When it comes to the taste of summer, there isn’t anything much better than a cold slice of watermelon. It’s practically a staple for any family picnic. However, biting into a melon that isn’t very sweet is kind of like biting into a chocolate chip cookie only to discover it’s a raisin cookie. It truly can be disappointing.

When a melon lacks in sweetness, there’s a misconception the soil in the field is bad or the melons have cross pollinated with another plant to give them a less-than-sweet taste. This isn’t the case. The No. 1 problem typically associated with watermelons, cantaloupes, honeydews and other melons is actually related to the amount of sunshine that field or garden receives.

In a wet, cloudy growing season, it’s difficult to get a melon to sugar up. This makes sense because sugar production in any plant is driven by photosynthesis, and that’s directly affected by the amount of sunlight available.

Obviously, gardeners and producers can’t control the weather, but there are some things that can be done, and shouldn’t be done, to help ensure a good harvest. First, take care of the crop, making sure to use preventative fungicide sprays, good fertility and proper irrigation to maintain a healthy plant canopy. Without a good canopy the plant won’t have the necessary foliage available to produce high sugar levels when the sun is shining.

Next, keep an eye out for crop pest problems and diseases, particularly anthracnose, downy mildew, fruit rot, etc. Use preventative fungicide sprays to help prevent these from happening.

If you’re dealing with a particularly wet season, the weeds easily can get out of hand. Growers may need to do hand weeding to clear out large weeds so they can find the crop for harvest. Unfortunately, there are very few postemergence herbicides cleared for vegetable crops. One product called Poast, is labeled for use on several cucurbits and controls several grassy weeds. Make sure any product used is labeled for the specific crop and weed species that is causing problems.

Don’t spend money on snake-oil treatments for the crop. Fertilizer supplements and magic elixirs that make claims to cure all sorts of crop ills such as low sugar levels, are a waste of money.

Insects often are a problem, especially early in the season for developing plants, so be sure to continue to monitor insect populations and treat with the appropriate materials when needed. Always read and heed the labels.

Keep in mind different kinds of melons differ in genetic potential to accumulate soluble solids, as do cultivars within kinds. If the seed source is reliable, then poor sweetness is usually due to an environmental issue.

David Hillock is a consumer horticulturist with OSU cooperative extension.

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