Geraniums (Pelargoniums) are popular flowering plants often grown in containers. Though perennial in warmer regions, they are typically grown as annuals in many climates due to their tender nature. Successfully growing these plants in a pot requires creating the right environment and maintaining a consistent care routine. This guide provides practical steps and detailed insights to help achieve a flourishing display of potted geraniums throughout the growing season.
Setting Up the Ideal Habitat
Geraniums thrive when they receive ample sunlight, ideally needing at least six hours of direct sun exposure daily to produce a wealth of flowers. Placing the container in a spot that receives full sun encourages dense growth and prevents the plant from becoming “leggy,” which is characterized by long, sparse stems. However, in regions with extremely intense summer heat, a location that offers protection from the harsh afternoon sun can prevent the plant from slowing its flower production.
The choice of potting medium directly influences the plant’s health, as geraniums are highly sensitive to standing water. The substrate must be well-draining, which means avoiding heavy garden soil that compacts easily in a container. A high-quality, light and airy commercial potting mix is recommended, possibly amended with perlite or coarse sand to further enhance drainage. Geraniums prefer a slightly acidic to neutral soil pH, generally ranging from 6.0 to 6.5.
When selecting a container, ensuring it has adequate drainage holes is non-negotiable for preventing root rot. Terracotta pots are a popular choice because their porous nature allows excess moisture to evaporate through the sides, helping the soil dry out faster. Conversely, plastic or glazed ceramic pots retain moisture longer, which can be beneficial in arid climates but requires more cautious watering in humid or cooler conditions. Geraniums also tend to bloom better when their roots are slightly confined, so avoiding an excessively large pot is beneficial.
Mastering the Watering and Feeding Schedule
The most common mistake in geranium care involves overwatering, as these plants prefer to be kept slightly dry rather than consistently saturated. A reliable method is the “finger test,” where you check the soil moisture by inserting a finger about one or two inches deep into the pot. Watering should only occur when the soil feels dry at this depth.
When you do water, soak the container thoroughly until excess liquid flows freely from the drainage holes, then be sure to empty the saucer immediately afterward. Allowing the pot to sit in drained water will lead to waterlogged conditions, which can quickly cause the roots to rot. Watering early in the day is advised, as it allows any accidental moisture on the leaves and flowers to evaporate before nightfall, reducing the risk of fungal diseases.
During the active growing season from spring through fall, container-grown geraniums require regular feeding to support their continuous bloom cycle. Unlike garden soil, potting mixes offer limited nutrients, which are rapidly depleted by frequent watering and plant growth.
A balanced, water-soluble fertilizer with an NPK ratio such as 15-15-15 or 20-20-20 is effective for general health. Many growers switch to a fertilizer higher in phosphorus, like 15-30-15, once the main flowering season begins to encourage more blooms. Apply the liquid feed according to the manufacturer’s instructions, typically every two to four weeks during the summer months. Over-fertilizing can lead to excessive foliage growth at the expense of flowers, so it is often better to use a slightly weaker solution than recommended.
Keeping Your Geranium Healthy
Active grooming of the plant, known as deadheading, is important for promoting continuous flowering and maintaining an attractive appearance. This process involves removing the spent flower heads before the plant directs its energy toward producing seeds. When deadheading, follow the flower stem down to the nearest leaf node or main stem and snap it off cleanly by hand or with sharp snips.
Removing the entire stalk, rather than just the faded petals, prevents an unsightly brown stub from remaining and encourages the plant to generate new blooms more quickly. Regularly removing yellowing or damaged leaves also improves air circulation around the plant, which helps to minimize the potential for disease. Checking the plants weekly for these spent blooms ensures a tidy and productive display throughout the season.
Pruning is necessary to prevent the geranium from developing a sparse, “leggy” structure and to encourage a bushier, more compact shape. When a stem becomes long and thin, pinch back the growing tip or cut the stem back to a healthy set of leaves or a node. This action forces the plant to divert growth hormones to dormant buds lower on the stem, resulting in branching.
Common issues for potted geraniums include sap-sucking pests like aphids and whiteflies, which tend to congregate on the undersides of leaves. Minor infestations can often be managed with a strong jet of water or the application of horticultural soap spray, ensuring coverage on the entire plant surface. A common fungal problem is Botrytis, or gray mold, which appears as fuzzy gray patches on fading flowers or damaged tissue. Since this mold results from poor air circulation and excessive moisture, removing dead material and improving ventilation are the best preventative measures.