White orchids come in many varietals, from phalaenopsis and dendrobium to paphiopedalum. Among the many thousands of varietals of orchids, their care can vary somewhat, differing in terms such as how much light they prefer, what they should be planted in, and precisely how much moisture they require. However, basic principles of orchid care remain constant and will keep your white orchid in bloom as long as possible while maintaining a healthy plant overall.
Place your white orchid plant is a setting with indirect light ranging anywhere from bright to dim. Keeping your white orchid in lower light conditions during bloom can extend the life of the bloom. But if you keep your orchid in a room that has no light during most of the day, such as a windowless bedroom or bathroom, it will suffer. Rotating the plant into lighted conditions every other day or so will help preserve its life cycle somewhat.
Water your orchid by drenching it every 7 to 10 days, allowing the planting medium to dry out a bit before watering again. In dry climates or when air conditioning or heaters are in use, more frequent watering may be required. In addition, you can spray your orchid with clean, tepid water once a day and assemble a humidity tray under it to raise the humidity in its immediate vicinity. Select a saucer or tray and fill with small stones and water. Place the orchid pot on top of the tray and replenish the water frequently enough to keep it full.
Fertilize your white orchid with a diluted orchid food once per month, according to the package directions. Pour the fertilizer and water solution through the plant after it has already been watered and the planting medium is wet, and allow the excess fertilizer solution to drain away. This will prevent burn to the roots and accelerate the uptake of nutrients by the plant.
Cut back the white bloom stalk after the flower has faded and the entire stem has withered and died back. Allowing the nutrients held in the stem to fall back into the plant provides an energy boost for the plant, which will help it recover from blooming and prepare for the next cycle. Allow the leaves to die back on the plant naturally, and only remove them when they come loose with the gentlest of pulling. This will protect the stem from damage and prevent the invitation of disease.