Blossom End Rot
Going crazy over Blossom End Rot on my watermelons, had soil tested with no real deficiencies. Limed area in the fall previous to planting. I keep losing my melons and tired of all the work involved just to lose my melons to this rot! Please help.....
Lenawee County Michigan
Blossom end rot is caused by calcium deficiency. This deficiency can be because there isn't enough calcium in the soil, or because plants aren't very good at moving calcium around. I would start by double checking your soil test to see where your calcium levels are at. If those are good, focus on consistent watering, especially when it is dry. Try to keep the moisture levels consistent, as wild fluctuations in water availability can promote blossom end rot. Having water consistently available helps the plant move calcium throughout the plant.
Another thing to look at is the amount of nitrogen fertilizer you are adding, too much N fertilizer can make the plant focus on vine growth, which can deplete available calcium and promote blossom end rot.
Another consideration is variety. If you are consistently having issues with one variety, try a few new varieties this year. Different varieties have different levels of susceptibility to blossom end rot. In general, long fruit are more prone to getting blossom end rot that shorter ones.