You may have seen Tillandsia (Airplants) being sold at plant shops even supermarkets and left with many questions about how Tillandsias work and what their needs are. "Do they just need air?", in short, No...they need a little more...but luckily Tillandsias do not demand much but their care can vary quite a bit depending on which "group" your Tillandsia(s) of choice belongs in.
Quick rundown of what Tillandsias are: Tillandsia is a genus of plant that belongs in the Bromeliaceae family which includes Pineapples, Puya, and Neoregelia. There are several species of Tillandsia that grows terrestrially but those are a vast minority in the genus. Tillandsias produce anchoring root-like structure that grabs onto trees, rocks, cliffs, and more-recently- electric wires and buildings. These anchor "roots" do not actually absorb moisture other plants' roots do, so they are not true roots. Another key feature to Tillandsias would be the trichome on their leaves. Trichomes are little fuzzy whitish, silverish hairs on their leaves that helps them catch moisture from the air (i.e. fog and rain). Most Tillandsias are monocarpic (they die after they flower) but they will also produce pups as they go into decline post-bloom; producing 1-5 new growth.
Now that we know what Tillandsia generally are, let's get a little bit more detailed. This would be the important part for their success.
Tillandsias can be found in tropical, grasslands, savannah, cloud forests, deserts...They can be found in many environment. We (at The Other Side Nursery) like to think of them as being in three different groups: Tropical (including cloud forests), Savannah (including grasslands, and rocky outcrops and openings) and Arid (desert).
Tropical Group: This group is from the wetter parts of the world. Tillandsias here are generally lacks obvious trichomes so their appearance is smoother, somewhat thick and plastic-y and they are generally greener/dark green. Tropical species do not have much trichome because they rely on a steady supply of rain that they get from the forest; it is also a lot more humid so they adapt to wicking water off- as opposed to trying to catch water. Light requirement for this group is also on the lower end, generally in their native habitat they will get dappled light.
Example species: butzii, bulbosa, fasciculata
Water: Mist/run under tap about twice a week. Shake off excess water!
Light: Morning sun, very late afternoon sun, dappled sun
Savannah Group: This group of Tillandsia are from open areas with little trees, if there are lots of trees it is still very open where the sun can still be fairly bright. This group of Tillandsia are generally broader-leaved with visible-but-still-small trichome. Generally this group looks a little more sage-green, light green (but this can vary a lot so leaf color in this group is not helpful in helping with the identification). This group will tolerate more exposure to the sun than tropical species, and will appreciate it. This is the "when in doubt, treat them like this" group since most of the Tillandsias will be in this group. Tropical and Arid Tillandsias can tolerate Savannah conditions.
Example species: xerographica, ionantha, ehlersiana
Water: Mist once a week. Shake off excess water!
Light: ~3-5 hours of morning sun, dappled sun all day.
Arid Group: This group of Tillandsias can be found where water is scarce and sun is plenty. Many plants in this group can look very fuzzy due to the high amount of long trichomes to catch morning fog; they will generally be a lot more silvery/white (with trichome) to help them reflect away some sun. Generally, this group of Tillandsia produces wiry, stringy leaves. This group is more for advanced collectors but it is still possible to be successful as a beginner.
Example species: tectorum, exserta, landbeckii
Water: Mist [only] once a week - once every 2 weeks. Shake off excess water!
Light: 5+ hours of direct sun, best to start from morning.
Mounting: You can display Tillandsias by simply leaving them on a surface, suspending them with strings, or in an open vessel or you can hot glue or use E6000 glue to attach them to surfaces! It is best to adhere them using their anchor roots and their base instead of using their leaves because old leaves will eventually fall off, dislodging the plant. Try not to cover the base of your plant, it can promote rot.
Flowering stage: When your plant starts to flower you will start seeing different shades of colored leaves in the center of your plant where the new growth usually forms; the colors can look completely different than what you've seen before on your plant such as reds and purples and yellows. During this time your plant will get ready to produce new side growth/pups so it is important to take extra care to make sure that it is healthy enough to spend energy on producing pups. The main part that flowered will decline after a couple of months but by that time, ideally, you should have new pups that grew in.
Fertilizing - Use quarter-strength water soluble all purpose fertilizer. There are many different views on what to feed what what NPK levels work best, but all purpose should work effectively.
Note on watering: We have encountered many people encouraging soaking Tillandsias, though this is generally alright to do, they would not experience being underwater for long periods of time in the wild...we just prefer misting our plants...it also avoids water-based rot. Shake off excess water! Shake off excess water! Shake off excess water!
*Disclaimer* Plants will react different in every region. Please take into consideration how your regional climate will change the care. (i.e. if you live in a desert, you will need to water your plant more often than if you lived in a tropical zone with constant humidity in the air.)