Ever since buying a number of tropical and citrus fruit trees to grow in pots, I've struggled with figuring out an ideal watering frequency. Part of this is because they live indoors half the year and outside half the year, meaning they experience an array of conditions, but also because I have found that conventional advice may end one step too soon.
Sometimes I water my trees per recommended standards, and they hold water for a long time. Other times, they dry out almost immediately and start showing underwatering conditions. It wasn't until I really started to pay attention that I made a few more crucial observations that helped me get my watering frequency under control.
Before diving into this one, I want to make two important caveats. First, the following is based only on observations for my own potted tropical fruit trees, which include several types of lemon, lime, mango, longan, guava, blood orange, kumquat, and more. They spend half the year indoors under grow lights and south-facing windows, and half the year outdoors. Second, commentary here is just a theory based on what I've noticed with my trees. Your mileage will vary.
So, with that in mind, let's jump into some observations we've seen over the years!