Why is My Squash Bitter?

"Long of Naples" squash

“Long of Naples” squash growing in our backyard.

It’s the bees.

Squash is a member of the Cucurbitaceae family, one of the most difficult vegetables to save seeds from. Cucurbitaceae have both male and female flowers and lots of wild, inedible relatives. Cross pollination is what Cucurbitaceae want to do. If you want to save seed and you take the precaution of taping up the flowers, bumblebees and solitary bees can chew their way through the tape to get at the pollen. In short it’s really easy to breed a freak Frankensquash or Frankencucumber, which can actually be toxic.

Cynthia, a Root Simple reader in Texas, alerted me to an interesting hazard with bitter out-crossed Cucurbitaceae. According to Tony Glover, regional extension agent at the University of Alabama,

The bitter taste of squash and cucumbers comes from a natural organic compound called cucurbitacin . . . which can cause severe stomach pains. If the fruit are extremely bitter you might as well pull the plant up and start again because they will not likely become un-bitter.

Cross-pollinated freak seeds are the culprit. And even reputable seed companies can screw up, especially with Cucurbitaceae.

Glover goes on to note that mildly bitter squash could just be a symptom of stress: heat, cold or lack of nutrients.

Have you ever had problems with unintentional freak vegetables? Cynthia’s mishap was with a “Long of Naples” squash a.k.a. squash baby, just like the one pictured above. I’m hoping not to have this problem!

Leave a comment


  1. I didn’t realize that Squash Baby was a Long of Naples squash. I followed the story of Squash Baby.

    The previous winter, I had another bitter vegetable adventure when I grew turnips. I steamed a large one, put some butter on it, and took a bite. It was so bitter that I couldn’t eat it. This led me to some interesting reading about how some individuals are more sensitive to compounds in cabbage-family vegetables. It’s a question of genetics. It made me wonder what my European peasant ancestors did if, due to their genetic inheritance, they were extra-sensitive to those compounds in vegetables that were their staple crops (before the potato). I don’t have any issues with eating other members of the cabbage family–only turnips.

    Here are some interesting links:


    • Hey Cindy–thanks for some really fascinating links. The de-bittering of our foods is an interesting story. As is the genetics of taste–cilantro is a good example of this.

  2. Well, now this explains a problem I had with pickling cucumbers a couple years ago. They were so horribly bitter, I couldn’t eat them. I was really bummed, too, because I do like pickles and had planned to make quarts and quarts of gherkins. Instead, I fed them to the chickens–who were delighted and weren’t bothered by the bitterness at all.

  3. This is such a relief to read. Earlier this year I had a smoothie with an entire cucumber in it, and I felt like knives were twisting in my stomach. I haven’t touched a cucumber since then, fearing that I had developed a cucumber allergy. I’ll be looking deeper into this and perhaps trying a few bites of pickles, which I have missed so much.

  4. Interesting! At the end of summer I got a few VERY bitter inedible cucumbers from my CSA. I had been planning to make refrigerator pickles but the day got away from me, and the next day I ate one in a salad. Or, rather, picked it out of my salad after having a bite. Out of the 6 or so cucumbers I got that week, 2 were horrible. I too fed them to my chickens.

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