Geraniums are tender perennials often grown as annuals in cooler climates. To preserve these plants across the winter, gardeners often force them into a state of indoor dormancy. Successfully transitioning them back to active growth requires precise timing and careful steps to ensure a healthy, robust spring and summer bloom display. This guide details the process for safely reviving your geraniums from their winter slumber.
Determining the Ideal Timing for Wake-Up
The correct time to begin the revival process is based on future outdoor conditions, not the current weather. Gardeners should initiate the wake-up period approximately six to eight weeks before the region’s last expected spring frost date. This lead time provides sufficient duration for the plant to resume active growth indoors before it is safe to move it outside permanently.
A natural signal for the plant is the increasing photoperiod, or the length of daylight hours. Beginning the process in late January to early March, depending on your local climate, allows the plant to benefit from improving light conditions as it starts to grow. This timing ensures the geranium is strong and established when the risk of frost passes.
The Initial Wake-Up Process
To end dormancy, relocate the plants from their dark, cool storage area to a brighter, warmer environment. A temperature range between 50°F and 60°F is ideal for encouraging initial growth while preventing the plants from becoming overly leggy. This contrast in light and temperature signals the plant’s metabolism to shift from resting to active growth.
Upon retrieval, inspection is necessary to check for signs of mold, rot, or overwintering pests on the stems and roots. Any shriveled, mushy, or diseased sections of the plant should be pruned away using clean, sharp tools. For bare-root geraniums, rehydration can be accelerated by soaking the roots in water for one to eight hours before repotting.
If the geraniums were stored bare-root, pot them using fresh, pre-moistened potting mix with good drainage. The initial watering should be light, without oversaturating the newly potted roots. If the plants were stored in pots, a light initial watering will suffice to begin the growth cycle.
Essential Post-Dormancy Care and Pruning
Once the geraniums are potted and placed in a bright location, the focus shifts to encouraging strong, branched growth. Strong pruning at this stage is beneficial, as it removes the spindly, leggy growth. Cutting the stems back by up to two-thirds encourages the plant to produce new, bushy side shoots.
Fertilization should not occur immediately, as the plant needs time to establish new roots and foliage. Only after new leaves are emerging should you begin a feeding schedule. Start with a balanced, liquid fertilizer diluted to half or quarter strength to avoid shocking the newly awakened plant.
As the plant’s growth accelerates and new leaves develop, the frequency and volume of watering must increase. The goal is to keep the soil consistently moist but never waterlogged, allowing the top inch of soil to dry out slightly between waterings. Regular turning of the pots will ensure the new growth develops evenly toward the light source.
Hardening Off and Moving Geraniums Outdoors
The final stage before permanent outdoor placement is known as hardening off. Plants that have spent months indoors are sensitive to intense sunlight, wind, and temperature fluctuations and must be introduced to outdoor conditions slowly. This process typically takes seven to ten days to complete safely.
Begin by placing the geraniums outside in a shaded, sheltered area for one to two hours per day. Each day, slightly increase the duration of their time outdoors and gradually expose them to more direct sun and wind. This slow transition allows the plant’s cell structure to strengthen and its tender new foliage to adapt to ultraviolet light, preventing sun scald.
The plants can be moved to their final outdoor location only when the danger of all spring frost has passed. Wait until nighttime temperatures consistently remain above 50°F. Placing geraniums outdoors too early, even during warm days, risks cold-induced stress or death from unexpected late-season frost.