Phalaenopsis and humidity - Orchid Board

EmeraldMistress · #1 01-01-2022, 08:53 PM

I know that aerial roots form in order to suck moisture from the air. My phalaenopsis do not have any aerial roots; when a root formed last spring from the middle of the stem, it grew strait out for a bit and then headed down towards the medium. So I can gather that my house is probably just not humid enough to warrant the plants growing aerial roots. Is that ok? Is that a bad sign, should I look into a humidifier for the room I grow them in? Oh! And while I have you here, when I was first growing I thought I read that they wanted a north facing window, but I recently read on here that they want an east facing window? Can someone clarify which one they want, and how important it is? Unfortunately I don’t have a good east facing window I can use :/

Roberta · #2 01-01-2022, 09:06 PM

Your Phal sounds fine to me. Often they'll do aerial roots when the medium is wet and airless. If they're growing into the medium, GREAT! The balance of air and moisture in the pot is very good!. As for the direction of the window, I don't think it makes much difference. The goal is indirect light (since these are low light plants) and either direction will work fine. In fact, you may also want to supplement the hours of light with an LED or fluorescent lamp...the short days of winter may not give it the duration of light that it needs to bloom. At least that was my experience... I went from little reblooming to nearly 80% by adding a light on a timer, 12 hours a day. So if it grows but doesn't bloom, something to consider.

Shadeflower · #3 01-01-2022, 09:07 PM

It depends who you ask but I do not see a difference between an aerial root and a regular root. An aerial root is a regular root that grows into the air. It's debatable how much moisture aerial roots can suck from air. I don't think much. A root, whether aerial or not will want to suck moisture from its surroundings. Eventually most of the time when an aerial root does not hit any moisture it stops growing. Only in a really humid environment or if an aerial root hits moisture will it carry on. so there is nothing wrong with a root going into the pot. With a phal its the most practical way to water it.

EmeraldMistress · #4 01-01-2022, 09:15 PM

Quote:

Originally Posted by Roberta

Your Phal sounds fine to me. Often they'll do aerial roots when the medium is wet and airless. If they're growing into the medium, GREAT! The balance of air and moisture in the pot is very good!. As for the direction of the window, I don't think it makes much difference. The goal is indirect light (since these are low light plants) and either direction will work fine. In fact, you may also want to supplement the hours of light with an LED or fluorescent lamp...the short days of winter may not give it the duration of light that it needs to bloom. At least that was my experience... I went from little reblooming to nearly 80% by adding a light on a timer, 12 hours a day. So if it grows but doesn't bloom, something to consider.

Thank you very much! I have one blooming now, and another is a grocery store clearance I rescued a few months ago, so I don’t expect to see it bloom until next fall. If it doesn’t bloom next fall and/or if the other one fails to bloom next year then I’ll definitely look into lights for them.

---------- Post added at 08:15 PM ---------- Previous post was at 08:12 PM ----------

Quote:

Originally Posted by Shadeflower

It depends who you ask but I do not see a difference between an aerial root and a regular root. An aerial root is a regular root that grows into the air. It's debatable how much moisture aerial roots can suck from air. I don't think much. A root, whether aerial or not will want to suck moisture from its surroundings. Eventually most of the time when an aerial root does not hit any moisture it stops growing. Only in a really humid environment or if an aerial root hits moisture will it carry on. so there is nothing wrong with a root going into the pot. With a phal its the most practical way to water it.

That’s a good point about the aerial roots not growing if there’s not enough moisture; when I got my first phal a year ago it had a huge twisty, beefy, aerial root. But within the first few months it shriveled up and got flat and papery. I eventually cut it off. So apparently the store I got it from (or the nursery it was in before that) was super humid and then when I brought it home there just wasn’t enough to support that root anymore so it died. But it seems happy regardless!

estación seca · #5 01-01-2022, 09:51 PM

Not many Phals grown in centrally heated homes have huge, healthy exposed roots. This is not a problem. When those plants are moved into higher humidity (perhaps 60%) they will grow large, exposed roots.

TZ-Someplace · #6 01-02-2022, 10:34 AM

A root cannot pull moisture from the air. Even "air plants" do not pull moisture from the air. It is physically impossible under the conditions we are talking about. They get wet when it rains and absorb water then. They need to stay wet for a fairly long period of time to do any good. Simply misting them doesn't do much when the water evaporates quickly. In a counter top situation I generally view aerial roots as a waste of growth resources better put into leaves or pot roots, and I do cut them off to stop growth when they start heading that way because I water and fertilize in the pot.

Most of the orchids I have grown have been under low humidity or high evaporation conditions (California desert apartment, Midwest winter heating, high summer greenhouse temps without a misting system or temperature control). The base of the plant and the roots like high humidity to grow roots, but that is the job of the potting medium, not the room air.

The window that does not fry the plant is the window the plant likes. East gets cool morning light with much of the hotter red-infrared wavelengths filtered out from higher moisture in the over night air, and it has lower damaging ultraviolet. Southern has too much intensity, West is hot and higher UV. Air movement from a fan will help keep damaging leaf temperatures from rising in late morning for east, and early afternoon for west.

For a north window and a bad east window I would make sure to put reflective material under and behind the plants to boost the light that hits them. Crinkled up and flattened aluminum foil is one of the better materials to use. White materials (plastics, painted surfaces) tend to let a lot of light penetrate through them unless specially made for the purpose.

Arizona Jeanie · #7 01-02-2022, 12:33 PM

My growing conditions are exceedingly dry, with very little humidity in the air. I was quite surprised to discover that Phalaenopsis orchids do just fine, in fact are one of my more successful houseplants.
They regularly send out some aerial roots. I don't think they're trying to absorb water, there's none to be had in this air. I think it's more part of the plant's natural search for a secure anchor. It doesn't really "know" that it's in a pot, it came from a very long line of epiphytic ancestors.
I enjoy seeing the aerial roots, and wouldn't dream of cutting them off. They are green, and add some photosynthesis capability. Plus, any time you make a cut you are opening a wound that is susceptible to bacterial, fungal, or viral infection.
The only times I've seen excessive aerial roots is when the roots in the pot are in trouble, also just above an area of stem rot. They are a symptom of the problem, not a cause.
Try browsing a bit in the "Root Porn!!" section of the Advanced Discussion forum, lots and lots of amazing pictures of aerial roots.