Winter Storage

[cairnview]

I am going to store my mixture of outdoor trees in my glass greenhouse which is not heated during the winter months on the center bench. I live in southwest michigan. The problem I believe is during the winter somtimes their is sun light which could
in crease the temperature above the freezing point. Could this alter the dorment period?
Thanks

[jpaulhamus]

Greenhouses can really warm up in the sun during the winter months which can cause problems with winter dormancy. I've been told that once temps start getting above 40 degrees for an extended period of time that this will bring some trees out of their dormancy. So you want to try to keep them below that temperature. They don't have to be kept at or below freezing all the time but the closer to it the better. Mid 30's is good in my opinion, it's cold but not too cold. I'm not sure how much a glass greenhouse would vary compared to a plastic one. I would think keeping a door or window open would help keep the temp down some, it's going to warm up in there faster if it's all sealed up with the sun beating on it. I'm not sure if putting a covering (something not clear) over the greenhouse would help or not, so the heat and light is reflected away some. I winter my trees over in my unheated garage, which stays in the low to mid 30's most of the time in the dead of winter. It only drops below freezing if it's really cold out(single digits or below). Last year when it was so mild here, lots of days in the 50's but cold at night, I had to keep the windows in the garage open to try to keep the temps down. Hope that helps.

[centaura]

Keep track of the temperatures and make sure that they stay below 35/40 degrees F. If it does start to warm up, are there windows or doors that you're able to open to bring in outside air? Also, you can cover a greenhouse with white plastic, which can help keep temperatures down.

Each tree species has a dormancy range, a period of time during which it needs to stay dormant. Once it's dormancy requirements have been met, the tree will react to temperatures that are above 50F. Going into the fall with the shorter days and cold months, you shouldn't see any issues with the trees breaking dormancy, since they have just started their winter slumbers. Starting in Jan. / Feb. is when you need to make sure that the temps in the greenhouse stay below 40F since that is when certain species will have completed their necessary dormant period and will just be sitting and waiting for temperatures to raise to being growing.

-Cat