Other end, with door.
(Havent figured out how to put multipul pics in a post yet.)

This is the stove temp with only a 29 degree rise.
There is about 500# of granite beside the stove to absorb some heat.

I'd be happy with a 30-degree boost. I only get 15 at most and that is with a much larger stove, but it's in an external building to the greenhouse, which is a 14x48 quonset with a double poly layer.

There is no good way to heat a poly structure, because the r-value stinks. The only thing you can do to conserve energy is to have an insulated blanket like a pool cover that you put on at dusk and take off at dawn. I have seen pictures of Chinese greenhouses built that way.

Hi Cole.
Do you remember where you saw the pictures?
I have been trying to come up with a way to
insulate over night that isnt too time consuming.
Thanks.
Jason

This is a pic of the same style. The end building houses a combustion furnace. I don't know what they burn, probably whatever they have. You can just barely see the insulated curtain - it's rolled up at the top. Every night they roll it down to conserve heat.

Here is a link that might be useful: {{gwi:312119}}

Thanks Cole!
Jason

Cole made the same suggestion I came to say. I have a 10x12 hoop house with 6mil poly. Adding heat hasnt been the issue its loosing the heat that it keeps the heater running. Whatever you can do to minimize heat loss is the key. I have had some luck with just throwing a simple blue tarp over it at night.

Mike

I just finished my double layer/inflated hoophouse with a wood stove for heat. I too would kill for a 30 degree heat gain. I get between 10 and 15. My stove is large and has an aggressive blower that really pumps out the air. I also use two fans to move air around. I direct the fans at an angle towards the ceiling to push the warm air back down the far wall. I also have my stove inside and use the single wall chimney pipe which climbs up to the ridge and travels all the way across the building so that my fan action helps capture any heat coming off the chimney pipe.

Right now I am burning up an old pile of fire wood - its not the best and I have to manage my fire a lot. If I can master this system I will buy better hardwood and not have to baby things so much. If I can't keep it really warm I will trim the truly tropicals from my plant collection and just grow what I can with minimal heat. Luckily I live in mild zone7b and only have to deal with a week or so of below 25 temps and most of my plants can take it down to 28.

In my hubby's construction biz, if they put in a radiant heat floor (heated water running thru pex tubing in concrete floor), they always put foil faced insulation on the ground before pouring the concrete, foil facing up. This kept the heat from radiating into the ground and pushed it up into the room. I would think the same principle would apply to your rock floor. If it were possible to put some foil face insulation under your layer of rock, you might find it helpful.