Keep them outdoors. They need the cold.

If they will be in pots until spring, plan for temporary protection on coldest days/nights.
A plant in a pot is considered to be one or two zones more tender than if in the ground.

I am a little north of you in the philly area. Last winter i had a 2 year old ebay tree outside.'Sister ghost' I received in the fall. It came bare root. I stuck the little gal in a big 35 gallon pot that was 1/2 full of potting mix from a previous planting. This was just until I found a suitable pot for the tree.
To make a long story short--- The tree stayed in that pot all winter.I did emergency winterizing at one point by dumping mulched leaves over the whole tree.It was covered in leaves and snow most of the winter. The tree survived. Of course I don't recommend this procedure, but rather shows the resilience of trees.

This year however,my small trees will be coming inside to my unheated basement for the worst of the winter.
If I where you I would keep the trees close.When the weather gets rough...bring them in. You want to monitor temperature while they are inside. We don't want to trick them to come out of dormancy early by being to warm. Also monitor water. There will be no snow melt to provide water to the roots inside. Of course we don't want to over water and rot the roots.The trees don't need much water in dormancy but they do need water.
Anyway thats my plan--- in for the worst of the winter and back out for the thaw. I'll let you know how they make out. Good luck!!

Sister ghost inside

Thanks for the suggestions!
Qwade, did you mean a 3.5 gallon pot? I can't even imagine how big a 35 gallon pot is but I surely don't have anything near that big, and the pic you posted doesn't show a huge pot so I am assuming that's just a typo. Btw, I LOVE that tree. Never heard of 'sister ghost', will have to add that beauty to my list.

So I guess then my plan when my little trees come, will be to plant them in whatever biggest pots I have (3gallon, maybe 5), in Al's gritty mix (or could I use the 5-1-1? I already have a batch of that mixed up but would have to go out and buy the granite for the gritty mix), then bury the pots halfway under the soil next to my house. If we have a 'regular' Maryland winter, I will just keep them there but if we have something crazycold like last year, I will bring them into the darkest corner of the sunroom (my sunroom is on the southeast side of the house anyway and not super sunny). Give them just enough water so they aren't really dry.

Does that sound about right? Please feel free to correct any specifics. Thanks!

No misprint! I had a 35 gallon pot from a pine Tree (P. Parviflora) that i had planted. Yes it i a huge pot. I think that is what saved the plant.I was not planning on planting it in there. I was busy that day and it was just a convenient pot with soil already in there. Like i said not a recommended way to over winter.
For pots in the ground I have used a pot in pot system. You bury an empty pot in the ground and stick your planted pot inside of the buried pot. Makes it very convenient,
As far as soil the 5-1-1 or gritty mix are both excellent.I have a hard time finding pine bark fines so I usually use my modified gritty mix. This usually consists of course perlite, granite,turface type clay product,and a regular peat based potting mix. I mix in equal parts or whatever I have on hand.Drains well. I don't get that concerned with soil mixes. I just make sure I water efficiently and that the soil drains well. I usually have to repot every year-- 2 at the most so the soil gets renewed. You can get bark fines in the Baltimore area? I travel down the 95 corridor sometimes.

Everyone is foreseeing another brutal winter so maybe it will just be a normal one. You never know what mother nature will do.

I have kept my little trees inside my garage, which does not freeze but does get as low as 35 degrees when it is super cold outside. The trees have done fine in there. I plan on keeping my new "Jordan" inside the garage this winter. I feel like it is too small to leave outside all winter. I leave it outside as long as I can and put it outside in the spring as soon as the weather is getting nicer. If a cold spell comes, I just put it back in the garage for a night or two.

Linda

Wow Qwade that is ginormous! Thanks for the tidbit on the pot-in-pot method, that sounds super easy and I will def be using that one.

The info on pine bark fines:
-- The Mill of Bel Air 410-838-6111 (there are 6 locations in Maryland-- check the website for more, themillofbelair.com)
-- Hollins Organics in Baltimore 410-828-0210 (2 locations, hollinsorganic.com)

I posted about them both when I found them back in late spring and know that the Mill still has them but never went out to Hollins so you'd have to call. Interestingly, 2 associates at the Mill told me they didn't carry it and had never even heard of it but then I found it outside while walking around. The Mill calls it 'soil conditioner' but upon close inspection the only ingredient was 'partially composted pine bark fines'. So there you have it. Makes me wonder what other farm supply-type stores carry it unknowingly.

Tropic_lover, I've read about others moving their maples into their garages. I have room in there for mine and could certainly do that too but worried about lack of sunlight--- that's ok then I suppose? My sunroom gets almost as cold as the garage since it's actually not on the sunny side of the house so I figured some light would be the better of the two options. Correct me if I'm wrong though.

I'm going to get a thermometer for our sunroom this year. Can anyone tell me what would be considered 'too warm' for a maple to remain dormant inside?

p.s. something I forgot to mention that is of key importance to my post:
Last winter I lost my Mikawa Yatsubusa that was in a 5-gallon pot. I hadn't buried it so maybe that was why, but it had survived 2 other winters in an unburied pot (the first year in a 3-gallon and the second in the 5-) so I never thought to do anything differently. I bought it initially when I knew much less about maples than I do now (which still isn't a lot, admittedly) and chances are I did other things wrong, like maybe let it dry out or maybe watered it too much.... I really didn't pay attention to things like I do now. But anyway, it was a lovely little tree and saddened me greatly. So I'm maybe a little sensitive to the issue now and want to do everything I can to avoid that happening again...

I appreciate the input Ken but while your winters are surely much harder than mine, ours last year did indeed kill quite a few trees. Even established ones in the ground. And not just in my neighborhood- I am a hairstylist and have several clients who reported dead trees for the first time ever, all around Baltimore. Maybe it's not as much "how" cold it got here as it is that OUR trees weren't accustomed to it? I have no idea... but as I said in my latest follow-up, my little Mikawa Yatsubusa bit the dust too. Maybe it wouldn't have if I'd have had it planted in the ground as opposed to potted but I'm just not ready to put my trees in the ground yet-- I don't know exactly where I want each of them permanently so I want to be able to move them once I decide.

First bc I want to see how their fall colors compare to each other so that I can have a speckling of yellows and reds throughout. And second, to see how they mix in with whichever conifers I end up choosing. I don't relish the idea of digging up a bunch of trees that have already started sending roots out all over the place, in order to have them rearranged better. I definitely DO plan to plant them permanently at some point, within the first 2 years of their new lives here. But not yet.

I don't know if bringing the trees inside is the best way to kill them. I have found much quicker ways.

My reasons for JM's in pots are somewhat similar to Nikki's. However, my main reason is I just like to grow trees in pots. I am a bonsai enthusiasts, not an artist yet, but I have managed to keep some trees alive in small bonsai pots.
I have this niwaki / bonsai kind of theme in mind. Bigger trees in bigger pots.

Now i agree it would be a lot easier to grow that tree in the ground. I choose not too. I think the small trees are a lot safer inside.
We get a lot of freeze/thaw. This can saturate and rot your roots. Drain holes freeze in the bottom of the pot while the top melts. Hard to keep track of in the dead of winter.Ice damage was brutal this year in my area. Mostly on those long pine branches ( P Strobus) but I am sure the maples took a hit too.
So I'll take them in for the worst of the worst. Keep them cold indoors. They will sleep and probably not even know They are inside.

I guess this thread could have been in the container forum---also a good fit for the' tree in pot'( Bonsai) forum---or the tree forum--but it made a nice conversation here in the Maple forum. All great sources for this subject.

Nikki thanks for the pine bark fines info. I m taking the wife and her friends to DC Saturday so I will be passing your area. Will try to grab a bag or 2.

Im going to try and ditch the girls and go to the arboretum. I love that place.Lots of nice maples plus the dwarf conifers. The women have their own agenda--I took them their 1 to many times and they usually don't share my enthusiasm for the trees. lol

Also for the record---I must admit to not cleaning tools. I use pruning shears, scissors, etc. I do have a tool similar to a knob cutter not concave that works well. Concave cutters are nice and i will probably get one eventually.

oh
After rambling on about DC, Arboretums, My wife,Pine bark fines and other somewhat off topic subjects. I forgot to answer your question.

No sun needed for a deciduous tree in dormancy. No photosynthesis going on thus no light needed.

below 42 f is my go to number. my number. non scientific. check other sources. Don't trust everything I say as fact. lol

Ha no problem qwade and good luck with your endeavor. I've been trying to get to the arboretum all summer (after it was recommended so highly by folks here and I then checked out the website, yowsa!) and will now have to settle for fall; the little ones kept me too busy. I did recently get my mom to agree to come with me and we have a rough goal of next week or the following. Isn't it a shame that more of us aren't in coupledoms where BOTH partners share the obsession?? It works both ways though-- I suppose I could try harder to develop a taste for football, auto mechanics or America's Got Talent but if you try harder, it's not much of an obsession now is it... For today, I am grateful that hubbie does all the heavy digging and lifting when I ask him to. He does enjoy planting and nursing grass seed in our bare patches, so I think there might be some hope for him yet. Time will tell...

I giggled about "quicker ways" to kill these little maples. Picturing someone really attacking the poor things, furiously hacking at them or setting them on fire. I do see what Ken is saying as it seems that the colder-than-here pacific northwest is where so many of these mail order trees come from so I don't understand why we'd have problems here but your mention of the freeze/thaw seems a likely candidate. And we did have several days here last winter that were below 10degrees, I think a couple even below zero. Harford County is usually several degrees colder than Baltimore, sometimes as much as 10.

And I second the ice damage- perhaps that was a bigger culprit to the deaths of the trees I heard about. I didn't personally lose any other than my little maple but my HUGE pine tree (of some sort, I def do not know my evergreens yet) lost like 8 major limbs! It looks so sad now, big ol' holes.

Anyway, thanks for the info on the dormancy/no photosynthesis/no light needed. Boy does that seem obvious now. Think if I do need to move them, into the garage they will go. Then I won't have to worry about the sunroom getting to 42degrees (or whatever, hehe).

Here's a pic of one of our huge evergreens. I didn't take it for this post--already had it in my folder-- so you can't see the entire tree.. and it isn't the one with the holes anyway. But there it is nonetheless. Maybe someone here knows what it is?

I'm going to see now if you have any pics posted of your bonsai. That's much more than I can imagine taking on at this point in my life but I do always love to look at others'...

I grow ALL my JM's in containers and zone 7 is not an area I'd be overly concerned about leaving them outdoors in. Maples in containers are more vulnerable to winter cold but with regards mostly to the roots, not the top growth. Damage can start right around 25F so that's the number you should be concerned about.

That doesn't mean you need to take them indoors. In fact, any sort of heated structure at that time of years - in full winter dormancy - can be more harmful than cold. An unheated basement or garage may be all that is necessary and only for a short period of time while the weather is worse than normal. And there are other ways you can protect these container plants - heeling the pots into the soil in an out of the way area will work, as will piling a generous amount of mulch around the pot/root zone. Bubble wrap is a pretty effective insulator as well. Or use bales of hay to establish a temporary cold frame and group all the pots together in this area and then stuff with fallen leaves or other mulch. even some loose hay.

But do NOT bring them inside for winter!