Greenhouse humidity problem
 

No matter what I've tried, I cannot get the humidity in my 12'x16' greenhouse much higher than 20% unless it's raining or early morning condensation. I'm trying to figure out some kind of inexpensive fogger system. Does anyone have any suggestions?

I'd recommend fogging systems like MistKing I use one of these and highly recommend it.

Old fashioned technology works great. We bought a folding laundry rack at Wal-Mart and keep it covered with wet towels. Takes our sunroom from 20% to 50% in no time. We re-wet the towels in the morning and again at night. Totally solves our low humidity problems.

Sailor, that's a low tech swamp cooler! Catlady, I'm not sure where you live but our ambient humidity here in NC is about 30% in the winter. If the ground is wet in a greenhouse and it is not completely open I just don't see how it could be that low. Heating is also a factor that can take it lower but I suspect we need allot more information before we can help with the problem.

Greenhouse humidity problem
 

In addition to the humidity, I've been fighting high temps. I live in Brooksville, FL. and the gh, which has the ends east-west and the sides north-south, gets full sun most of the day. I have a 40% or 50% reflective shade cloth over it, and am now adding a 40% or 50% shade cloth inside. This helps with the temp. and cuts down on the light intensity which is now about 6,000 foot candles. If I can get the hunmidity up, the temp will come down, I think. Also, if I cut back more on the amount of light (get it down to 4,000 foot candles like the book recommends, even though it seems awfully dim) that should also help with temp. I have 2-12"fans, 3 louvers (2 of them temp controlled), the 16' long sides can be rolled up to about 4' for additional ventilation. The floor is mulch which I dampen frequently. I'm sure you're right about maybe too much ventilation, but if I don't the temp goes over 90 degrees.

What about something like this Texas Greenhouse Company, Inc.: Fog Systems I've used their fog systems to raise humidity and cool things down when I had a greenhouse out west. Natural humidity would commonly go below 4% outside and temps over 100 degrees F. With the foggers running (hooked to a temperature controller similar to a thermostat) I could lower temps by more than 20 degrees and raise humidity at same time. Just a thought.

I have 1/2" poly tubing connected to my gh water supply with a filter and 25lb pressure reducer, and have a line running down both sides of the gh near the ceiling. I just got through trying a 1/2gph fogger nozzle on each line, but it still gets the plants too wet. I've thought of trying a 10 micron fogger nozzle, but I haven't found a company which says 'here it is, this is what it costs'. I think I could hook up a regular water timer to cut on and off at certain times, but it would be much bettr to have a humistat so it could be controlled automatically. Two places I checked want over $1,000 for an automated system. I'll hang the orchids under the big oak tree and spray 'em with the garden hose before I spend that kind of money!

Really! Try MistKing This is Marty's company (He hosts this board) I have one of his setups and it's great. Not expensive either. Texas Greenhouses's was much less than 1000 too.

Thanks Ross. I've jotted down their phone number and will call them Monday.