In cellar storage structures, temperatures are reduced slightly below room temperature (about 15°C). These are underground rooms, which are well insulated to outside temperatures and have proper ventilation. These are meant for short term storage of root crops, potatoes, apples etc. during the winter months as the temperature is not low enough to prevent the action of many spoilage organisms or the plant enzymes. However, deterioration is slowed down considerably. Humidity should be carefully maintained in the storage cell as high moisture promotes fungal growth whereas shriveling and drying may occur in dry conditions.