Choose the best cucumber

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Cucumbers remain a popular item to grow for fresh market and processing facilities. In 2015, 40,020 acres of cucumbers were planted in the U.S. The state of Florida leads the nation in acres planted in cucumbers, with Georgia a close second, according to USDA’s National Agriculture Statistics.

The majority of cucumbers for the larger market are planted in open fields as crops. However, many parthenocarpic varieties, such as the slicers Diva and Sweet Success Hybrid — which can be grown in greenhouses without the aid of pollination — are entering the fresh produce market. Many of these greenhouse varieties are grown on vertical trellises to save space and improve yield.

In addition to the increased availability of parthenocarpic varieties, there is also an increase in cucumber varieties that are gynoecious. These have mostly female flowers, generally ripen earlier than other varieties and have higher yields.

Some cucumber varieties combine the best of both worlds: they’re both gynoecious and parthenocarpic. These cukes have high yields without the need for pollination.

Yet no matter which varieties you end up selecting for your produce operation — or how far they’re being shipped — it is important to be knowledgeable about the best way to preserve your cucumbers’ freshness after harvest.

Maintaining postharvest quality

Because there are several bacterial and fungal pathogens that can cause postharvest losses in transit and storage, growers should carefully consider planting disease-resistant cultivar types. Thus, seed selection is of utmost importance and should be considered the first step in ensuring a maximum postharvest period, which will also help maximize your bottom line.

Temperature during storage and shipping is another variable that can affect postharvest quality. The Postharvest Technology Center at UC Davis recommends an optimum storage temperature of 50 to 55 degrees Fahrenheit (10 to 12.5 degrees Celsius) and relative humidity of 95 percent. Cucumbers can be stored up to about 14 days under these conditions before noticeable shriveling, yellowing and decay occur. Growers need to begin the postharvest treatment of cucumbers as soon as they’re harvested.

“The recommended best practice is to move harvested cucumbers to a canopy-shaded location in the field,” says Dr. Trevor Suslow, plant pathologist at the University of Berkley. However, he advises not to place the produce under a tree, where there is a chance of contamination from bird droppings — unless the crates or totes are covered well with corrugated fibreboard or a reflective sheet, which will also minimize heat buildup and water loss.

Cucumbers are sensitive to chilling injury at temperatures below 50 degrees Fahrenheit (10 degrees Celsius). At these temperatures, expect signs of chilling injury to show within two to three days. The telltale signs of this anomaly include water-soaked areas on the flesh of the cukes, pitting and accelerating decay.

Effects of ethylene and oxygen

Low levels of ethylene (1 to 5 ppm) during short-term storage and shipping of cucumbers will accelerate yellowing and decay. For this reason, it is recommended not to mix bananas, melons or tomatoes in with cucumbers. Ethylene measurement devices are available for growers and will detect critical concentrations of ethylene during storage and transportation. This device can give growers additional insights into the optimal conditions for storage. Low oxygen levels (3 to 5 percent) will delay yellowing and the onset of decay by a few days.

Further considerations

Overall appearance is important as it affects the marketability of cucumbers as well as shelf life. Cucumbers should be harvested while slightly immature, according to Suslow. Always cut cucumbers from the vine rather than pulling or tearing them. “Pulled end” is a quality defect used when establishing grade. Table and slicing cucumbers are primarily based on “uniform shape, firmness and a dark green skin color.” U.S. grades are Fancy, Extra 1, No. 1, No. 1 small, No. 1 Large and No. 2.

Source: UC Davis Postharvest Technology Center: Recommendations for Maintaining Postharvest Quality, Suslow and Cantwell.

Neil is a horticulturist and copywriter for the green industry.