Grow For It! Growing the ‘bitter’ out of cucumbers

There’s nothing worse than biting into a bitter cucumber.

It ruins the whole fresh garden salad. It’s even worse when the cucumber comes from your own garden! Did you grow some bitter cucumbers this summer? If so, read on to learn what you can do next year to avoid this problem.

Cucumber Botany. Cucumbers are members of the cucurbits family of vegetables, which includes squash, melons and pumpkins. Cucurbits contain chemical compounds known as terpenoids that are in some measure responsible for flavor and scent.

The terpenoids responsible for bitterness in cucumbers are cucurbitacins. These substances are present in the roots, stems, leaves and fruit. Specifically, two genes account for the bitter taste or lack of, a dominant one that makes the cucumber bitter and a recessive one that inhibits the formation of cucurbitacins, thus suppressing the bitterness.

Nevertheless, the accumulation of cucurbitacins is generally not heavy enough to make the fruit bitter, or if it is, the concentration is at the stem and just under the skin. Bitterness in cucumbers also appears to be controlled by the presence of an enzyme know as elaterase. Elaterase converts cucurbitacins to non-bitter compounds.

Scientists believe that the elaterase activity operates independently of the genes that control bitterness, and that when the level of bitterness in cucumbers varies from year to year, it is due in part to environmental effects that either stimulate or suppress the elaterase activity. It is the presence of cucurbitacins in cucumbers that also cause digestive distress for some folks by making them burp.

Environmental Factors. Cool temperatures and shady sites seem to trigger bitterness in cucumbers. Researches note that temperature variations of more than 20 degrees, moisture stress, and storage of cucumbers on the vine too long or near other ripening vegetables also cause bitterness. They note, however, that fertilization practices, plant spacing and irrigation frequency had little consistent effect on the number of bitter cucumbers produced.

Recommendations. Start your cucumbers in the spring by direct seeding when the soil temperature reaches 60 degrees. Avoid growing them in cool or shady locations. As with all vegetables, fertilize and mulch. Keep them well watered and adjust the irrigation when there are heat spells to avoid stressing the plants. Pick the cucumbers when they are smaller rather than larger. Perhaps one of the best ways to reduce the chance of growing bitter cucumbers is to pick hybrid varieties, especially ones designated as “burpless”. These varieties have been specially bred to be bitter-free.

Master Gardeners are available to answer home gardening questions Tuesday through Friday, 9 a.m. to noon, by calling 530-621-5512. Walk-ins are welcome.

The office is located at 311 Fair Lane in Placerville. For more information about public education classes and activities, go to the Master Gardener’s Website at ucanr.edu/sites/EDC_Master_Gardeners/. Sign up to receive online notices and e-newsletter at ucanr.edu/mgenews/.

Master Gardeners can also be found on Facebook; just type in Master Gardeners. If you want to ask questions in person, Master Gardeners are available most Saturdays at the Placerville Farmer’s Market and most Sundays at the El Dorado Hills Farmer’s Markets.