Average cost to upgrade a 60x12 Greenhouse to Controlled w/HVAC?

Hello rollitup community. This winter my grow buddies and I had a our winter crop torn apart by the frost in our 80x12 greenhouse. We live in Southern California, but the winter was cold and wet with many a december/january night in the 30s. Some of our other greenhouses were flipped on Halloween, so once the frost hit, they were around week 5-6, whereas this greenhouse was on week 2. The buds ended up stretching and they will not be salvaged for much as we now have to make concentrates with it. I wanted to do some research on what I need to completely seal this off. We have a greenhouse tarp that is transparent, but it has holes, so that wouldnt do as a good exterior panel. What will we need to enclose an open greenhouse? What machines do I need to buy? Cost? What am I forgetting? Anything that a fellow like me who is ignorant on a controlled greenhouse would need to know. I'll show some pics of the setup if I can upload them. It also has 10 1000w gavitas using a vegan no-till system (I recommend notill to all the soil growers )

to do it right you need double wall....

2 layers of film and put a blower in middle to create a barrier. I have had it down to 17 degrees several nights in a row and no problems in my greenhouse. I only have 1 layer of film but its sealed right all the way to the ground. The heat that is built during the day heats the ground and everything in it and it will hold some heat. Ive had it so cold that their was ice crystals all over the plants but nothing wrong with them the next day. I've had plants outside in the woods down to 20 degrees but had overhanging trees covering the plant from frost and they did fine. I've had plants where half the plant was burnt off from frost and other half just fine because of over hanging branches. Some plants withstand cold better as well.
You can put one of those rocket stoves in it

Greenthumbskunk said:

2 layers of film and put a blower in middle to create a barrier. I have had it down to 17 degrees several nights in a row and no problems in my greenhouse. I only have 1 layer of film but its sealed right all the way to the ground. The heat that is built during the day heats the ground and everything in it and it will hold some heat. Ive had it so cold that their was ice crystals all over the plants but nothing wrong with them the next day. I've had plants outside in the woods down to 20 degrees but had overhanging trees covering the plant from frost and they did fine. I've had plants where half the plant was burnt off from frost and other half just fine because of over hanging branches. Some plants withstand cold better as well.
You can put one of those rocket stoves in it

Click to expand...

Wow. Thank you. That was some amazing info. I like the double layer idea. How well will it work in the summer time to keep the Temps down? We are running gavitas so it may get really hot at night in veg

harveylitup said:

Wow. Thank you. That was some amazing info. I like the double layer idea. How well will it work in the summer time to keep the Temps down? We are running gavitas so it may get really hot at night in veg

Click to expand...

Have an extraction fan/s hooked up to a thermometer. Set and forget.

harveylitup said:

Wow. Thank you. That was some amazing info. I like the double layer idea. How well will it work in the summer time to keep the Temps down? We are running gavitas so it may get really hot at night in veg

Click to expand...

Need enough fans to move air through the tunnel. I personally made roll up sides on mine with pvc pipe. Got wiggle wire that makes it so easy to take the plastic on and off the bottom to seal it. Shade cloth also cuts down on the temps a great deal.
I have had plants in mine for over a month now. Have had many nights below freezing.

I have some inside under a few 600 watt lamps all in get planted same time as the ones in the greenhouse. Both are pretty much the same size and the inside ones are under light 24/0. I have lights that kick on for a couple min in the greenhouse to "wet the leaves" with light to keep em in veg. All those lights are are just simple 11 watt led light bulbs. Gonna turn them off here soon to start flowering. Going to fill the house up with the other clones I have before turn the night light off.