Carol Siddall, Master Gardener
One of the favorite plants in my garden is the Geranium. Few plants offer such a great variation in flower color, growth habit, leaf pattern, and scent. Lush growing geraniums look good in a bed all by themselves, mixed in with other annuals, or used as an edging in your flower garden. In fact, these plants are perfect for any spot that calls for a splash of vibrant color.
In our area, geraniums cannot make it through the winter outside unless you cover them to keep them from freezing when the hard winter hits. I am fortunate to have a greenhouse, so that is where my plants winter. (Needless to say, all my geraniums are in pots.) Another benefit to a greenhouse is that geraniums love the greenhouse! It is a joy to enter the greenhouse in the winter time and see a room full of color! If you plant your geraniums in your flower beds, be sure to wait to do so after all danger of frost has passed and the soil temperature has reached 60 degrees F.
Geraniums like a lot of sunlight. With less sun, the plants will bloom more sparsely. But, during the hottest summer months too much sun will hurt. A location providing afternoon shade will keep your geraniums blooming all season. If in containers, you can move them if you realize they are getting too much hot sun.
Geraniums do not like WET feet. Many container grown geraniums are killed because of too much water. Make sure there is good drainage in your pot. You can check if your geranium needs water by scratching the soil surface with your finger or use a moisture meter.
While soil types are important, it is not too critical for geraniums. They will grow in most any kind of soil, providing there is good drainage. Compost added to your garden soil will give them an added boost. For containers, a good mix should have excellent drainage, good aeration with good water retention capabilities. Fertilizer is also important as they are heavy feeders. I feed my containers with a timed released fertilizer when I take them out of the greenhouse. If they are in the ground, they could use a feeding at least once a month with a balanced, water-soluble fertilizer such as 20-20-20, or use a timed released fertilizer when planting.