Harvesting watermelons

Watermelons are warm weather crops and they require high temperatures. Photo by Rachel Mabala

What you need to know:

  • Although the fruit is succulent, it is not uncommon for farmers to harvest immature watermelons, which are white with excess water. Such harvests go to waste when found not to be ready for consumption as consumers look for the deep red-fleshed slices.
  • There are deflectors that are used in determining the sugar content in relation to ripening, but gadgets may be readily available for smallholder farmers.

How do I know my watermelon is ripe?

Juliet Nabosa

Dear Juliet
With multiple knocks, farmers can improve maturity prediction accuracy by more than 70 per cent in determining if watermelons are ready for harvesting. Mature and immature watermelons tend to produce different sounds.
A dull hollow sound signals that the fruit is ripe. A mature watermelon has less water compared to a one still growing - which produces a high-pitched sound.

Ripe watermelons produce low-pitched sounds, but one has to gently hit several of them with a stick to boost chances of accuracy.

One can identify seven out of 10 ripe watermelons using the sound trick.
Dying of the vine tendrils is another sign that the melons are ready for the market. Some varieties tend to be soft at the lower scar end.

After the first confirmation of the ripe fruit, the others should be ready for harvesting in about two days.
Delayed harvest may result in losses as the fruit cannot stay long after ripening.
The bottom part of the fruit also turns lighter or golden green.

For best quality fruits, irrigation should be stopped for about a week before harvesting. This allows for utilisation of the water in the fruit. Reducing the moisture content increases the sweetness of the melon as a result of high concentration of sugars.

Although the fruit is succulent, it is not uncommon for farmers to harvest immature watermelons, which are white with excess water. Such harvests go to waste when found not to be ready for consumption as consumers look for the deep red-fleshed slices.
There are deflectors that are used in determining the sugar content in relation to ripening, but gadgets may be readily available for smallholder farmers.
Answered by Jeff Makori a horticulture agronomist.