mysterious powdery dust throughout greenhouse - Orchid Board

sevilliana · #1 12-31-2009, 06:16 PM

I have noticed a very fine powdery white dust on my orchids - many different varieties. It is so fine it is almost like a mist. when I remove it with my fingers it looks and feels like face powder. It is softer/finer than that associated with mites. The only change in my greenhouse is the addition of a hydrofogger that I now run 24 hours and which is controlled by a humidistat.

Any ideas what this could be and how to get rid of it? Many thanks

Blueszz · #2 12-31-2009, 06:31 PM

Do you use tap water for the fogger? Does it produce tiny droplets of water that evaporate (instead of heating water to steam)? In that case your plants probably are covered with calcium deposits...

Nicole

ronaldhanko · #3 12-31-2009, 07:56 PM

I second Nicole on this one.

PaphMadMan · #4 12-31-2009, 08:49 PM

Make that 3 votes. Definitely some kind of mineral dust from your fogger, whatever is in the source water.

Gin · #5 12-31-2009, 09:16 PM

Make that 4 ... I have an under bench mist hose fed with tap off and on the fan will blow it on a leaf. The high pressure mist pump is fed with rain water because of the deposits .. Gin

sevilliana · #6 01-01-2010, 10:33 AM

I use tap water. It sounds like you all are right - The humidifier feeds directly from our household plumbing. Can I do anything about it? I don't think I can set up a rainwater feed. Does the calcium hurt my plants? Many thanks to all and Happy New Year.

Gin · #7 01-01-2010, 11:35 AM

I would check out some type of filter to get rid of the lime in the feed at least reduce it . In time the deposits will build up on leaves drying them . I have a few that still have deposits from our well water before we moved a few years ago . I can't run the fogger much it really sucks the rain water out of a big trash can in the green house . If you find something that will work let me know .. Gin

PaphMadMan · #8 01-01-2010, 11:45 AM

Quote:

Originally Posted by sevilliana

I use tap water. It sounds like you all are right - The humidifier feeds directly from our household plumbing. Can I do anything about it? I don't think I can set up a rainwater feed. Does the calcium hurt my plants? Many thanks to all and Happy New Year.

Tap water might contain magnesium and iron, some other elements in addition to calcium - most likely as carbonates. Unless your water goes through a softener, then the calcium etc. is replaced with sodium, even worse for your plants. You might want to consider an RO system to remove all minerals from your water.

Ray · #9 01-01-2010, 12:41 PM

I feed my hydrofogger with RO - no problem whatsoever.