Greenhouse Exhaust ideas and questions

[Cesaro]

I need some help with venting my greenhouse better. It's a Post and Rafter design, and measures 8x16x10.

Last year I just had two rinky dink window fans one pushing air in while the other pulled in air the side bottom vents were never opened and the door always stayed close. Needless to say I had some issues with the excessive heat. I was actually watering 10 gallon smarty pots multiple times a day and the plants seemed to love it.

I didn't yield what I thought I would, some of it was some god awful garbage strains, and the other I think was just how HOT it was in there. I had some bud rot in my big colas as well, but not as bad as it could have been.

So my question is, I have a couple can fans that each push a little more 800CFM. Would it be possible to hook both of those up at my roof vents to vent the room, while on the bottom have the side intakes pulling air in. Would this work? The air exchange is good, with both fans it would replace the air every minute. Then on the side vents, the air being sucked out should cause the vents from the bottom to pull air in.

Anyway, I'm struggling with how to tackle this issue so any input would be really appreciated. I could just buy a nuce greenhouse fan, but I'm kind of broke, and don't want to spend couple hundred bucks on a real greenhouse fan if I can use all the indoor equipment I got.

 

[SemperHighGuy]

Hi! New to the forum here. I have a greenhouse (two actually) of nearly the same dimensios of yours. My ceiling is 10' and the summers get warm here but not so bad this year. I'm using a solar attic fan from Home Depot. Works great but getting the optimal performance I had to figure the hottest time of day and point the solar panel in that direction.
I have 3 monstrous sized plants from some bag seeds. So far each plant is about 8' tall and at least 4' wide.
Venting is a problem for me because it seems the air heats us as fast as the fan can move it. So I cut slits in the plastic and the greenhouse has only gotten to 101 on two occasions. But I have a plan!

On the rafters I am going to make a frame and put a hinge on it. It'll be covered in plastic like the rest of the structure. It'll be hinged at the low point of the slope. When it gets hot during the day I'll open the roof and the door to the greenhouse and let it cool off. I am going to install a mist system too to keep things cool and wet on a schedule.

On a side note...I'm tossing around a few ideas to shade the greenhouse using ground cloth. I'm still working on the particulars. Probably PVC pipe and paracord like a rollup blind.

I want to get two harvests a year out of them.

I have extensive experience with alarms, home theater, automation and networking. I am designing a watering and nutrient system. I'm growing in soil. The hydro system I had was just too high maintenance. So on paper I have everything worked out including CO2. I'll be posting a journal next year on the upgrades and the grow.

 

[Cesaro]

Hey man, I actually installed a swamp cooler. I suggest you do the same if you can(dry climate). It is keeping my greenhouse under 95, it's exhausting a shit load of air, as well as pushing in a lot of fresh air.

I'll update my grow journal here with more recent pics. Check it out.

 

[SemperHighGuy]

I'm trying to use as little electricity as possible. What are the specs on the swamp cooler? The humidity here is about 20 percent if that.

 

[Cesaro]

It's 1/2 hp which is a lot for a swamp cooler fan motor. I think that's around 500-600 watts. PRice isn't bad maybe 40 bucks a month?

I'm sure you could get an even smaller cooler, the one I'm using is for a house, so it's overkill most likely.

 

[SemperHighGuy]

I'm looking at trying an experiment with the second greenhouse too. Using colored gels. The kind they use for studio lights. I want to see if I filter light...sunlight through a gel screen of orange of even perhaps another color what effect it would have on flowering on individual plants.
Although my plants are gargantuan I don't think they will finish flowering until late October. The whole greenhouse project for both was less than $1000 in materials.
The watering regimen is going to be fun to design. What I am thinking of is a gravity feed with a garden timer for nutrients.
The CO2 system is pretty much designed...I have to build a prototype.