Water and Fertilizer:
Geraniums are hardy plants and can tolerate medium drought. So you should allow the soil to dry out a bit between waterings (allow the top 1″ to dry out before watering again). You should always try to avoid watering directly over the blooms of your geraniums, because the flowers do not like to get wet. Your fertilizer schedule will be according to which type you choose (granular is usually good for 2-3 months, liquid can be applied every water or every 7-14 days). The key to fertilizing a geranium is to ensure it is not over fertilized, so when you apply use only 50-75% of what the recommended application rate is. Geraniums grow best with a 10-10-10 fertilizer, but a blooming fertilizer (15-30-15) is often used and yield similar results.
Zonal geraniums are the most common patio geranium. These geraniums are not dead-headed naturally and will require a little attention to ensure they bloom prolifically all season.
You will want to dead head your geraniums once a week, and more frequently if there has been heavy rain, as this disintegrates the blooms and leaves your plant looking shabby. When you dead head your geranium follow the flower stalk down to where the stalk meets the stem of the plant, 1″ above where the stalk and the stem meet you will cut the flower stalk off. You will remove all the blooms that have no more buds, or that have wilted petals. And this will promote the young buds to bloom faster.
With these simple, easy tips you can keep your geraniums glorious all season long!