From a botanical perspective, Impatiens walleriana and its relatives are classified as tender perennials. This means their genetic programming allows for a multi-year life cycle, but they lack the cellular adaptations to survive freezing temperatures. Their succulent stems and high water content make them extremely vulnerable to frost, which causes ice crystals to form within their cells, leading to irreversible damage and cell death. Therefore, the winter season in temperate climates is a direct threat to their survival. Bringing them indoors is an artificial intervention that replicates the perpetual warm, frost-free conditions of their native tropical habitats in Eastern Africa, allowing them to bypass this lethal environmental challenge.
A sudden shift from an outdoor to an indoor environment is a significant shock to the plant's system. To maximize success, a gradual acclimatization process is crucial. Approximately two weeks before the first anticipated frost, you should begin preparing the plant. Start by pruning it back by about one-third to one-half of its size. This reduces the overall mass the root system must support and encourages bushier growth later. Simultaneously, it is essential to address any pests. A thorough inspection of the leaves (both topsides and undersides) and stems should be conducted. Treating the plant with a horticultural oil or insecticidal soap spray outdoors will eliminate common hitchhikers like aphids, spider mites, and whiteflies, preventing them from becoming an indoor infestation.
Once indoors, the plant's health depends on how well you can approximate its preferred conditions. Light is the most critical factor. Impatiens will require a very bright location, such as a south or east-facing windowsill, where they can receive several hours of indirect but bright light daily. Without sufficient light, the plant will become etiolated—growing tall, spindly, and weak as it stretches for a light source. Temperature-wise, a consistent room temperature between 65-75°F (18-24°C) is ideal. Crucially, keep the plant away from both cold drafts from windows and hot, drying air from heating vents or radiators, as these extreme fluctuations cause stress.
The plant's metabolism will slow down considerably due to lower light levels indoors compared to the summer sun. This semi-dormant state means its water and nutrient requirements will be vastly reduced. Overwatering is the fastest way to kill an indoor impatiens, as cool, soggy soil leads to root rot. Water only when the top inch of soil feels dry to the touch, and ensure the pot has excellent drainage. You should also cease all fertilization during the winter months; the plant is not actively growing and cannot use the nutrients, which would instead accumulate in the soil and potentially harm the roots. Resume a half-strength fertilizer regimen only when you see signs of new growth in the spring.
