Bitter Fruit

Bite into a cucumber. Instead of crisp deliciousness, you get a bitter taste. What happened?!!? 

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Fruit can turn bitter for several different reasons. Unfortunately, once a plant produces bitter-tasting fruit, you may as well cut it off at ground level and start over because most of the fruit from then on will have the same taste. Also, the chemicals that cause bitterness can make you sick. In extreme cases, they can even kill you. So, what makes fruit turn bitter, and how can it be prevented?

Keep your harvest sweet with proper plant care. (Kate Russell)

Plants vulnerable to bitterness

summer squashes, melons, pumpkins, and cucumbers, and all other cucurbits can develop bitter fruit. To a lesser degree, the cabbage family (broccoli and kale) and members of the rose family can also be affected. The rose family includes almonds, apricots, pears, plums, peaches, loquats, cherries, quinces, and strawberries.


Causes of bitter fruit

Chemicals called cucurbitacins turn fruit bitter. When the plant becomes overly stressed, it increases the production of cucurbitacins, which then make their way into the fruit. Scientists believe plants produce these chemicals to discourage feeding by herbivores (and us). Common causes of stress that leads to bitter fruit include:

• Extremely hot (or cold) temperatures
• sunburn damage
• Overly dry weather
• Irregular watering
• Over-watering
• Poor soil fertility

Steps to prevent bitter fruit

1. Select varieties that are less likely to become bitter in the first place. In the world of cucumbers, this means choosing ‘burpless’ and ‘bitter-free’ varieties. 
2. Choose planting sites that provide stable temperatures. If your region regularly has temperatures above 90°F, provide your plants with afternoon shade.
3. Irrigate regularly, keeping the soil moist but not soggy.
4. Monitor soil health and fertility with a soil test from a reputable lab and make sure the soil pH is correct for the plants being grown.
5. Mulch around plants to stabilize temperatures, retain moisture, and eliminate weeds that will compete for water, nutrients, and sunlight.
6. Harvest fruit as soon as it is ready. The longer it stays attached to the plant, the more likely bitterness will occur.
7. Avoid prolonged storage and eat your produce while it is fresh for the best flavor.

If your cukes have started turning bitter, you can still eat much of the fruit by peeling it and tossing the stem end into the compost pile. If it still tastes bitter, compost it. The chemicals will disperse and break down.


Help your cucumbers, melons, and summer squash stay sweet with proper irrigation and sun protection.