Gardeners throughout the United States have vast selections in geranium cultivars. Hardy geranium (Geranium spp.) or ivy geranium is well-suited for use in hanging baskets and container gardens. Old-fashioned garden geranium (Pelargonium x hortorum) grows well planted in containers as well as directly in the ground. Geraniums are frost-sensitive and require winter protection. Gardeners have several options when it comes to keeping geraniums safe until warm springtime weather returns.
If your geraniums are already growing inside hanging baskets or containers, winter care is minimal. Before frosts arrive, bring the containers into a warm area indoors. The plants perform best when indoor temperatures are between 45 and 70 degrees Fahrenheit. Select a location that receives bright light. Do not be surprised if the plants continue growing and flowering throughout winter. Water the geraniums monthly, saturating the soil. Plants do not require frequent watering, as they do during the warm growing season. Fertilize plants monthly with a half-strength solution of a 10-10-10 water-soluble blend. Return plants outdoors in springtime.
Dig the geraniums from the planting site before the first frost. If you have multiple plants, using a trough-like container or large planting tray works well. The large tray contains the plants together, as crowding is OK. Trim the geranium stems back to approximately 4 inches in length. Use pruning shears and make your cut at a leaf node. If the root system is too large to fit inside the container, trim it back by approximately one-third. Use a lightweight potting mix in the containers and water it before planting the geraniums. Plant the geraniums into the container and water again. Place the containers in a bright area indoors and water and feed monthly, as you would for containerized geraniums.
If you prefer to let the geranium plants go dormant until springtime, you can use your garage to store them. This method works well for those who do not have a warm, bright area that allows the plants to continue growing throughout winter. Lift the geraniums from the ground and prune the branches back to 4 inches in length. Pot the geraniums into a lightweight potting mix and water well. Place the containers in a dark garage area that is frost-free. Check the containers every two to three weeks and apply water if needed. Do not allow the soil to completely dry out. When warm spring temperatures return, replant the geraniums into the garden.
Geraniums prefer growing in partially shady to partially sunny conditions. Plant the geraniums in soil that drains well and is rich in organic materials. Amend the planting site with compost or manure, if needed. Plants will flower and perform best with regular water applications, especially during hot weather. Check containerized plants regularly and if the top 2 inches of soil is dry, water the geraniums. Fertilize the plants every two weeks to once per month. Use a water-soluble 10-10-10 blend.