Oh the (no) Humidity!
 

Greetings:
We have been enjoying what is colloquially called 'juneuary' in Western Oregon. Until yesterday that is. I moved the 'chins into their new summer home yesterday afternoon.

Today I woke to find the overnight low had gone down to 48F. Yikes. I didn't have a thermometer in the (toy) Greenhouse yet. Everything looked fine.

GH is on the West side of the house and I knew from observation it wouldn't get any Sun until after 1PM. I moved their plant light into the GH and it is set to come on at sunrise.

First question: is it worth it to just leave the lights on their usually sunrise/sunset cycle or have them go off at 1:00 and come back on at ... ??? More observation. Looks like shade from a nearby building limits actual sun to around two hours from 1:00. Leaving the lights on for now.

Now for the real issue. In the living room the humidity stayed around 50%. I thought it would bee much lower and it would be once the A/C started being used. I was shocked to see it plummet right down to 25% as the temp went north of 80F in the Greenhouse.

I brought a plastic storage tub and filled it and that did nothing. Finally I dumped out some of the water on the ground and that got it into the 38% range.

More plants would probably help but for now its just the seven or eight. Is there something automatic and not too expensive that I can do to get the humidity back into the 50's? Actually I had ben hoping for much higher.

Advice on this and also how to fill up a (small) greenhouse in not too long of a time gratefully appreciated.

Unless you have particularly sensitive orchids, fluctuating humidity isn't going to be that big of a deal to most plants. 25% RH during the hottest part of the day isn't that bad (sure, it could be higher) and the RH will rise as the evening and overnight temp drops. If you have extreme enough day/night temps and a high daytime RH, you could end up with 100%RH overnight which encourages disease, unless you're going to vent the excess humidity manually when needed.

If you do want to raise the humidity in a small portable greenhouse, a regular home humidifier with a built-in humidistat may be enough if the greenhouse is well sealed. I've seen people mention a storage tote filled with water + a pond fogger and the benefit is the tote has a much larger reservoir capacity than a home humidifier but you'd have to add a humidistat to the setup yourself or come up with another way to keep the humidity from getting too high.

My humidity only occasionally gets UP to 25%. Bifoliate Cattleya don't seem to mind to much...

Thanks! This is exactly the kind of reality check I needed. I love this Community. Had never heard of a 'pond fogger'. Hmmm. 68F and 55%RH at 10:20PM. Tomorrow is another day ...

When I lived in UK - long time ago - I had several small, temp greenhouses at one point until I got my glasshouse built. To increase humidity I had an old towel suspended from the top shelf and dangling down into a bucket of water to increase the area for evaporation. The greenhouse with the towel was on average 15-20% higher RH. The towel did get manky pretty quickly :D