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Winter Squash · Cucurbita maxima

Why are my winter squash leaves falling off?

It is less common for winter squash to drop leaves unless they are dealing with significant stress. The most frequent cause is a severe infestation of squash vine borers that disrupts the plant's ability to transport water.

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Check these first

  1. Inspect the base of the main stem for holes or mushy tissue.
  2. Check the soil moisture level two inches below the surface.
  3. Look for signs of wilting during the cooler morning hours.

Likely causes

  1. Squash Vine Borer

    Possible

    How to tell: You will see sudden wilting of leaves followed by collapse and yellowing. Look for small holes in the base of the stem with sawdust like frass nearby.

    What to do: Check the base of the stem for entry holes. Carefully slit the stem vertically to remove the borer larva, then cover the wounded stem with moist soil to encourage new roots.

  2. Extreme Heat Stress

    Possible

    How to tell: Leaves droop heavily during the day and may turn yellow or brown at the edges. The plant struggles to keep up with moisture loss in temperatures above 95 degrees.

    What to do: Provide shade cloth during the hottest part of the afternoon. Increase watering frequency to keep the soil consistently moist but not waterlogged.

Leaf drop in other plants

Find out what's wrong with your winter squash

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

If the entire vine collapses suddenly, it is likely a borer infestation that is too advanced to save. It is normal for the oldest, lowest leaves to yellow and drop as the plant matures.

Stopping it coming back

Rotate your planting site every year to avoid overwintering pests. Use row covers early in the season to prevent moths from laying eggs on the stems.

Winter Squash: leaf drop? Check yours with a photo

Every plant is a little different. Take a photo of your winter squash and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Will my plant recover if it drops a few leaves?
Yes, if the main stem is healthy and the roots are strong, the plant will continue to grow. Just keep an eye out for further wilting.
Should I remove the fallen leaves?
Yes, clear away any dead or decaying foliage from around the base of the plant. This helps prevent fungal issues like powdery mildew.

Guides to these causes

More problems with Winter Squash

Back to the Winter Squash guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.