If I use a swamp cooler to cool, will this produce to much moisture for cacti etc. Here in NM it works really well I'm not sure extraction fans alone will do it.

I assume you mean in summer?

I guess I wouldn't put my plants right near the outflow of the cooler, but other than that as long as there is good airflow I sort of doubt that it is going to be humid enough to really be a problem, but maybe it gets warm enough in summer to have your plants outside?

It doesn't sound like a good idea. I would think you would end up with a very wet greenhouse. I wanted to put a swamp cooler in my greenhouse because I have mostly orchids but I suspected the catcus wouldn't appreciate it as much. Instead, I put in misters on the orchid end that run for 2 minutes every hour.

In New Mexico, you will have to run fans and have vents or you will bake your cactus. But with a swamp cooler, you would boil your cactus. My greenhouse is small, only 23 x 6 ft. I have 6 automatic vents, run 6 or 7 small clip fans constantly AND open at least one door in summer. It still reaches 110 degrees at times. Without all the fans and open door, I suspect it could reach 130. I suspect if it were more humid along with the enclosed heat, I would have mush for cactus.

I have an extraction fan up high and two inlet louvers down low I will be getting circulation fans. My GH is facing due south, with out side temps in the high 90s its going to get brutal in side. We use swamp coolers for the house which drops the out side temp by nearly 20deg but I've never checked humidity. Maybe I'm thinking of me not the plants? I intend to spend a lot of time in there summer & winter I hope. What is the ideal humidity for cacti?

I will put plants out side in summer if I can but we get strong winds 30 mile per hour gusts to 50, kills my garden plants beats them to death literally.

wiltshire said:What is the ideal humidity for cacti?

I don't know. But if you use a swamp cooler AND open the doors and windows, you may be the cause of more than the usual number of thunderstorms this summer.

And ice storms in Texas

I wouldnt. There is ambient humidity in my apartment anyway, and the touchy feely gentle cacti dont like a mix of cold and humid- stuff like parodia, eriosyce, echinopsis section lobivia, and some mammillaria species could die from the mix. Winter is usually for dry time.

Our average humidity is about 70-80% and our nighttime humidity is regularly in the 90s. Admittedly the temperature is uniformly mild (and cool air holds less actual water than warm air would) but these humidity levels do not present any particular difficulty for my plants, given lots of light and good air flow. I guess you have to weigh the potential risks of high temperature against the potential risks of high humidity.

Thank you all ,there seems to be many differing opinions I am surprised. Many people out here in the south west use swamp coolers I would have thought more of them would use them in there GH and sun rooms. I might just try it I can always shut it off before to much damage.

We lived for a long time in the Phoenix, AZ area. Most of the greenhouses there have swamp coolers. Most are commercial models, but a few people make their own. I've never noticed any problems with the ones I've visited. Greenhouses just don't work during the Phoenix summers unless they are cooled. I'd think your area would be fairly similar, Bob.

Karen, were they greenhouses full of cactus?

They were about half and half. Have had tropicals and others were only cacti and succulents. You should give it a try. Like you said, you could discontinue use if you found it to be a problem. I sent you a treemail, Bob. Click on the small envelope Icon at the top right of your page.