Orchids are popular houseplants, prized for their exotic, long-lasting flowers. A healthy orchid life cycle includes a natural resting phase called dormancy. This period is a survival mechanism, allowing the plant to conserve energy and prepare for the next season of growth and flowering. Understanding this pause is important for the plant’s long-term survival and successful reblooming.
Defining Orchid Dormancy
Dormancy in an orchid is a temporary suspension of active growth, not a sign of decline or a dying plant. It involves a reduction in the plant’s metabolic activity, allowing it to reallocate stored energy internally. The roots and leaves remain alive, but the processes of cell division and nutrient uptake slow down.
The most noticeable physical sign of dormancy is the cessation of new growth, particularly the absence of new leaves, roots, or flower spikes. For many common varieties, the loss of flowers signals the end of the blooming cycle and the beginning of the rest period. Deciduous orchid types, such as some Dendrobium species, make this state even more apparent by dropping all of their leaves.
The plant’s structures may also change visibly. Pseudobulbs—the swollen stems that store water and nutrients in orchids like Cattleyas and Oncidiums—may appear firmer or slightly wrinkled as the plant draws on its reserves. This state of stability and conservation is distinct from a plant suffering from root rot or disease, which shows irreversible damage like mushy roots or collapsing tissue.
Seasonal Triggers for Dormancy
The timing of dormancy is governed by the orchid’s native environment and its evolutionary growth cycle. Most orchids that enter a deep rest period are triggered by environmental changes that mimic the dry or cool seasons in their natural habitats. This synchronization ensures the plant is ready to bloom when conditions are optimal.
Two primary environmental cues initiate this resting state: changes in photoperiod and shifts in temperature and hydration. Shorter daylight hours, which occur in the fall and winter months in temperate zones, signal to the orchid that the growing season is ending. This reduction in light intensity is a strong indicator for many species to slow their processes.
Concurrently, a drop in temperature, especially cooler nighttime temperatures, and reduced water availability prompt the plant to enter its rest phase. For many popular sympodial orchids, such as Cattleyas, Oncidiums, and deciduous Dendrobium nobile types, this rest is required and often occurs in the late fall or winter. The rest period can last for several months until the environmental cues for spring growth return.
Not all orchids enter a true dormancy; the popular Phalaenopsis (Moth Orchids) and Paphiopedilum (Slipper Orchids) are exceptions. These monopodial types grow continuously throughout the year, only experiencing slowed growth after flowering. For Phalaenopsis, a temporary drop in nighttime temperature (55°F to 65°F) is often used to trigger a new flower spike, but this is not a deep dormancy like that of deciduous varieties.
Essential Care Requirements During Dormancy
Once an orchid has entered its dormant phase, growers must adjust their care routine. The most common mistake is maintaining the watering schedule used during active growth, which can lead to root rot. Water frequency must be reduced, sometimes to as little as once or twice a month, allowing the potting medium to dry out almost completely.
The purpose of reduced watering is to ensure the roots do not sit in cold, soggy conditions while the plant’s metabolism is slow. Care must be taken not to let the pseudobulbs shrivel excessively, which indicates a need for a slight increase in moisture. This balance prevents both root death from rot and plant death from desiccation.
Fertilization should be stopped entirely for plants in deep dormancy, as the orchid is unable to utilize the nutrients. Continuing to feed a resting plant causes mineral salts to build up in the potting medium, which can burn the roots and inhibit future growth. Only when new growth appears in the spring should a weak fertilizer regimen be reintroduced.
Maintaining appropriate environmental conditions means providing a slightly cooler location, if possible, to reinforce the rest period. While the plant still requires indirect sunlight, the overall light requirement is reduced due to the lack of active growth. Good air circulation is also important to prevent fungal issues from developing in the cooler, less active environment.