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How can you tell if a watermelon is ripe? Maturity is difficult to determine without plugging (cutting a small wedge) and testing. It is VERY important not to harvest melons when they are immature because total sugar does not increase after they come off the vine. Four commonly used methods (harvest indices) for determining watermelon maturity are: METHOD CHARACTERISTIC CHANGE IN FRUIT

1. Color of: Color of rind on the part of the "ground spot" melon touching the ground ("ground spot") changed from greenish-white to pale yellow when ripe.

2. Sound when thumped: Ripe melon emits a dull or hollow sound, compared to a clear ring of an immature fruit.

3. Condition of tendril: Tendril at the point of adjacent to stem end. attachment withers and dried out at fruit maturity.

4. Feel and appearance of: Rind feels slightly rough with rind surface dull, opaque appearance, compared to the shiny, glossy, smoother feel of an immature fruit.

In general, no one method will guarantee identification of the desired stage of fruit maturity during the critical 10-14 day period in which a typical red-fleshed watermelon passes from immature pink to red ripe to over-ripe. Indeed, these four methods are only indicators of fruit ripeness and the exact stage of maturity can only be determined by "plugging" or sampling a section of the fruit for flavor and soluble solids. Obviously, "plugging" is a destructive process and can only be used to determine the maturity of a representative sample of a grower's field on a given date. Plugging to verify the accuracy of the four non-destructive methods outlined above is highly recommended, especially for someone who is not highly experienced in assessing watermelon maturity.

Relative fruit size is another non-destructive harvest index for estimating watermelon maturity. However, extreme caution must be exercised when using fruit size alone as a harvest index. While fruit size is characteristic for each variety at maturity fruit size can vary considerably because of difference in (a) fertility and moisture conditions of the soil, (b) plant spacing and density, and © time of year. In general, the first fruit set are the largest and fruit size becomes smaller as the season progresses. Soil productivity may even vary considerably within the same field resulting in a distinct variance in the size of mature fruit in different sections of the field the same day. The degree of reliability or effectiveness of nondestructive harvest indicates may vary among varieties. Thus, the grower or home gardener will need to adopt a strategy for harvesting each variety based on wise use of plugging to determine actual fruit quality correlated with the four nondestructive harvest indices.

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