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Zucchini gets yellow leaves: what are the most common causes and how to solve the problem?

We add zucchini to almost everything we eat: soups, salads, stir-fry dishes, smoothies, and more. If you eat as much zucchini as we do, then you know how important it is to grow it in the garden and get a good harvest. However, sometimes the perfect harvest is ruined by yellow leaves and diseased plants. Zucchini is very susceptible to many problems that can cause yellowing of the leaves. If this is not taken care of, a single yellow leaf can lead to the loss of the crop and eventually the death of the plant. It is important to identify the cause of yellowed leaves.

Why does the zucchini plant turn yellow?

Yellow leaves on zucchini - possible causes

Like all plants, zucchini produces chlorophyll. It is the pigment that turns a plant green and enables photosynthesis. Chlorosis is when the leaves of the plant turn yellow due to loss of chlorophyll. Chlorotic leaves can be a major problem for a plant, are unsightly and are easily burned by the summer sun. When a plant’s leaves turn yellow, it is usually a sign that a more serious issue is present. Here are some problems that occur in the garden that cause your zucchini leaves to turn yellow.

  • Nutrient deficiencies and pH
  • Over and under watering
  • Pests as a possible cause
  • Zucchini has been infected with a fungal or viral disease
  • Zucchini does not get enough sunlight

Zucchini gets yellow leaves: nutrient deficiencies and pH level

Zucchini plant dries up - nutrient deficiencies and pH level

Iron is a key element for chlorophyll production. A zucchini plant only needs a small amount of iron to produce healthy, green leaves, but there are a number of reasons why your plant may not be getting enough. It’s possible that the iron is trapped in your soil and can’t be absorbed by the roots. Also check the pH of your soil. Zucchini prefers a soil pH between 6.5 and 7.0, and if the soil is more alkaline, it can cause yellow leaves.

How to prevent nutrient deficiencies

Zucchini has yellow leaves - how to prevent nutrient deficiency

The first step in combating a nutrient imbalance is to have a soil sample tested. That way, you’ll know exactly what you’re dealing with and what to add. As with most things in the garden, yellowing zucchini leaves can be remedied by adding compost or well-rotted manure (chicken or horse manure). These soil amendments not only provide valuable plant food , but also help regulate a nutrient imbalance. Compost also helps regulate pH if your soil is too alkaline.

Overwatering and underwatering

Why do zucchini leaves turn yellow?

Another very common cause of yellow zucchini leaves is that the plants are getting either too much or too little water. Zucchini attracts nutrient-rich water through its roots. Also, most plants are 80% to 90% water, so they need adequate moisture to thrive.

Why do zucchini leaves turn yellow - causes and solution.

Zucchini plants don’t need as much water as you might think. About 2 inches to 3 inches of water per week is generally sufficient. If your zucchini doesn’t get enough water, the plants will begin to dry out and the wilted leaves will often turn yellow. Because there is not enough water in the soil, the plant cannot absorb nutrients through the roots and chlorophyll cannot be produced at a sufficient rate.

What should you do when over- and under-watering?

What should you do when overwatering and underwatering?

When you water, be careful not to water the leaves, as this can lead to fungal diseases. It is important that you know what type of soil you have and that you water especially carefully if you have heavy, clay soil. For clay soils, the solution is to add compost, which will loosen the soil and improve drainage. If overwatering causes the leaves to turn yellow, it’s best to wait until the soil dries and then water again, but this time in moderation.

Zucchini gets yellow leaves - under or over watering as a problem

If zucchini leaves turn yellow from drying out, you should water your bed. While it may be tempting to dump lots of water on thirsty plants, this can lead to overwatering and cause a whole new problem. Always water in moderation!

Zucchini leaves turn yellow because of pests

Zucchini leaves turn yellow because of pests

The zucchini plant is susceptible to pests such as aphids, spider mites and bugs. They can cause yellowing and wilting of the leaves as well as a blotchy appearance of the plant. Once the leaves turn yellow and you recognize these pests, it’s time to remove them from the garden to protect your zucchini. The best way to control troublesome pests is with beneficial insects. Mixed cropping is also a great way to beautify your zucchini patch and attract beneficial predatory bugs. These predators are often pollinators as well, so your zucchini will benefit twice.

White spots mean disease

Diseases in zucchini - pictures - downy mildew

Gray mold, zucchini yolk mosaic virus, fusarium wilt and downy mildew are among the major diseases responsible for yellow leaves on the zucchini plant. Remove diseased parts such as leaves and stems from the plant. Use organic neem oil or soap solution if the infection is widespread.

Yellow leaves in zucchini – not enough sunlight.

Yellow leaves on zucchini - not enough sunlight

If there is not enough bright light, zucchini leaves will begin to turn yellow. Zucchini needs 4 – 5 hours of sunlight every day. If your plant is in the shade, move it to a place where it will get enough light.

Can you prune yellow leaves off zucchini?

Is it possible to cut off yellow leaves on zucchini?

Pruning zucchini leaves is never a bad idea, however, there are a few things to keep in mind. Feel free to remove a few yellow leaves, but at least leave some leaves growing. Your zucchini should never be completely devoid of leaves. Cut them near the stem, but be careful not to cut the stems themselves or the plant will be more susceptible to disease.