Another Heating Question

Hey All,

This is my first winter with my greenhouse (its 14 x 25 Quonset). I'm in zone 6a and feel I will need some type of heating. I'm thinking as long as I can keep it at a minimum of 40 degrees my plants should be fine. I have perennials, shrubs & some trees inside. What are your thoughts on the vent free propane heaters? I have double poly with bubble wrap and I'm also considering a solar pool cover for the outside. Temperature here in the winter can get to 0 degrees.

Thanks all for your advice.

Denise

Denise I bought a blue flame vent free heater and I was real sorry. Not about the blue flame part but rather about the vent free part. The heater will use up all available oxygen in the GH faster than you think and once that happens the heater will shut off. This usually happens at the worst time (like nights or during storms).
My advice would be get a vented heater. Blue flames are nice but I can not recommend a vent free one.

MollyD

"Vent free" doesn't really mean vent free. As Molly said, every such heater requires a source of fresh air and oxygen. Some greenhouses have enough air infiltration so that you don't have to worry about it. But if the GH is at all tight (and Molly's is apparently very tight), then you will have to leave an opening for the air. There are guidelines or formulas for the size of the opening.

Many university extension service websites, GH manufacturers, and other sources will recommend against unvented heaters because of the potential buildup of toxic gases which can damage plants.

There are GH owners who use these and have done so for years without incident. Molly and I will not be among them.