It appears to me that the problem is too much light and heat in the greenhouse. Unless you water like crazy, the plants will dessicate. 4000 foot candles of light is plenty of light, and it's way too much for some plants. You need shade, air and more water.

I live in Florida as well and for me, low humidity has never been a problem, ever. Its a sauna 9-10 months out of the year. I live inland, no ocean breezes, the heat and mugginess settles in and never seems to leave. My greenhouse is 36 x 48 and the entire back wall (36 ft) is a big swamp cooler...cellulose pads with water pumped over them by a pump. I have two 36" exhaust fans that pull air through the wet pads in summer, and 8 attic fans to circulate air. I water daily, by hand (unless we are going out of town, then I have an overhead sprinkler system I can turn on). You can do the same thing by using wet towels, wet sheets and a fan like someone suggested earlier. It really helps to cool things off.

To make certain I have enough humidity in winter, I also have 3 water features in the greenhouse: a 50 gallon inground pond, a 20 foot stream with a small gurgling waterfall, that ends in a 2nd 40-50 gal pond. You might consider installing a water feature. They really add to the atmosphere and don't take up all that much space.

With the swamp cooler, I can keep the temperature between 80-90F even on the hottest days, which my plants seem to love. I don't utilize any form of shade cloth, spray on white out or anything else. I do have some lianas that form an attic canopy (Jade Vines, Thunbergias, Solandras, Rangoon Creeper) and they do provide some shade but its basically a full sun house.

Are you certain that your humidity meter is not in error? If your numbers are correct, you need to take measures to cool the greenhouse down.

I do have a few resident frogs, now that you mention it! They are freeloaders who came in from outdoors. Also have a few snakes. Everyone gets along though! I will try to take a new set of photos and start a gallery.

Hi Faerygirl...where are you in Florida? I'm in SPring Hill, on the west coast about 40 miles or so north of Tampa.
We have LOTS of Floridians here on OB :clap: but those darn Californians (tman, for example) are gaining on us! :shock:

Hi Susanne,
I am in North Central, Gator country to be exact. We get down to Marie Selby, Tropiflora and Fairchild pretty regularly, and have access up here to some nice orchids from a few local growers. But I confess I get most of mine from So FL. We are inland here in big G 45 minutes from the Gulf and 55 min from the Ocean, and being landlocked, we get a lot more actual intense heat in summer than, say, Palm Beach or Miami because of our lack of seabreeze. The humidity here is a killer. I guess that's why I can't imagine anyone in FL saying they lack humidity!

Our club is planning a day-trip to either the Tampa area growers or down a little further to the Sarasota area, sometime in May :cheer:

Have you gone to Redlands? ...and will you be going to the WOC next January? :banana: A number of folks from OB are planning on attending, and they're not all the Floridians! :clap:

I really thank everyone who responded to my greenhouse humidity problem. This has been an active and interesting thread, and there have been some ingenious ideas. I think this is what I'm going to do. I've had this greenhouse since May of last year, so this is my first Florida winter with it. Yesterday, the outside relative humidity was 13% and a dew point of around 19%. I could only keep the greenhouse temp down in the full FL sun by raising one side and/or opening the door; this of course shot my humidity you know where. I do have a fountain in there and have also been using a 4 gal house humidifier, but with the house open and fans running I cannot compete trying to raise 13% relative humidity. So, for right now I'm going to bring the temp down by blocking more of the sunlight (which will also help the light situation) and just do the best I can with the humidity. At night with an internal temp between 55-65 they get about 9-10 hours of perfect humidity due to condensation.
Summer and the rainy season are not too far away so I'm going to put this problem off until next dry season. But let's keep the thread going; it's prompted a lot of response.

Well you know what is gonna happen when monsoon season hits for sure, you aren't going to HAVE a problem! I can't wait for summer, I love the intense heat and tolerate the humidity (last summer I trained for a marathon in the heat, all summer long, then ended up having to bag it over an Achilles tendon injury). Its less than a month away! Keep the faith!