Role of Potassium in Melon Production
Potassium maintains the ionic balance and water status within the plant.
Potassium and yield
Melons have a relatively high potassium requirement compared to nitrogen, with over 170 kg/ha of potassium typically being utilized by high yielding 50 t/ha crops (cv. Calhoun Gray – watermelon, USA).
Potassium, sugar and TSS
Potassium has a critically important role in ensuring top quality fruit by determining the level of sugars at harvest. It plays a key role in the transport of sugars to fruit (cv. Makdimon - Cantaloupe, Australia).
Potassium and cracking
Potassium also strengthens the melon skin, thereby minimizing the risk of cracking and damage during transportation (cv. Calhoun Gray - Watermelon, USA).
Potassium effect at growth stages
| Stage | Potassium effect |
| Pre-Planting | Promote strong early growth |
| Vegetative Growth | Maximize concentrations in leaf tissue prior to flowering |
| Flowering | Maintain plant growth and maximize flower numbers |
| Fruit Set | To minimize fruit disorders |
| Fruit Fill | Maximize high potassium levels in the fruit and minimize disorders |
See more on Melon Growth Stages.
General guidelines for Potassium application
Potassium is the most utilized nutrient by melon crops. K-requirements remain high until the beginning of fruit ripening. High potassium supply is critical in helping minimize cracking by thickening the rind. It is also very important in ensuring maximum sugar build-up in fruit.
Potassium deficiencies in melon
The young leaves are wavy. The older leaves are necrotic and will turn from yellowish-brown to brown and die. Fruits may be smaller and soft with lower sugar content and a reduced shelf life.
