How to Take Care of Phalaenopsis Orchids

Plant phalaenopsis orchids in plastic pots filled with fir bark, tree fern, peat, perlite, charcoal or a mixture of these. The University of Tennessee's article "Growing Orchids in the Home" recommends three parts fir bark, one part perlite and one part chopped sphagnum moss for phalaenopsis orchids. This mimics their natural habitats, where they attach themselves to trees rather than growing from the ground soil.

Place orchid pots on a tray filled with gravel. Add water to the gravel to produce humidity for the orchids. Alternatively, place the orchids in a bathroom window where they can enjoy the steamy conditions. A humidity of 60 to 70 percent is ideal for phalaenopsis orchids.

Set orchids in an eastern-facing window where they will receive medium light. Protect them from direct sunlight -- especially in the middle of the day -- with a sheer curtain. You may also set them 8 inches beneath four 40-watt fluorescent lights and two 40-watt incandescent lights. While all orchids prefer indirect light to direct light, phalaenopsis orchids prefer low light most of all.

Keep temperatures warm. Phalaenopsis orchids need temperatures of 70 to 85 degrees Fahrenheit during the day, with a 10 degree drop at night to inspire flowering. Keep nighttime temperatures about 60 degrees Fahrenheit during winter, as they can't survive the cold.

Water phalaenopsis orchids when the soil starts to dry. Don't allow them to dry out completely between waterings, as they are unable to store water the way other orchids do.

Fertilize orchids every week during growth and blooming periods with a diluted, equal fertilizer, such as 10-10-10 or 12-12-12. If planted in tree bark, they need more nitrogen -- indicated by the first number in the sequence -- such as 15-5-5. Refrain from fertilizing when they enter dormant periods.

Support orchids with stakes as they grow, if necessary. Replace wooden stakes regularly so they don't rot at the bottom.