Second layer of plastic and frost cover?

FourOaks · February 7, 2018

Alrighty, I have a question for you fellow High Tunnel/Greenhouse growers.

Before I ask my question, let me explain what I did last year, so you can get a better idea. Then, we will go from there.

Last year to keep my plants comfy cozy, I installed a small propane fired furnace in the end wall. It came out of a camper. I dont recall, but I want to say 18000 BTU? But im not 100% for sure on that. The furnace is controlled by a thermostat. I usually kept it at about 55 degrees. The lowest setting.

I ran 4 inch duct from it, up to the benches. I suspended a piece of plastic from the hoops, on the inside. I basically created a heated tunnel, within the High Tunnel.

This worked. I also installed a switchover valve so 2 tanks were attached, allowing me to never run out of propane. Im fairly pleased, but I feel like something better could be had.

Being that I am doing a lot more plants this year, I need to maximize what I have. My thoughts are to move the benches into the middle of the High Tunnel. I have enough bench space to cover a 4 foot by 24 foot area. Might have to make more.

Then, bend 10 foot PVC into an arch over the benches, do maybe 3 sections.

Previously covered with additional plastic. But now im wondering. Is there something better? Does anyone know the R value of Frost Cover, or Row Cover?

Maybe combine the 2? Drape light weight row cover over the plants in the evening then lower the additional plastic down? Or put row cover OVER TOP of the plastic layer to act like a blanket?

Any thoughts on this? In the end, im trying to keep my propane use in check, so I need to find some way to insulate the plants.

Right now, Im ok as all my seedlings are indoors under lights. But we all know how quickly you can run out of room.

This is the setup from last year. Not the prettiest, but it was spur of the moment, and it worked.

February 7, 2018	#1
FourOaks Tomatovillian™ Join Date: Mar 2016 Location: NC Posts: 511	Second layer of plastic and frost cover? Alrighty, I have a question for you fellow High Tunnel/Greenhouse growers. Before I ask my question, let me explain what I did last year, so you can get a better idea. Then, we will go from there. Last year to keep my plants comfy cozy, I installed a small propane fired furnace in the end wall. It came out of a camper. I dont recall, but I want to say 18000 BTU? But im not 100% for sure on that. The furnace is controlled by a thermostat. I usually kept it at about 55 degrees. The lowest setting. I ran 4 inch duct from it, up to the benches. I suspended a piece of plastic from the hoops, on the inside. I basically created a heated tunnel, within the High Tunnel. This worked. I also installed a switchover valve so 2 tanks were attached, allowing me to never run out of propane. Im fairly pleased, but I feel like something better could be had. Being that I am doing a lot more plants this year, I need to maximize what I have. My thoughts are to move the benches into the middle of the High Tunnel. I have enough bench space to cover a 4 foot by 24 foot area. Might have to make more. Then, bend 10 foot PVC into an arch over the benches, do maybe 3 sections. Previously covered with additional plastic. But now im wondering. Is there something better? Does anyone know the R value of Frost Cover, or Row Cover? Maybe combine the 2? Drape light weight row cover over the plants in the evening then lower the additional plastic down? Or put row cover OVER TOP of the plastic layer to act like a blanket? Any thoughts on this? In the end, im trying to keep my propane use in check, so I need to find some way to insulate the plants. Right now, Im ok as all my seedlings are indoors under lights. But we all know how quickly you can run out of room. This is the setup from last year. Not the prettiest, but it was spur of the moment, and it worked.