I can only speak to cooling as I have no artificial heat in mine, I figure it's only needed maybe 3-4 nights a year and then I just drag a space heater in there and run it for about 10 minutes to get it warm. I also keep a good ammount of thermal mass in my GH. Winter is the perfect time for a GH down here, even at the coldest the GH stays fairly warm. As to coolling, the easiest way that I can figure would be a fan and a mister. I have neither right now and I am on the verge of losing everything in there everyday. I come home from work around 3:30 and immediately get the mister in there and open the door and I am able to bring the temps down to the 80's from 110-120. So I would guess a swamp cooler would work...but I plan on just getting a fan with a timer and a mister on a timer...(someday). Otherwise I think I will have to empty the GH, as it's really doing the plants more harm than good right now. I'm not sure if that helps...but those are my thoughts.

Thx everyone for the advice. Because I'm also fighting the dreaded scale on some of my house plants (2 years!) and absolutely nothing has eradicated it I finally went for the big guns and used Bayer advanced tree and shrub on everything. That was Sunday. So far so good. BTW my pest control guy who comes out to spray for roaches said that he HAS seen them come out of the soil and that they can live without a head for several days. Arghhh!!!

are you organic? If not, I have friends who dose their plants with Beyer's systemic, which lasts months. If you are, you could spray the plants with alcohol before you bring them in. Don't let it get on the dirt. Or you can use a insecticidal soap or something.

plants can only leave hawaii w/ agricultural stamps from an approved company that has passed inspections. if they are able to ship off the islands they should have stamps, unless they have such poor quality plants they fail inspections. if you are in CA or FL forget about landing in a plane & carrying on a plant w/soil/bark, seed, cutting, fruit, food...! CA has the MOST strict rules about what comes in & out of that state, FL has the second most strict. if you try to carry on one of the above mention products and they catch you on the CA or FL end it's a federal offense i believe. i'm guessing most other states, especially those who don't have much agriculture, are much less strict. one med-fly brought thru customs illegally on any of the above mentioned products can produce thousands of offspring, potentially ruining crops for yrs and yrs, & costing billions of $$ in losses. i am in charge of shipping landscape plant materials via semi from NC to TX for the company i work for, we take sending our plants to other states very seriously. it only takes 1 shipment of 1 tiny virus, bug, weed or microbe into a region where that pest has never existed to ruin all plants and agriculture for centuries. several yrs ago Monrovia plants in CA shipped a few azalea standards into FL that were carriers of Sudden Oak Death which had never previously been found in FL. we have different oaks in FL from CA and suddenly old live oaks were dying off in months, it took months of researching to figure out what had happened, thousands of oaks have died since then. monrovia is pretty much banned from shipping much out of CA into FL now. i would have them ship you plants back ~ liz Here is a link that might be useful: hawaii ag rules