Geraniums have been a summer ritual for a century. Some gardeners tired of the standard red or pink cultivars, but in the past 25 years, growers started greatly expanding the selection of geraniums available. Now you can purchases these excellent container and bedding plants in colors ranging from white to fluorescent orange to striped; with foliage that comes in lemon, rose, mint or apple scents; and in a variety of sizes. Geraniums are tough and easy to care for, but giving them a little extra care will ensure superstar plants.
Without regular attention, your geranium will stop blooming and focus on leaf development. To keep its bright flowers throughout the summer, deadhead your plant weekly. Snap off stalks with dead flowers to encourage more blooms. Deadheading also keeps the petals from rotting and introducing botrytis blight, a moldy fungus that can infect an entire plant.
Geraniums need regular fertilizing throughout the summer, but they also need adequate watering at the same time to ensure the fertilizer is well-distributed. Using a water-soluble fertilizer will keep fertilizer salts from building up. Feed your plants every four to six weeks with 10-10-10 or 8-8-8 all-purpose fertilizer, or use a homemade, organic compost tea. Put compost into a burlap or cheesecloth bag and let it soak in a bucket for up to 10 days. Then use the "brewed" tea to water your plants.
You can grow geraniums in a wide range of temperatures, from as low as 45 degrees to as high as 80 degrees F. But for optimal blooming and growth, do not plant them until night temperatures reach at least 60 degrees and day temperatures reach at least 70 degrees F.