Why Are My Cucumbers Bitter?

“I am growing the same cucumbers this year as last year.  Every cucumber this year looks beautiful but tastes very bitter and is inedible.  I believe I am providing adequate water, though due to the heat the plants still wilt during the day. What can I do to improve the flavor? ” Lisa of Marietta, Pennsylvania

Answer: There are two things that can cause cucumbers to become bitter – the cultivated variety and environmental stress (heat stress, water stress, or disease). A great Oregon State University (OSU) article on the subject quotes the vegetable breeder, Jim Myers of OSU. He explains that the source of cucumber bitterness is caused by the natural plant chemical, cucurbitacin. It exists in high quantities in the leaves and stems of cultivated cucumbers. During stressful summers, concentrations can build up at different levels in the cucumber fruits as well; often at the blossom end. What’s odd is that sometimes a single plant may have some bitter fruits and some nice-tasting cucumbers, so taste each one to double-check before composting. The same plant may also produce sweeter fruits as growing conditions become better.

Non-Bitter Cucumber Varieties

Some varieties tend to reliably produce sweet cucumbers, even under stress. Here are five excellent cucumbers that resist bitterness.

  1. Katrina‘- The crisp, seedless, Beit-Alpha-type cucumber is also very disease-resistant and stays sweet.
  2. ‘Jibai Shimoshirazu’ – This heat-tolerant, Japanese snacking cucumber never gets bitter!
  3. ‘Green Light‘ – There is a reason that this cucumber was a 2020 All-America Selections winner. Its fruits are crisp, sweet, prolific, and resist bitterness.
  4. Marketmore 97– This classic, disease-resistant cucumber is known for its ability to stay sweet, even when stressed.
  5. ‘Unagi’ – After reading about this one, I plan to grow it next year. Its hybrid cucumbers are crisp, sweet, and very prolific.

I also recommend that you watch the video below to learn how to grow cucumbers to perfection. I know that it can be difficult in years where high heat, drought, and even excess rain are problems, but the video contains some good growing tips.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

About JESSIE KEITH


Plants are the lens Jessie views the world through because they’re all-sustaining. (“They feed, clothe, house and heal us. They produce the air we breathe and even make us smell pretty.”) She’s a garden writer and photographer with degrees in both horticulture and plant biology from Purdue and Michigan State Universities. Her degrees were bolstered by internships at Longwood Gardens and the American Horticultural Society. She has since worked for many horticultural institutions and companies and now manages communications for Sun Gro Horticulture, the parent company of Black Gold. Her joy is sharing all things green and lovely with her two daughters.

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