In order to prevent rot in stored onions, they must be dried under the sun or artificially beforehand. Drying temperature in artificial dryers should not exceed 45-47 degrees. Onions that dried fully can be stored for up to 8 months at 0 degrees temperature and 70-75% relative humidity. If maleic hydrazide is used to prevent germination while the onions are in the field, the storage temperature can be increased up to 4 degrees. It is recommended to apply maleic hydrazide at a level of 500-1000 ppm 15-20 days before the harvest of onions.
Onion storage air speed should be 2 times higher than in normal warehouses. Care should be taken that the storage temperature does not fall below –1.5 degrees. 3-4 days before the onions are taken out of the warehouse, the temperature of the warehouse is increased to 10-15 degrees and the air speed is increased. Thus, the onions that go to a hot environment are prevented from getting moist and wet.