The importance of proper watering cannot be stressed enough for your container garden plants. Container Gardens are exposed to wind and sun so they dry out quicker than plants in the ground. There are no exact rules about watering your container garden plants. You have to become acquainted with the needs of various garden plants. The best tip is to examine them daily and water the plant when the surface of the soil begins to look dry. Feeling the soil will also help you determine the moisture needs of your container garden. Or, take the easy way and invest in a water meter if you are not sure.
How much and when to water will depend on the kind of plant and soil, the type and size of container, and the amount of exposure to sun and wind. Climate and the weather also play their part. During hot spells most plants in your container garden need daily water, except those in small clay pots, which may require it twice. Some plants, like fuchsias and tuberous begonias, wilt when dry, but geraniums and succulents are not so sensitive to neglect. On the other hand, it is good to let soil dry out a little between watering. This prevents the soil from depleting its nutrients.
Since un-glazed containers dry out quickest, watch them more closely. Wooden tubs, window boxes, and planters dry out more slowly; metal is the slowest of all. Groups of plants in large containers keep moist longer than single specimens.