An important factor in determining the suitability of a plant to your home and envisioning the care it will need, is to know the origin of the plant. Plants that are native to desert regions will require substantial amount of sunlight and loose, fast-draining soil. Plants from the floor of a rainforest will need some protection from strong sunlight and generous humidity.
Tillandsia varieties sold as houseplants are epiphytic or lithophytic bromeliads from varied habitats. Like most bromeliads, they are resilient and adaptable. Native to the southern United States, Central and South America, these plants have a limited root system and would, in their natural habitats, receive water and nutrition from the air around them through specially-adapted, scaly structures on their leaves.
If you are not sure about the native habitat of your air plant, you should ask the at the shop where you make your purchase. Alternatively, you can make a good guess based on the color and texture of most common air plants. An air plant from a humid, tropical habitat will be darker green, less scaly (or hairy) and is likely to have curved leaf structures. Air plants with silver-green, scaly (or fuzzy) and flatter leaves are probably from a dry environment. There are also air plants that fall in between, with light green, slightly fuzzy leaves or characteristics from both ends of the spectrum.
Air plants can be grown in windows or under fluorescent light. They thrive in bright, filtered sunlight, during the growing season (April to October) but can be scorched if exposed to strong, direct sun. During the rest of the year, they are happy in more direct sunlight.
If your plant is from a tropical habitat, it will need greater protection from light; a dry climate Tillandsia is tolerant of greater, direct sunlight.
Fluorescent light is not as strong as sunlight and the plant will need twelve hours of artificial light, at a distance of no greater than two feet, per day. Plants grown under artificial light tend to need more water than those grown with natural light.
Most air plants have very limited root systems and absorb water through their leaves. Water them once or twice per week by immersion in tepid water. If you have an air plant from a dry region (with silver, fuzzy leaves), you can dunk the plant rather than soaking it as it needs less water. Greener plants from tropical habitats will need to soak for ten to twenty minutes. Adjust watering to reflect the heat and light conditions of the season and your home. All Tillandsia will rot if over-watered.
Your air plant will survive most successfully if you are also careful about the type of water you use. Distilled water is preferable as tap water will gradually overwhelm your plant with mineral salts. Distilled water will, however, gradually leach nutrients from the plant as it soaks so adding a little fertilizer to the water helps.
Do not allow the plant to remain soggy or sit in a puddle of water. You should let the plant air dry after watering in a spot with good air circulation where it will dry out within four hours. Mist the plant to boost humidity occasionally, but as a supplement not a replacement for watering. A tropical air plant will benefit from the added humidity.
Like most bromeliads, air plants tolerate a broad range of temperatures from near freezing to 100ºF. but are happiest in temperatures that range between 65 to 90ºF during the day and 50 to 65ºF at night. Good air circulation is essential.
Do not grow air plants in soil or on any surface that holds moisture, which can lead to rot. Air plants can be mounted by glue to a supporting surface, suspended, or rested, bare root, anywhere that gives them the light and air circulation that they require. Keep in mind that you will want to be able to submerge your plant regularly to water it.
Air plants are sometimes displayed in small, glass orbs which can help to maintain the humidity. This can be beneficial for tropical air plants. Remember that they also need good air circulation so do not keep air plants in a container with no opening. If you notice significant moisture puddling in the glass container, remove your air plant so that it doesn't rot. Do not place your orb in a position of direct sunlight which can scorch the plant.
A bromeliad fertilizer, or an acidic, general, fertilizer at quarter strength, twice a month and applied with a sprayer, is generally advised. Or add in a lower concentration whenever you water the plant. Avoid fertilizers with boron, copper or zinc which can be damaging to your plant.
Do not rest them or attach them to a substance, like moss, that retains moisture or they may rot.
The most common problems are under-watering, sun scorch or burning with too much fertilizer.