The Several Stages of Important Thinning Practices
The first and important stage in thinning your watermelon (Citrullus lanatus) plants begins once they have germinated in their prepared site in the garden. In preferred warm conditions, watermelon seeds pop their heads out of the soil anywhere from a week to almost two weeks after planting.
If you started your seeds in peat pots and transplanted in the garden, you might already have only planted the preferred amount per hill – about three plants. If not, you will need to follow the thinning procedures for seeds planted directly in the garden plot.
Properly cared for watermelon plants planted in preferred conditions develop into large, robust plants, so you don’t want to overcrowd them by having too many plants growing out of the same hill. This cuts down on proper air circulation, which can lead to pest and disease problems.
The procedure for thinning after planting and germination include:
- Wait until the germinated seedlings have three to four leaves before thinning.
- Select the healthiest looking three to four seedlings and remove the others.
- Using clean garden snips, clip off the unwanted seedlings at ground level.
Thinning Developing Fruit
Although watermelon plants produce male and female flowers, only some of the female flowers develop into fruits. Do not be alarmed if many of the female flowers fall off the plant without developing into fruits because this is normal.
It does not harm the plant if you don’t thin the developing watermelons, but if you want bigger melons, you will need to thin.
Steps in thinning include:
- Watch the vines for the female flowers to develop into small melons.
- Wait to thin until the developing melons reach the size of about a ping-pong ball, as some may naturally drop from the vine and you don’t want to remove the melons too soon or you risk losing a crop.
- Using clean garden snips, remove any watermelons that are misshapen, or look to have a problem like blossom end rot.
- For large varieties of watermelons, snip off all the melons other than the two healthiest ones.
- If you are growing smaller varieties, you can leave four to six developing watermelons on the plant.
Expert Tip: Make sure to use sterilized pruning blades when pruning your melons off the vine so you don’t transfer disease problems to the plant. It is as easy as wiping the blades off with alcohol