If you leave your plants out until the cold kills them to the ground (or top of the container in this case) most should do fine in a cool basement. It would be a mistake though to keep them under lights for reasons Al mentioned.

Either keep growing them (as in the case of the herbs) or let them sleep. The best practice is going to vary plant by plant. The sage you can grow as a houseplant, the strawberries I would think you could leave outside. What zone are they hardy to? Those might be something to put in the garage too. I dunno, the only strawberries I ever grew were the kind you couldn't kill. Heck, I still have some growing along the fence in the backyard and I "killed" all my strawberries 3 years ago.

Anyway, you really need to type overwintering into google and read up on each plant because what they actually need is going to vary.

I try to get perennials that grow in my zone. The less I have to mess with them the better.
My mother lives next door to me. She has a basement. So I keep the cannas & tuberose (in their pots) over there.
The callas & dahlias I dig up, sprinkle with bulb dust, put in a shopping bag & they spend the winter at Mom's too.

Everything else stays out in their pots.

Nancy

For the containerized true perennials, such as strawberries, dig a hole in the ground and sink the pot in it up to its rim, and fill in the earth around it. That way, the plant has all the benefits of being in the earth for the winter, and in the spring you can lift it out again. (Or, you can remove the pot from the root ball, and plant the root ball for the winter and lift it again in the spring.) You see, what often kills containerized perennials is the freeze-thaw cycle that takes place in winter. The ground will thaw and abruptly freeze, breaking the roots. Then the plant gets water-stressed and dies. You can also alleviate this problem by buying larger pots and adding a layer of insulation to the inside of the pot (like foam insulation) before putting the soil and plant in. This helps to eliminate or slow the freez-thaw cycle, by allowing the pot to freeze and stay frozen during brief thaws.

Hi, Don. Perennials are plants that live for at least three annual growth cycles & include many plants that might not survive the buried pot treatment. Nearly all houseplants are true perennials. Also, containerized plants are actually less susceptible to root damage by freeze thaw cycles than in situ plants, especially those that are newly planted. They are, however, more prone to actual freeze damage than their in-ground counterparts unless we take steps to moderate the actual root temperatures. It's not the freeze thaw cycle that is of danger to containerized plants. Freeze/thaw can happen dozens times with no ill effects. It is the single exposure to temperatures below which the plant is not genetically programmed to withstand that does the plant in. When temperatures drop so low that intra-cellular water freezes, tissue dies.

I suppose there are instances when newly planted (in situ) perennials have begun to establish roots into the surrounding soil are heaved by frost, breaking a few roots, but root breakage is not the primary concern. Instead, instances where the plant is heaved out of the ground and root death from root tissues having been exposed to dessication or freeze injury are of much greater consideration. Though root breakage might possibly occur occasionally in in-ground plants, it would be a virtual non-issue in containerized plants.

Insulating a container is of little value unless it helps retain heat transferred to the container from an extraneous source. If the container sides were insulated, the top mulched, and the container was sitting on the soil, it would help to retain some heat from the soil. The same would be true if the container was situated against a heat source (building, e.g.) and the side against the heat source was not insulated, but the remaining sides were, it would also be helpful in retaining heat. Without an extraneous source of heat, insulation serves only to moderate the speed with which temperatures change inside the container. Lows would likely be the same lows & highs the same highs, it would just take longer for container temps to equalize with ambient temps.

Al

I bring my potted containers into the garage - and my weather is similar to yours. I've overwintered some surprising things but don't forget to give a little water during the cold dry months. I think your strawberries would do fine outside. Growers in our zone have strawberry fields :) If you're really concerned, sink the pots in the ground and mulch with leaves. My lesson learned for last year was that I turned containers on their side next to the house and some were near a dryer vent. I lost containers of ice pansies, dianthus and even sedum Autumn Joy because of the freeze/thaw the hot air caused. duh - should have known better. I have enormous deck pots of hosta that did not return well because of that also. They all have done great in the past going into the garage.

Thanks for all the advice -- I think I have a plan now and if I read everyone correctly, I don't need to provide light but keep the containers from drying out and not getting too cold. My garage seems perfect in that it usually stays about 20 degrees above outside temps so until January when we can sink into sub zero temps, I'll keep them there and then move them to the basement until next spring. Hopefully that's enough time for them to think they've been through the winter and the basement stays around 50 degrees during the cold months. With gas prices this year my entire house may remain at 50 degrees as well. :-)

I was able to propagate the first year strawberries I got from a neighbor into 9 containers and I'm going to diversify leaving a couple outside, a couple using the garage method, and a couple I'm going to let grow under my winter lights inside and see what happens. I haven't had any luck leaving tender perennials outside, perennials that would normally survive in the ground, in pots but things like chives, mints, and oregeno seem impervious to the sub zero winter temperatures here so their cells must be extremely hardened to protect them from the cold.

I can't use the burying the pot method because I have absolutely zero yard. My entire garden is on two rooftops and everything is containerized -- thus making things a little more difficult when overwintering. To keep things cheery during the cold, short days of winter months, I have two light rooms, one using florescents for vegetative growth plants and one HPS system for flowering stuff. Amazingly, last year I overwintered a chili pepper plant under lights and that plant was a huge producer this summer due to its starting size when I brought it outside last spring. So the pepper plant didn't mind living through an artificial year but normally, in my zone, pepper plants aren't supposed to make it past one year. This winter I'm putting the habeneros under lights too and will try this with about 6-8 plants.

Thanks again for the advice and now I have a game plan and I'll let everyone know next spring how it turns out.

Have been reading, with interest, the ideas on overwintering strawberry containers and have decided to move them into a storage shed attached to my apartment and we'll just have to see what happens. I, like someone else, have zero yard so burying the pots is not an option. Thanks for all the great ideas.

I've never moved my plants inside to overwinter them. They just die back naturally and come back again in the spring. The only things I dig up and bring in are cannas.

I have a patch of perennial strawberries that do quite well here in the Fairbanks area. This fall I brought in a planter of Quinault-type berries that had a late start. I left them outside as long as possible and then brought them in. They've continued to ripen & flower but have no taste. So I'm about to move them to a cold spot that doesn't freeze. These are usually annuals here, and the type of planter wouldn't allow them to be set in the ground anyway (a moot point since its already frozen). I'm hoping that by cutting off all blossoms and giving them a resting period that I will be able to revive them indoors in the spring. Any ideas?

A cold spot that doesn't freeze should suit them just fine. An extended rest at temperatures between freezing & about 45* F. would be great.

Al

I think earlier someone asked about which perennials might survive in pots:
I had placed a couple of pots of mums on the ground up against the garage last fall. I covered them with plastic bags full of leaves. When I uncovered them last spring, they were still alive but had some mold on them. They survived and flourished on my deck this year. I also had one that I just put in the garage in its pot. It survived and flourished too.

This year, I'm going to do the same except for the plastic bags. I'm going to just pile the leaves on top. Anyone have a suggestion for what to use between the plants and the leaves? (The leaves are chopped up pretty good.)

Never thought I'd think of something I'd use packing peanuts for, but this sounds like a good spot for them. If you choose to use them, be sure they're not the biodegradable type.

Al

october17, you could wrap them in bubble wrap and stuff wadded up newspapers in any open spaces between pots before burying them in leaves. Also, don't cut off spent growth until new shoots appear in spring. That's the advice I got on how to overwinter mums outside in pots.

Barbara in Virginia

Thanks Plays in Dirt. I didn't cut them down, just laid them on their sides and buried them in leaves - a mound about 2 feet high. I did however cut down some mums that were growing in our whiskey barrels. I cover the barrels with plastic every winter (to conserve the soil nutrients). The mums in the barrels were cut very short and covered. We'll see what happens there. I also cut down a hechura and a columbine, then covered them. They were very healthy and still green, so I don't hold out a lot of hope for them. It's just an experiment. Let's hope for a mild winter!
Oh, last year I did have sucess with overwintering two staghorn sumac in containers (uncovered). Don't know if you're interested in those Mea. They are really pretty in the fall and tropical looking all summer and some interest in the winter too. I think I even had a sucker in the barrel!

Since this thread has resurfaced, I'll add a word. As Al and others (babywatson) have said, perennials count on cold dormancy and need a lot less babying than you'd think. Small ones die back to the soil line, then pop back up in the spring, big ones act like trees, and some of us have no options about taking them in, burying them, etc. The only ones I worry about at all are roses, which are notoriously finicky, but when I am sensible about the varieties I buy (not always!), mulching and reasonable attention carries them through. Shade is good in early spring because of the freeze-thaw cycle. Early spring is the *most dangerous* time--especially for evergreens--in my experience.

I grow mine on a balcony, and am planning on using plastic attached to the top and bottom of the balcony to create a warmer space. (it would be completely enclosed by the plastic other than a small hole for my cat)Would that be suffuciant on its own, or would I need to try and get the plants as close to the house as possible or wrap the pots in something?

I have roses, lilacs, some herbs, and assorted bulbs (tulips, dafodils, gladolias) out there. They are all hardy to or below my zone.

Also, how much water do they need during the winter? We don't often get snow, so I can't count on putting snow on top for moisture.

Marie, I am close to you in area and I don't do anything special for my containers over winter UNLESS they are predicting a serious cold spell. Then I do congregate them together and close to the house. Otherwise, they deal with whatever comes their way. I have a LOT of containers, most of them permanent plantings, and with the exception of some annuals, I've lost nothing over winter. In fact, a surprising number of annuals (actually tender perennials commonly sold as annuals) will overwinter better in containers than they do in the ground.

Unless they are sheltered from rain, there should be little need to water them. Our typical wet winters will take care of that and even in rather extended dry spells, evaporation is slow due to colder temps so I'd check to make sure they are not too dry only. More plants are lost to wet roots than to cold in our climate. In fact, I often move certain types of container plants to a drier location so they don't receive TOO much natural rainfall.

Yes, they are protected from rain - I have completely enclosed my 2nd story balcony (which means that they get cold from underneith too) in 4 ml plastic. Mainly I'm concerned about my roses - I've heard they can be a pain to get through the winter in a container.

The plastic also serves to give me a less cold place to go smoke outside LOL