Turn the fans in or out?

I know i've brought up this subject before, humor me, cause i'm bringin it up again LOL


I have a l6 x 30 greenhouse with 3 huge windows on each side and front and back door which all stay open during the summer, I have 2 layers of plastic with 4 inches of space between the layers of plastic.

A highpowered fan at the front door facing in, and a small house fan at the back door facing in. Yes Iknow, most say not to do this,

I find that themore air that blows inthe greenhouse the faster the plants dry out, which is helping . The humidity is so high that if there isn't enough wind flowing through that the plants don't do well, and I have now a few geraniums with mold spores in the dirt and the leaves are curling up and the plants are going to die, no matter if I transplant or not their on their way out, cause i've tried changing out the dirt and nothing is helping them, The dirt I wash off the plants is loaded with little white dust , (spores). Getting off the subject I know, but ,

Seems the plants at one end, the end with the high powered fan facing end, are doing so much better thanthe ones at the other end. The ones that have gotten the mold in the dirt are at the other end. They don't dry out as fast as the ones on the end with the high powered fan, I want to get another high powered fan at the other end. Their like 40.00 at walmart. husband says I do't need it, that it would be too much wind going through the greenhouse. WEll, I haven't told him what's going on with some of the plants at that end. He might change his mind if he knew.

Question is, would it work best to point both high powere dfans towards the inside o f thegreenhouse, there's plenty of window for the excess wind to blow out, I need it to dry out in there, I need the plants to dry out, I am going to stop watering daily and water the geraniums every other day now, to see if that will help.

I keep the geraniums inside the greenhouse because there's over l00 of them and I have no place to hang them outside. So the greenhouse pretty much stays full year round, and crammed to the point that I have no room to walk in the winter time. I've got to bring the temps down in the middle of the day,

it got up to l07 today in there, but right outside the GH it was l05, it's not that hot here, only 98 but hotter outside the greenhouse it seems, cause it's in direct sun.

No shade cloth, but the inside plastic is white, not clear and it offers quite a bit of shade to the plants. Sorry for rambling.

kathy_ann

My fan blow out, and my humidity in the greenhouse (and outside) is normally high despite a drought. Hey! The humidity outside is normally high, despite a drought.

It's a small greenhouse, so I only have one window fan. The theory of having the air blow out is that it is removing the hotter air which is being replaced by 'cooler' outside air. Air movement is key whichever way that you choose.

I mist and water plants selectively almost every day lately because I have seedlings growing and a large coleus that lets me know when it is getting too dry.

I also keep the front door of the greenhouse open. That's for the incoming 'cooler' air.

Ann B.

You mean the air outside is cooler? my theremometer reads that it's hotter outside than in the greenhouse and it's still like l04 in the greenhouse, though it's not usually l07 here in Arkansas, but outside the greenhouse in full sun it's that hot LOL

I now have 4 fans in the greenhouse two on one end blowing in and the other ones at the other end blowing out. seems to be drying it out in there, or so it seems anyways, I did cut down the watering too.

kathy

You need both. You need a fan at one end, blowing in, bringing in fresh air. You need a fan at the other end, blowing out, to remove the hot, moist air. Ideally, both the intake and exhaust fans will move the same amount of air (cubic feet per minute). There's actually a formula for figuring out just what size fans you need, depending on several factors (average temp in your region, your target temp, greenhouse materials, etc.). Smaller fans, located throughout the greenhouse, to keep the air circulated are a must-have, too.

Thanks for thehelp