The seasonal changes will affect how often you water your Kumquat. Mainly, during the hottest summer months, you will likely need to increase how much you water this plant, especially if it grows in an area that receives ample sunlight. Strong summer sunlight can cause soil to dry out much faster than usual, meaning that you’ll need to water more frequently. By contrast, your Kumquat will need much less water during the winter, as it will not be in an active growing phase. During winter, you can get by with watering once every 2 to 3 weeks or sometimes not at all. For those growing this plant indoors, you should be somewhat wary of appliances such as air conditioners, which can cause your plant to dry out more quickly, which also calls for more frequent watering.