How do Orchid roots actually work? - Orchid Board

cythaenopsis · #1 07-21-2011, 03:01 PM

I've seen photos of orchids in the wild, nestled in the crevices of tree trunks with their roots stretching out in a variety of directions. So when it rains, the water just rolls over those extended roots and falls away. I guess in most cases for a thriving orchid, debris from the trees (like moss) will collect in the crevices and absorb moisture, which will supply water for the roots there. And this is essentially what we're copying, by having our orchids potted with moss and other semi-porous filler. Correct?

So are some of these roots reaching out from the plant not serving to absorb water, but instead intending to help anchor the plant to its surroundings? The exposed roots above and outside the moss don't seem to serve any apparent purpose, with respect to taking in water. Or do they take moisture from the humid air?

tucker85 · #2 07-21-2011, 04:12 PM

There are many people on this board more qualified to answer this question than I am. But I'll get you started. The root that we see is actually the outer covering called the velamen. The cells in the velamen are like a sponge and can absorb the slightest moisture from rain or dew. It can also absorb water vapor from the humidity in the air. So the answer is yes, the aerial roots do serve a purpose.

cythaenopsis · #3 07-21-2011, 11:20 PM

^ Ah, OK. Thank you, Tucker. Well, then going by that, it would seem that misting is a fine thing to do as long as the roots are targeted. I'd been reading a few threads that debunked misting, concluding it as unnecessary. But in the case of exposed roots, the plant would probably appreciate some moisture on them periodically. Would you agree?

tucker85 · #4 07-21-2011, 11:38 PM

It really depends on the orchid and the environment. I mist my phals and my vandas almost every morning but they are outdoors in south Florida and they dry very quickly. I also mist some orchids that are mounted instead of being in pots. Cattleyas and Laelias like to be watered heavily and then get very dry before the next watering. So I seldom mist them. I also use a fungicide once a month because when plants are frequently watered there's always the chance of fungus problems. But you're right, many experienced growers will tell you not to mist orchids. You'll have to figure out what works with your orchids in your environment. Good luck.

glengary54 · #5 07-22-2011, 12:11 AM

I think when people say don't mist them, what they are actually saying is that misting alone is not sufficient in and of it self as a watering mechanism.

King_of_orchid_growing:) · #6 07-22-2011, 12:48 AM

Quote:

Originally Posted by glengary54

I think when people say don't mist them, what they are actually saying is that misting alone is not sufficient in and of it self as a watering mechanism.

Yes, this is part of the reason why people say that misting is unnecessary.

The issue of misting is a bit more complicated however...

As Tucker did say, it is a guideline, not a rule to not mist. There are things to understand and watch out for.

For instance...

Lepanthes spp. or Lepanthopsis spp. can be misted, and these are usually grown indoors or in terrariums/vivariums. The reason why is because they can come from mid to high elevation cloud or mist forests.

Even Phals can be misted - if they're grown how they naturally orient themselves in the wild.

Usually Phals are potted and artificially propped up vertically to grow upright, which is not natural for Phals at all.

The problem when a potted Phal is misted is that:

1. When unsuspecting people grow Phals upright in a pot, and they start misting; the water droplets from the misting can collect inside the crown very easily.

2. They're grown indoors where there is usually not as much air circulation drying up the water droplets that get into the crown. This is a great way to kick start crown rot.

Other orchids are desert growers. Misting is not necessary and can promote rotting.

I think you get the point about misting.

Call_Me_Bob · #7 07-22-2011, 12:48 AM

Quote:

Originally Posted by tucker85

There are many people on this board more qualified to answer this question than I am. But I'll get you started. The root that we see is actually the outer covering called the velamen. The cells in the velamen are like a sponge and can absorb the slightest moisture from rain or dew. It can also absorb water vapor from the humidity in the air. So the answer is yes, the aerial roots do serve a purpose.

thats why some, such as phal roots, turn green.

glengary54 · #8 07-22-2011, 01:27 AM

Philip - I totally agree with you that there are plants, such as those from the montane forrests, where misting is an acceptable means of watering and raising the humidity to a level that they are used to. Unfortunately, in todays market there are so many people selling orchids who haven't the slightest clue as to how to grow them, who are giving out bad culture advice. From my experiences with new/novice growers, their first exposure to orchids is usually one of the 4 most commercially popular genera, Catts, Phals, Dens, Oncs,and maybe cymbidiums. Although misting any of these plants won't necessarily harm them, outside of your comments regarding crown rot, it is not the ideal way of watering them.

King_of_orchid_growing:) · #9 07-22-2011, 02:30 AM

I guess I should've clarified that misting is not the most efficient way of watering many orchids.

Misting is mostly a means of an inefficient attempt at reproducing morning or evening mist or dew.

It is also more commonly used as a means to make sure the roots that are dangling in mid-air get some water.

Which brings us back to the original question...

How orchid roots work.

glengary54 · #10 07-22-2011, 02:37 AM

Quote:

Originally Posted by King_of_orchid_growing:)

I guess I should've clarified that misting is not the most efficient way of watering many orchids.

Misting is mostly a means of an inefficient attempt at reproducing morning or evening mist or dew.

It is also more commonly used as a means to make sure the roots that are dangling in mid-air get some water.

Which brings us back to the original question...

How orchid roots work.

Then the simple answer to the question would be, very efficiently.

Goodnight.