Light requirements for evergreens...

abqjoe

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I read that once temps are consistently below 40F that there are no light requirements for evergreens and that they can be stored in the dark. Is this correct?
 

aml1014

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I would day it depends on species somewhat. Both you itoigawa and pondy won't go fully dormant until maybe January where as your JBP will be dormant very shortly. Those super cold hardy trees really need some REAL cold to go to sleep, even more so then we're able to offer them here, just watch your juniper this winter, it'll change a bit.

Aaron
 

Dav4

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Below freezing. ...
My thoughts as well. Hardy evergreens, and particularly conifers, still photosynthesize a bit during the dormant season if the temps are in the 30's ...so they really aren't completely dormant. I kept conifers in an unheated MA garage successfully for a decade, but they didn't go there in until temps outside were consistently falling into the lower 20's every night, and I would let them freeze solid for 3 months every winter. As soon as temps started moderating and the soil and mulch started to thaw, they'd get moved outside. If I were trying to maintain the temp of an enclosure for my trees, I'd shoot for upper 20's to low 30's...frozen trees don't need regular watering and they don't break dormancy during periodic warm spells.
 

miker

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I have speculated about and seen spruce seedlings or small trees buried in snow for months in the Rockies for example. These clearly do fine without light for extended periods as long as below freezing.

I successfully wintered a spruce in the refrigerator last winter. Kept it in for about 3 months and set it in sun once every 2-3 weeks and it came out of dormancy and did fine earlier this year.
 

Paradox

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I've been at this for only 5 years but so far....

I've kept conifers in an unheated, dimly lit during the day garage, where temps ranged from 30 to 50 all winter (I know that high temp is too high).

Last year I kept confers in a cold frame that was completely dark unless I opened it and temps stayed between 30 an 40 all winter. The cold frame worked so well that it has been expanded to 2x it's original size and I will put as many of my pines and junipers that I can fit in there.

The first 2 to 3 years, I put trees away a bit too early. Last year, I had them out until we had temps predicted to go below 25 or so then I brought them in.

My trees are all still outside right now (except trops of course) and looks like they will stay there for now. We will see what the weather says for next week.

I have not lost a pine or juniper overwintered in either my garage or coldframe.

Ive left a mugo, a scots pine and San jose juniper out all winter and all lived. I would not recommend it though.
I left procumbens juniper out the same year and they all died.
 

Leo in N E Illinois

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I too have stored evergreens in dark below 40 F for several decades. No problem. If tree going in is healthy, lack of light is minor issue. But it MUST stay below 40 F.

True many evergreens photosynthesize at slow rate right down to the freeze or slush point of their sap. this can even be a little below 32 F. But rate is so low that for most in good health darkness is not an issue.
 
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