You can cultivate geraniums indoors, provided you are referring to plants of the Pelargonium genus, which are commonly called geraniums. These tender perennials are excellent candidates for year-round indoor care or for being brought inside to survive the cold winter months. They can thrive indoors with the right environmental adjustments, allowing them to transition successfully from summer outdoor containers to indoor houseplants where they offer foliage and occasional blooms.
Essential Conditions for Indoor Growth
Achieving successful indoor growth for Pelargonium hinges on replicating the bright, sun-drenched conditions of their native South African habitat. Place them in a location that receives ample bright, direct sunlight for a significant portion of the day. A south-facing or west-facing window is often the best choice, especially during the low-light winter months, as insufficient light will result in pale, etiolated (leggy) growth and a complete lack of flowering. If natural light is limited, supplemental grow lights can be installed, such as placing the plant beneath a fluorescent bulb for 16 hours daily to ensure adequate energy for photosynthesis.
Maintaining a consistent and appropriate temperature range directly influences the plant’s metabolic processes. During the day, geraniums perform best with temperatures between 65°F and 75°F. However, a slight cooling period at night is important to conserve sugars, which helps promote stronger stems and better blooming. Ideally, nighttime temperatures should drop to a cooler range of 55°F to 60°F. Avoid placing the plant near cold drafts from windows or direct heat sources like vents, as these sudden fluctuations can cause stress and inhibit healthy growth.
Proper Potting and Hydration
The choice of potting medium is important, as geraniums are highly sensitive to waterlogged conditions. They require a coarse, well-draining soil mix that allows excess moisture to escape quickly. A standard houseplant potting mix amended with materials like perlite or coarse sand is an effective combination to ensure proper aeration around the roots. The container must have functional drainage holes, which are necessary to prevent standing water from accumulating at the base of the pot.
The routine for hydration should follow a “soak and dry” principle to prevent the most common issue of indoor cultivation: root rot. Before watering, check the soil depth by inserting a finger; only water when the top one to two inches of the potting mix feel completely dry to the touch. When you do water, soak the medium thoroughly until water flows freely from the drainage holes. Discard any water collected in the saucer after about 15 minutes to ensure the entire root ball is moistened while preventing the roots from sitting in saturated soil.
Geraniums require less fertilizer indoors than they do when actively growing outside. During the spring and summer active growth period, feed the plant lightly every four to six weeks using a balanced liquid fertilizer. If the plant is being kept in lower light conditions, or during the winter months, cease fertilization entirely. Over-fertilizing, especially in reduced light, can lead to weak, excessive foliage growth at the expense of developing blooms.
Sustaining Geranium Health
Ongoing maintenance is required to encourage the plant to maintain a compact shape and continue producing flowers indoors. Regular deadheading—the removal of spent flower heads and their entire stalks—redirects the plant’s energy away from seed production and toward developing new blooms. To promote a bushier, less leggy structure, pinch back the growing tips of the stems just above a leaf node.
When the plant is moved indoors, it becomes more susceptible to sap-sucking insects like aphids, spider mites, and whiteflies. Regular inspection of the undersides of the leaves is the best preventive measure for these pests. Should an infestation occur, a gentle treatment with horticultural soap or neem oil is effective, or a strong jet of water can dislodge many of the pests.
If the Pelargonium is being overwintered, its care routine should shift to accommodate a period of reduced activity. During this time, the plant needs minimal water—just enough to keep the stems from shriveling—and no fertilizer is needed. Keeping the plant in a cooler spot, ideally around 50°F, helps induce a semi-dormant state, allowing it to rest and prepare for robust growth once temperatures and light increase in the spring.