How Often Water Container Plants?
Watering container plants is definitely a trial-and-error process as you learn the water needs for your particular plant in your unique situation.
First, what kind of plant do you have, and is it in shade or sun? Just as in the landscape, plants in containers have different water requirements, so first do a little research as to whether your plant is generally categorized as low, medium, or high water-use.
Next, what type of container is it in? Unglazed terra cotta planters are extremely porous, and will need more water than glazed ceramic pots, plastic containers, or other materials. Also important is the maturity of the plant. Was it recently planted, and is it in the proper size container?
A good rule of thumb is to only plant up by one size container as your plant grows and you transplant it. Too much soil surrounding the rootzone can set up a situation where the water stays too wet around the perimeter of the container, leading to potential disease and other issues.
Next, is your container in full sun? What season of the year is it? In full sun in the middle of summer, many container plants might require water every day or even TWICE per day. And any wind at all will dry out your plants even faster. If the container is small enough to lift, I like to pick it up and gauge how dry the potting soil is by the weight of the pot.