I have a long (8ft+) butternut squash vine that seems to be healthy (green leaves) and producing both male and female flowers. It grew all summer and is still alive and healthy. I see many nice female flowers (the baby fruit part is 2--3 inches long) get pollinated; I even hand-pollinated a few flowers myself. However, after pollination, they all turn slightly yellow, shrivel, and rot (see below).

I live in zone 9b and it's starting to become cooler, so I don't have much hope for this season. What can I do better?

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1 Answer 1


Butternut squash is able to produce fruit reliably if the nights and days are warm, there is moisture available and the vine is growing vigorously. In my area the nights in July and August are warm and if the soil is fertile and there is occasional rain the fruit will be rewarding. However in September cooler nights come, and the bright green leaves start to turn white with mildew and once you lose a few big leaves the vine continues to grow but the plant is no longer vigorous and will start abandoning fruit even if pollinated and beginning to grow. Once that starts to happen you can leave the already established fruit on the vine to ripen fully, but cannot expect more fruit to grow. If you see mildewed leaves then basically that's it for the season.

  • I will start the squash earlier next year to give it ample time to grow during the warm months.
    – Vimal
    Nov 19, 2019 at 15:07
  • I think I know why they didn't mature -- the squash seeds were probably from a F1 hybrid variety and were likely sterile. The seeds I planted from the same variety ended up looking very different from one another, both the leaves and the flowers. I will never make the same mistake again!
    – Vimal
    Jul 4, 2020 at 22:04

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