Aerial Roots of Phalaenopsis: The Ins and Outs of Dry vs. Wet, and What Causes Them to Dry Out

Anyone who grows Phalaenopsis orchids is surely impressed by those few aerial roots sticking out of the potting medium -- either wrinkled like sun-dried preserved mustard greens, or plump like a sea cucumber full of water. So should these things be dry or wet? And if they dry out, how do you save them?

Actually, the aerial roots of Phalaenopsis can't be too dry, nor should they be wet all the time; they need to be in that "moist but not dripping" state. Look closely at healthy aerial roots: the silvery-white outer layer is plump, feels a bit springy to the touch, and up close you can even see a hint of green showing through inside. That's the right state -- they can breathe fresh air and absorb moisture from the air at the same time.

If the aerial roots are dry as firewood sticks, then you're in trouble. So why do aerial roots dry out? A few common reasons: the most direct one is watering too little, or only watering the surface without soaking through. Phalaenopsis roots are fleshy and have limited water storage capacity; in summer, go three or four days without watering and the aerial roots may wilt from dryness. Another cause is air humidity being too low, especially in air-conditioned rooms where the air is like a desert -- the moisture in the aerial roots gets sucked out, so of course they shrivel.

Also, too intense light can bake the aerial roots dry. Last summer I put my Phalaenopsis on the south balcony, and the midday sun beat straight down on it; within two days the aerial roots were scorched gray and hot to the touch. I quickly moved it to a spot with indirect light and misted around it every day, and it took half a month to recover.

There's another easily overlooked cause: the potting medium in the pot has become compacted. Water poured in can't seep through, the aerial roots can't get any moisture, and over time they slowly dry out. Growing in pure sphagnum moss, which balances water retention and air permeability well, rarely causes problems with aerial roots.

If you find the aerial roots have dried out, don't panic -- there's still hope if you act fast. First cut off the roots that are too dry, then mist the surrounding area, not directly on the roots, and let the air humidity gradually come up. Placement matters too: keep it away from air-conditioning vents and radiators, and it's best to put a shallow dish of water nearby so the moisture slowly evaporates.

Aerial roots are the Phalaenopsis's "breathing organs"; you need to give them fresh air without letting them go thirsty. Once you understand this pattern, your Phalaenopsis will surely grow vigorously, with plump white aerial roots and even more vigorous blooming. If you also grow Phalaenopsis, why not go check its aerial roots right now -- are they in a comfortable state?