I haven't tried either of them myself (I grow outside), but from what I understand there are two types of cool mist humidifiers, evaporative and ultrasonic. From the way I see it the evaporative type are basically the same thing as a swamp cooler, and the ultrasonic type are just basically a flogger. And warm water humidifiers humidify by heating the water to a boil (creating a steam). Long story short they both just humidify the room (area). But from what I have read they both can clog easily (if not cleaned often) depending on the type of water your using, not to mention if you plan to put anything in it as a foliage spray. Not sure what the cost difference is though.

Hi Mike,
You could try it but i`d say the mist droplet size is too small to be effective. You`ll likely end up running it for ages so the small droplets colesce into larger ones on the root surfaces.
The roots won`t be using the mist directly which is what you want, they`ll be using the water after it reverts back to liquid so you might as well use nft or ebb and flow..it`ll be cheaper and will give you the same results.

Was this question for air (foliage) or roots?

You`ve got me wondering now. The thread title says "growing", so presumably its roots :)

It's for roots. I didn't think it would work but figured I might as well ask!

Mike

I was reading
" 9 gallons of mist into the air per day"

So I was thinking in terms of air/foliage. I don't have experience with them myself but depending on the partial size etc. I would probably agree with hex. But for me a lot would be riding on how much it costs. If it cost more than a regular (inexpensive) ultrasonic fogger, I doubt I would try it, unless it was given to me to try.

I hope it's not a faux pax to bump old threads.

Ultrasonic misters are used in aeroponics. For example, it is covered in Keith Roberto's How To Hydroponics book, and on his website he links to commercial transducers specifically designed for hydro. I think the upshot is that this is still in the experimental phase, and that best results are achieved by a combination approach - ebb-n-flo or a drip system to get the bulk of the nutrients to the plant during growth phases, with the misting system offering massive doses of oxygen, water, and nutrients. The aforementioned book has a photograph of a root with an incredible amount of root hairs. You can find similar pictures if you start googling for ultrasonic hydroponics. I haven't done it myself so I'm not going to mention any specific manufacturer, but they are out there, suggesting that this technique is beginning to reach past the hobby stage.

I like your note on bumping old threads... lol. I find it funny that even adults on many forums get all bent because old posts fuind new light.. I have been venturing into the realm of soiless gardens.. It sounds like the aerponics, misters, etc, can work super efficiently if you can keep the nozzles clean and operating at the peak performance level. But I havent found the right nutrients to use the prevent the buildup of salts..