Capillary Evaporation

[alexgadd]

Hi

Can anyone provide a layman's description of Capillary Evaporation? I have read it in various gardening books and am at a complete lose.

Thanks

Alex

[Cutecumber]

I am not sure in what context you are reading about it, exactly, but...

capillary action is a process by which plants cells move water (and other substances) upwards from their roots and out to their leaves, where it evaporates (by way of wind and temperature difference). When evaporation is greater than the input of water, plants can wilt.

Is that any good?

[SimonCole]

Good definition.

[rustylady]

The good thing about capillary action (as described beautifully above) is that plants in pots can be stood either on capillary matting or in shallow trays of water and can draw up what moisture they need. This avoids getting the whole pot so wet that the roots rot.

[JennieAtkinson]

That reminds me - I've been meaning to ask for ages. How wet do you keep the capillary matting? If it is just damp, is that enough for the water to seep up?

I've been bottom watering this year (not with matting though) just plants standing in a tray, but the bottom is soggy with water and the tops completely dry. Would using the matting have helped.

Sorry Alex to hijack your thread!

[Peter]

Capilliary action.
Water has surface tension, that is what holds it in drops, as in on a freshly waxed car. The molecules of water on the outside of the water stick to each other stronger than they do to air.
Look at water in a very clean straight sided glass after it has been allowed to settle. it will be
| |
|\__/ |
| |
|____|

Bad drawing, sorry.

The surface tension draws the edge of the water surface slightly up the side of the glass.

Now imagine the glass being much much thinner (diameter smaller) and like a hosepipe.
Then the surface tension of the water can effectively pull the water along the length of the pipe or some sizable portion thereof.

That is capilliary tubing using capilliary action to draw water to your plants from the water reservoir.

Does that answer the question?

[yoanbob]

capillary action. put a drinking straw in a glass of water, the water leval in the straw will always be above that of the glass, due to afore mentioned action. not sure what capillary evaperation is tho, but it must be the evaperation from leaves in hot weather is greater than capillary action, must'nt it?

[alexgadd]

I will dig out the book I read it in and try and put into context but all of the above (or below depending on how you have your settings) makes sense to me, it was just being mentioned over and over assuming that everybody knew what they were referring to, and I didn't!!

Thanks all

Alex