and poor soil conditions. Furthermore, fungal and bacterial diseases also impact leaves’ color and turn them yellow. Such leaves fall off, and plants don’t look aesthetically pleasing.

– Applying Insufficient Water

Squash plants need adequate water for proper growth. They need it to perform critical physiological functions within the body. Furthermore, water is also crucial for the transport of nutrients from the soil to other parts of the plants. So when you add this necessity in low amounts, these functions will take place slowly. Since leaves are the main site of photosynthesis, they will show the first sign of trouble by becoming yellow.

– Overly-moist Soil

Adding lots of water is not a smart move either. When the soil gets extra moist, aeration around the roots is affected. This causes oxygen stress, which leads to root complications/diseases, ultimately causing leaves to turn yellow.

Also, overwatered squash leaves invite different diseases and insect attacks. Therefore, it is super important you add an adequate amount of water, which should be sufficient for plants to grow normally.

– Nutrient Deficiencies

No plant likes to be nutrient deficient. It is because every plant needs minerals for cell growth and overall health. Out of all nutrients, nitrogen deficiency hits plants the most. It is because this mineral helps plants to attain green foliage and have seamless vegetative growth. So, when it is unavailable, get ready to see some yellow leaves on squash plants.

In addition, iron deficiency also causes leaves to turn yellow. We all know that it is chlorophyll that gives leaves their green color. But when there isn’t any iron for plants, they won’t be able to produce chlorophyll. When this happens, photosynthesis will also be affected, and plants will then have a shortage of food and energy. Due to this, you will eventually see leaves becoming yellow and dying. Therefore, it is critical soil contains both macro and micro nutrients for plant health.

Squash Plants Turning Yellow Reasons

– Imbalance of pH

When growing squash, you should also consider the soil’s pH. The optimal range for a squash plant is around 6.5 to 7.0, which means it loves slightly acidic to neutral soil. If it is not in this range, then nutrient uptake won’t happen, no matter how many fertilizers you apply. As a result, plants will become nutrient deficient, and leaves will turn yellow.

– Fungal and Bacterial Diseases

Fungal and bacterial diseases can also be behind the Squash plant’s yellow leaves. Generally, it is the root rot that causes the most trouble. It occurs when you overwater plants more than required. In this, roots start to rot, which leads to poor performance and, ultimately, leaf complications. When leaves turn yellow, they wilt and die.

Fusarium wilt is a fungal disease that greatly impacts plants. Fusarium oxysporum fungus is behind it, which mainly affects the roots. You already know that damaged roots cannot absorb water and minerals necessary for plant growth. So there will eventually be yellowing of leaves in this disease as well.

Bacterial wilt is another squash disease that is caused by soil-borne bacteria. In this, the tips first start to discolor and wilt. After some time, the whole leaf will change to yellow and fall off.

Downy mildew is another plant’s enemy. In this, you will notice squash leaves turning yellow with brown spots. It is because this fungal disease causes both yellow and brown lesions, which greatly impacts photosynthesis. The worst part about this fungal disease is that it can also attack other plants in your garden (especially cucumber, melon, and zucchini plants).

– Insect Infestation

Insects like squash vine borers, squash bugs, spider mites, aphids, etc., also love to feast on a Squash plant, which leads to yellowing leaves. They suck the sap, which causes dots to appear. When lots of them start to feed, leaves start to change their color to yellow and can also drop off.

That’s not it. Aphids can also cause the spread of the cucumber mosaic virus. In this disease, the cupping starts from the middle vein, and the whole leaf gets filled with yellow spots. This virus also damages the fruit, which will make it inconsumable.

– Sunburn

Too much sun or overexposure to grow light can also lead to leaves having big yellow patches. It is because leaf cells can only tolerate light intensity to a limit. If it exceeds, then sunburn will occur. In this, cells start to die, and those remaining cannot absorb light for photosynthesis. As a result, plant leaves will turn brittle. If you don’t do anything, you will also notice yellow squash leaves turning white.

– Lack of Sun/Light

If you put plants in the shade for fear of sunburn, another problem will occur: squash plant leaves turning brown. It is because since light is crucial for plants to generate their food via photosynthesis, putting them away from it can lead to energy shortage. After some time, these leaves will become yellow and die. So, what can you do to treat the yellowing of leaves? Let’s find out.

How to Fix Squash Plants Turning Yellow?

To fix squash plants that are yellow, you should add water sufficiently, put the pots in perfect spots, apply insecticides, balance the pH of the soil, and cut off infected parts. After applying these treatments, you should keep your garden neat and tidy to avoid further complications.

– Apply Adequate Water

When you see yellow leaves, the first thing to do is ensure that moisture is adequate in the soil. It is because both overwatering and drought can lead to yellowing. You should apply two to four inches of water above the soil at least once every week.

– Take Care of Lighting

Squash needs around six hours of sunlight every day for proper growth. However, more than eight hours of it can cause trouble. So, make sure you choose the right location if you are growing them outdoors.

You will have to do two things if you are an indoor gardener. First, keep plants safe from the lights to avoid sunburn. Then, ensure they receive six hours of light for smooth growth and to avoid complications.

Squash Plants Turning Yellow Solutions

– Add Nutrients When Needed

To avoid nutrient deficiency, add organic and commercial fertilizers at the right time. Apply them in at least three stages to protect leaf health and to have better fruit quality:

  • Before seed sowing
  • After seedling emergence
  • Before flowering

However, if the soil pH is in the ideal range (6.5-7.0), applying nutrients will be beneficial. To be sure, use pH strips as they are cheap and simple. Experts also suggest gardeners own a pH meter.

If the pH is lower than 6.5, then you will have to apply basic compounds, like dolomite lime, wood ash, baking soda, crushed egg shells, etc., to increase it. If you get a reading of more than 7.0, add acidic compounds like sulfur, peat moss, etc.

– Get Rid of Unwanted Insects

First, give natural insecticides a try to protect squash plants from insects. Use neem oil spray, cayenne pepper spray, insecticidal soap, diatomaceous earth, etc. It is because these are inexpensive and do not harm the environment. If they don’t get rid of every insect, then go for commercial insecticides. These are costly, and you should carefully follow the dosage instructions on the label before applying them.

– Treat Diseases

To deal with diseases, you should first cut off infected parts and clean the garden of debris. Then, apply fungicide or bactericide to curb the disease effect. After this, you should water plants sufficiently and make a habit of cleaning the surroundings frequently.

Conclusion of Squash Plants Turning Yellow


So, that’s all about what causes yellow squash plant leaves and what you can do to deal with this problem. Check out the key points of the whole article to review every key detail:

  • Apply adequate water to keep plants away from both overwatering and underwatering stress.
  • Make sure you grow them in perfect spots where sufficient light falls.
  • Apply insecticides as soon as you see insects to avoid leaves curling and yellowing.
  • Cut off infected parts and apply appropriate treatments to control disease spread.

If you want squash plant leaves to stay healthy, follow every point carefully.

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