The annual geranium is an attractive plant that does well in hanging baskets. Although many varieties of geranium are drought tolerant, baskets tend to dry out quickly from exposure to air and sun, so your plants will do best with a potting mix engineered to retain water longer. You should also check the sunlight requirements for the type of geranium you plant so you hang the basket in the right location. Ivy geraniums, for example, prefer filtered sunlight while most other varieties enjoy six to eight hours of sunlight a day.
Line the basket with the moss, creating a small "bowl." Wetting the moss first may help it mold better to the sides of the basket.
Combine the potting mix with the slow-release fertilizer according to the fertilizer package directions. Add water retention beads if the potting mix does not already have them.
Cover the bottom of the basket with potting mix, about halfway up the bowl, and begin adding your geraniums.
Add more potting mix to cover the geranium roots, but only go as high as the plant was in its original container. Geraniums don't like to be planted too deeply.
Water thoroughly to settle the soil and let the basket drain, then hang it from a secure location that can handle the weight.
Remove spent blossoms from the geraniums frequently to encourage the plants to bloom again.