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Home » Why is my crookneck yellow squash bumpy skin: What’s Wrong

Why is my crookneck yellow squash bumpy skin: What’s Wrong

crookneck yellow squash bumpy skin

Crookneck Yellow Summer Squash


Squash comes in a wide range of colors, sizes, and textures, with common varieties including zucchini and yellow summer squash. Yellow squash, also known as crookneck squash, is a popular summer vegetable that is known for its characteristic yellow skin and sweet, yellow flesh. One thing that may surprise some gardeners, however, is the presence of bumps on the skin of their yellow squash. In this article, we will explore the reasons why yellow squash may develop bumps, and what can be done about them.

What is Crookneck Yellow squash?

Crookneck squash is a cultivar of Cucurbita pepo and is characterized by its yellow skin and sweet yellow flesh, as well as its curved stem. It is often used as a summer squash and is typically harvested when it is less than two inches in diameter. The skin and quality of the squash degrade as it reaches full maturity. It should not be confused with other similar-looking varieties of Cucurbita moschata or C. pepo.

Why is My Squash Bumpy?

The most common cause of bumpy squash is a mosaic virus. Squash, along with other members of the cucurbit family, can be affected by several different varieties of mosaic viruses. These viruses are spread by insects, soil, and other means, and can cause fruits to form with knots and bumps in their skin. The texture of these squash is usually rough and patchy. In some cases, squash may become bumpy if left on the vine for too long. This is especially true for summer squash varieties. However, it is more likely that the bumps are caused by a virus, so it is best to inspect carefully to determine the cause.

Causes of Yellow Squash Bumps

  1. Cucumber mosaic virus: The most common cause of yellow squash bumps is the cucumber mosaic virus. This virus is spread by aphids and thrips insects and causes raised, yellow bumpy squash and warty regions on the fruit’s skin.
  2. Watermelon Mosaic Virus: This strain of mosaic virus affects both winter and summer squash, and can cause green overgrowths on the exterior of summer squash, as well as knobby protrusions on winter squash.
  3. Papaya Ring Spot Virus: This virus produces malformations on the skin with color breaks over the surface.
  4. Zucchini Yellow Mosaic Virus: This virus affects zucchini and results in distorted fruits and squash is warty looking.
  5.  Excess calcium in soil: Excess calcium in the soil can also cause yellow squash bumps. Too much calcium can interfere with the plant’s ability to absorb nutrients, causing the squash to become lumpy.
  6. Rapid growth: If squash plants are allowed to grow too quickly, they can become bumpy as well. This is usually caused by the plant being over-watered or over-fertilized.
  7.  Boring insects: Insects such as squash vine borers can cause yellow squash bumps by boring into the fruit, causing it to become lumpy.

How to Prevent Lumpy & Bumpy Yellow Crookneck Squash Plants

To prevent your squash plants from developing bumps there are several steps you can take. These include:

  1. Purchase-resistant seed or starter plants: Some varieties of squash are naturally resistant to mosaic viruses and other diseases that can cause lumpy fruits. By planting these varieties, you can greatly reduce the likelihood of your squash developing deformities.
  2. Control weeds and apply mulch: Weeds can harbor pests and diseases that can affect your squash plants. By keeping your garden free of weeds and applying a layer of mulch around your plants, you can help prevent pests and diseases from spreading to your squash.
  3. Take good care of your plants: Squash plants that are healthy and well-cared for are more likely to withstand disease and produce healthy fruits. Make sure to water your plants regularly, provide adequate nutrients, and remove any damaged or diseased plants from your garden to prevent the spread of disease.
  4. Plant a cover crop: Planting a cover crop, such as wheat or grain, around your squash plants can help prevent the spread of mosaic viruses. Aphids, which are common vectors of these viruses, are attracted to the cover crop and may feed on it instead of your squash plants, reducing the likelihood of transmission.
  5. Sanitize tools: Mosaic viruses can be spread through contaminated tools and equipment. To prevent the spread of disease, make sure to clean and sanitize any tools or equipment you use in your garden regularly. This will lessen the likelihood of illnesses spreading from one plant to another.

How to Grow Healthy Crookneck Squash

To grow healthy crookneck squash, follow these steps:

  1. Prepare the soil: Choose a spot in your garden that receives full sun, has well-drained soil, and is free from the dangers of frost.
  2. Plant the seeds: Start squash plants indoors and transplant them when the soil is warm and ready to support plant growth. Alternatively, you can directly sow seeds in the soil when the soil is free from the dangers of frost.
  3. To ensure that the plants have enough space to spread their vines and produce healthy fruits, you should provide enough space between each plant.
  4. Crookneck squash typically takes between 5-10 days to germinate.
  5. Water regularly: Make sure to water the squash plants regularly and maintain the moisture level around their shallow roots.
  6. Fertilize: Apply a balanced fertilizer to the soil to provide the necessary nutrients for growth.
  7. Mulch: Apply mulch around the squash plant to keep the soil warm, prevent weeds, and retain moisture.
  8. Monitor the plants for pests and diseases and take appropriate action if necessary.

By following these steps, you can grow healthy crookneck squash that produces flavorful and fleshy fruits.

Frequently Asked Questions

Can you eat bumpy yellow squash?

Yes, you can eat yellow squash with bumps. While the bumps may not be aesthetically pleasing, they are not harmful to consume. The bumps are caused by the mosaic virus, which does not affect the taste or safety of the squash.

Can you eat the skin of crookneck yellow squash: Is It Edible?

Yes, the skin of yellow squash is edible.

Is it ok to eat bumpy yellow squash?

Yes, it is safe to eat bumpy yellow squash. The bumps are caused by a virus known as the mosaic virus, which does not pose any danger to humans upon ingestion. The squash may have a slightly discolored appearance, but it is still safe to eat.


In conclusion, yellow squash bumps can be caused by several different factors, including mosaic viruses, excess calcium in the soil, rapid growth, and boring insects. To prevent your squash plants from developing lumpy or deformed fruits, it is important to purchase resistant seed or starter plants, control weeds and apply mulch, take good care of your plants, plant a cover crop, and sanitize tools. Additionally, to ensure healthy crookneck squash, it is important to prepare the soil, plant the seeds, water regularly, fertilize, mulch, and monitor for pests and diseases. With proper care, you can enjoy a healthy crop of delicious yellow squash.

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