Not knowing the set-up it's hard to say. Perhaps you need a taller stack? A better draft will take out more of the smoke. Another thought: If the stove could be put in a place near but outside of the growing room (a shed?), the stovepipe could be routed thru the grow space, leaving some of it's heat behind.

I've been watching your post since you put it up thinking someone would have a marvelous answer because I want to do the same thing. The only thing I can tell you is vent the stovepipe out a window and up. Make sure you have a good damper. I'd like to see a picture of your setup. do you think you could post one?

river22, I will try to send you some pictures of our set-up ( real busy right now w/ seeding). I don't know how big your gh is, but we also picked up at our local home improvement store a kit that you can use to turn a steel drum into a wood burning stove that we plan to use for our bigger ones next fall/winter. we got them for $25.00 on clearance.

Right now I don't have a greenhouse but hope to build one in the future. I like to get ideas.