Warehouses , three important factors such as variety selection, cultural processes and storage conditions should be considered.
Variety selection is an important factor in dry onions that will be stored for a long time. The varieties that are suitable for the domestic and foreign market demands of the producer and for which the storage period is determined should be selected. In our country, there are many dry onion varieties known with their special names, especially Banko onion, Valanciana onion, Keş onion, Fito delfos onion, Swale F1 onion, Tan 88 onion, Bereket onion, Songur onion. In general, it is desirable that the onions are whole, intact, clean, frost-free, with dry stems and at least two layers of dry outer skin.

Onion Harvest

Dried onions should be free of rot and defects, visible foreign matter, wetness, foreign taste and odor that would prevent their consumption. Dry onion stalks should be neatly cut or twisted and no longer than 4 cm. The skin structure and the number of skins are important features in storage, and the thick-necked onion varieties with thick and many skins are very durable. The shell structure is also important in terms of the contamination of fungi in the warehouse. The number of shells in winter varieties is between 2 and 5. In general, varieties with higher than 10% dry matter and rich in protein and carbohydrates are suitable for long-term storage.

Cultural processes that are effective in onion storage include planting, planting time, irrigation, fertilization, disease and pest control, harvesting and drying. The maturity of onions begins with the yellowing of the leaves and ends with the softening of the neck and tilting. At the time of harvest, 2/3 (2/3) of the green part above the soil should be dry. Harvest begins when 80% of the onions are ripe. Early harvest causes low yield and as a result, damages in drying and storage. In the late harvest, however, sunburn on the tuber and bark shedding occur due to dew-frost.

Onion Storage

Drying must be done in order for the dried onions to be stored to mature and to form the desired skin color. Drying can be done in the field or in the warehouse. Drying method is used more in the field. In drying, the tubers should be arranged so that they are not exposed to direct sunlight and the tubers should be covered on rainy days. The drying process takes 15-20 days on average. Drying can also be done in the warehouse. If the onions brought to the warehouse after the harvest are wet, a good ventilation should be provided in the warehouse for three weeks in order to dry them by removing an average of 45-50 kg of water per ton from the bulb.