Orchid Leaf water absorption - Orchid Board

PapaPhal · #1 02-09-2013, 04:22 PM

I have what maybe a stupid question but I think I get a reprieve because I am in the beginners’ forum.

I am not sure if this is significant or not but every time I mist my plants, particularly the phals, I notice that some of the leaves repel the water; it beads up and evaporates off, and others apparently absorb the water because the water is gone a lot faster. The leaves that repel the water look shiny whereas the leaves that absorb the water look dull. Kind of like the difference between flat and gloss paint. I am guessing that this common but I am not sure. Thanks for your input.

billc · #2 02-09-2013, 05:23 PM

I've never noticed that although I try not to get too much water on the leaves. I'll try it tomorrow when I water and see what my leaves do.

Bill

PapaPhal · #3 02-09-2013, 05:40 PM

Thanks Bill. Let me say that I know that water should not be allowed to sit in the crown of a phal. If a little gets in there I remove it. If I mist I do it in the morning.

Ray · #4 02-09-2013, 05:59 PM

Orchid leaves are, for the most part, designed to block the transfer of water - in or out. Certainly the transfer is a great deal slower than that of terrestrial plants.

I would bet that the apparent faster drying by the "matte" leaves compared to the glossy ones is merely a matter of physics - the water sits in spherical droplets on those still having a decent waxy coating, ducking the surface area for evaporation, while on those that are easily wetted by the water, it forms a broader film, which having a greater surface area, dries faster.

PapaPhal · #5 02-10-2013, 01:55 AM

I did not realize that orchid leaves do not absorb water. If that is true, I think you are on to something. The water is definately more evenly dispursed when it is applied on the matte leaves so you are correct it would evaporate faster. I just thought it was being absorbed. Thank you for educating me Ray.

billc · #6 02-10-2013, 07:59 AM

After watering this morning, your observation seems to hold true. The glossy leaves seem to have the water beading up like water on a newly waxed car. The matte leaves don't seem to have as much beading.
I also realized I soak my mounted plants leaves every morning. So much for what you think you're doing.

Ray's explanation seems logical to me.

Bill

Ray · #7 02-10-2013, 08:14 AM

I did not mean to imply that they DON'T absorb water, just that they are designed to resist any water flow through the tissues. They are bound to absorb some, just not much and not quickly.

All of this is part of the evolutionary strategy to conserve water. As the creatures live in trees where they are at the whim of rain and condensing mist for water, rather than a readily available supply in the soil, they must do whatever they can to retain whatever they have.

james mickelso · #8 02-11-2013, 01:49 AM

The top of the leaves don't absorb water readily but the undersides do. That is where the stomata are and they are designed to absorb water and exchange gasses. Orchids without roots can be kept alive by misting or drenching the undersides. The stomata also abosrb nutrient laced water and some nurseries water their orchids with a weak nutrient water. Foliar feeding is the term.