Humidity question
 

Hello everyone. I am wondering how much humidity to keep in my orchid growing room, I grow them in the house so I want to know what is high enough for good growth without keeping it too high to damage the house. What would be the ideal percent to use in the house? Does 55-60% sound good? Will this percentage damage the room? Thanks

Jeremy

My orchids growing in a bay window experience normal indoors humidity year round - nothing special. During winter (central heating) they get 30-40% humidity - whatever the furnace creates as it dries out the air. In summer when the windows are open, it might get to 60% on a wet day. All are doing well so far. Might be a bit dry for a couple (like Sedirea) but vegetative growth is nice and green.

My scientific background (and picky, stickler-for-details attitude) are forcing me to pick on you again, Ross.

Heaters to not dry the air out. To do so, there would be some sort of water removal process, and there is none. Air conditioners do dry the air - that's what the condensation is. If you use an exposed-flame heater, water is a fuel combustion product, so it actually increases the humidity.

What we see happening is that in winter, the ambient (outdoor) absolute humidity level is typically lower, because cold air can dissolve less water than warm air. Now you bring that drier air into the house and heat it, and the relative humidity is lower.

The net effect, of course, is the same - dry air - and your response is dead-on.

:bowing :bowing :bowing

Yep. I have one of the "high efficiency" furnaces that pulls the water from the combustion process and pumps it down the drain. In addition the outside air is brought directly to to combustion chamber and what's left of the exhaust is pumped with a fan to the outside. The only moisture introduced to the inside air is from doing dishes, evaporation from buckets and plants, cooking, etc. I was trying to be simple with my reply. I am on your side, but the point is still the humidity levels are dependent on the processes going on within my house - not some supplemental system (which would be pretty ineffective in my case.) Now the terrarium is a different case :biggrin:

I finally got a humidty tester and found mine to be 50% in the kitchen on a regular basis, my humidifer can bump that up 10-15% if I turn it on. Im just happy that the orchids are happy. Jeremy how long have you had these plants in there? Are they under a light?

My orchids have been in there for a long time on a western windowsill, usually the humidity levels stay 65-75% during the winter and 80-90% in the summer by using a humidifier. The plant grew nicely, but this unusally cold winter I found condensation marks on the walls, so I had to lower humidity. Next winter I will probably lower the humidity to 50-55%. I know that this is level is good enough for orchids but is this level safe enough to prevent condensation on the walls (I don't want mold growing in the walls)? Thanks

Jeremy

I maintained 70-75% this winter. I'm curious to see how much it dries out this summer.

I am worried about that level of humidity if yours is not a new house. Older houses do not have moisture barrier plastic in walls and windows will rot out quickly due to condensation. I've been there, and can testify to the truth of this. Newer houses have moisture barriers in walls to lessen the effects, but the windows may still be a problem.

I try to keep mine between 50 and 60%. I use an Air-O-Swiss humidifier when the level is below 50%.

My house was built in 1996. I don't have any idea whether it has moisture barrier. When did they start installing moisture barriers?

Jeremy