man, with our new dictator in office, using that much electricity could cause you to be thrown in jail ;)

The poster above is correct. As it is, the (fake) global warming thing that just passed is going to cause the average houshold more than an extra $100 a month in electricity and natural gas combined. (and that is conservative estimate) I'd give that some serious thought... If you have the extra money to burn, that's great though! Another thing to consider, you might have DEA agents out asking questions, wanting to see what is in the greenhouse... They monitor exectric bills already! Cap-and-trade us into 50% unemployment, and back to the stone age.

wxman -- Ironic, isn't it, that we JUST really started to have summer, and now we're all thinking about what to do for the upcoming winter. Living in the north really does stink in some ways, but they again, we're not sweltering all of the time. I've turned my air conditioning on for a grand total of about 36 hours this year, the week before last when it hit 91 one day and 93 the next, then the cold front came through and we spent five days this past week with highs in the mid-60's (some "record low highs" were recorded in parts of S. Michigan last week).

I think you'd find that the cost of what you're proposing will be all out of proportion to the benefits, unless you're uberwealthy -- It's going to cost you probably $150 to $200 a month to run a spaceheater all of the time to do as you suggest. I used to do this, having a small greenhouse and no natural gas service in my area, but it cost more to overwinter the plants than it would have to buy them all new the next year.

The good news, I believe, is that you really don't have to keep them as warm as 70 degrees to keep some growth going, even if you could keep an average temp of probably 45 to 50 they would grow a bit during the winter, although probably not nearly as much as a Trachy would.

I think it's more important to keep the SOIL warm than the air, so you might want to consider a soil heating cable of some type around or through the rootball, if possible, even if it's just draped over the top of the ground and the mulched heavily.

Another thing to consider -- you may want to do as they do in Iceland and Norway, where they've found that, since HEAT is far more expensive to add to an enclosed space than LIGHT, use an opaque, insulating material like foamboard for your structure (like artictropical does in Utah), and then use a cheap and energy efficient CFC bulb to provide artificial light in the enclosure.

Great post's you guys! I agree."They"are raising our electricity 20% here because of the flooding and the ice storm we had.I was going to tell you that bit about the soil also,in my experience when the soil temp drops below the low 50s and certainly below 50F you will propably not see much/if any growth but if you have a good distance from your palms(outside soil temps)you may be able to keep the groud warmer.My soil temps ran 40-48F(lowest air temp 12F-14F)I think you did great to get your stuff through as well as you did and a lot of that had to do with the snow you had to insulate things.If you do want to build something cheap like I did,one thing I should say right off is that mine was protected quite a bit from the wind.I used cattle fencing 4'x15' made into an arch it was(the arch) roughly 5' tall and 10' wide I cut the end bar off so I could push it into the ground,the cattle fencing is about $20ish a piece(I used 4 and created an area 5'h x 10'w x 18' long.I think for me it is to expensive to try and heat for growth during the winter but if you can do it,go for it!I am working on getting more growth during the growing season out of mine.I think for your washys using black mulch/rock during or leaving partial covers on them to lift the temps around them(not necessary on Trachys)would get the job done better than trying to get growth during the winter,esp in these " low sun spot activity"? cooler summers and winters!
We may have had a record cool high temp too on the 4th,61F low and 66F high.Back to mid 80s now.Good luck!
The total cost was probably about $100 I spent $23ish on the4 cattle fence pieces and about $20 a 20'x20' piece of plastic tarp.Heres a pic hopefully,I have not been able to get pics to post directly from from photobucket

Here is a link that might be useful: