The primary problem is freezing. The water will freeze and in and of itself this isn't a problem. It's like a perennial in any other container. Where the problem comes in is the water freezing and expanding against frigid cold plastic and breaking it. I make extensive use of self watering containers, but only for annuals. If I were to try to overwinter a perennial in one I wouldn't fill the reservoir at all, I would simply top water the mix directly and in the winter only if the mix was bone dry. I would try to avoid a completely full reservoir that would just become a big ice cube.

All of those are pretty hardy plants and will do just fine over wintering in pots. I had a bunch of extra plants (daylilies, Heuchera, Lamium, Campanula, Hosta, the list goes on and on) last year that I simply potted up and put behind the shed until the next spring when I could sell or give them away. Sometimes they had snow cover and sometimes they did not. They seemed to do fine. Only things that had trouble with it was Veronica and Iris, both of which presumably did not like being slightly water logged in late winter thaws. A good potting mix would have admittedly been better, but I had so many that I didn't want to go spend a lot of $$ on more bagged potting soil. i just used regular garden soil with gravel/small rocks at the bottom for extra drainage. My plants were on top of the ground and got no mulch or cover. If you want to play it on the safe side you could also find an empty spot in your garden to partially bury the plants IN the pots, up to the rim. I've done that before and it works well- just pull them up in the spring. I think the only kinds of plants that would not to well over wintering in pots are those that are not fully hardy/a bit tender, or plants that really object to poorly draining or overly moist soil. I did find that water sometimes pooled up in the pots when the ground in them was frozen. CMK

Don't overwinter your perennials in garages. Unless it's a open air garage (no walls). Perennials do require outdoor exposure to survive. they do need some moisture and also some sunlight to stimulate growth when spring arrives. So as much as you can ape an outdoor exposure you should. This can be achieved via a coldframe, with hay covering the pots for added insulation. The insulation just helps to keep the temperatures steady = not to warm it up. You may need to vent the frame when the sun gets too warm. Absent of a coldframe, place your pots (grouped together) in a protected spot, away from the wind and the hazzards of winter's freeze and thaw cycles. In our modern suburbs, I've found that the little alley between houses over such a protective haven. I had left my potted shasta daisies, climbing hydrangeas, black eye susans and roses in this area and I've had a high success rate. I hadn't even bothered to mulch them. If you don't have such an area -- place them close to fence corner away from the winds. In addition to heavy mulching with hay or leaves, I also would suggest that you pile up snow. Remember that what you are seeking is simply to steady the temperatures. Now if you cannot find such spaces at all, you can dig a trench and place the pots the ground and once again cover with earth and mulch. - Add snow when the snow starts for added insulation. This is the method used for bonsai trees that require overwintering outdoors. That work out. Ianna

Hi Adam, I'll try to help, but I'll admit to having success with overwintering without really thoroughly knowing why, other than dumb luck, lol, at least in the beginning! Barbara is going to dig up her plants because she is moving in a few months and wants to bring them with her. I'm assuming if she weren't moving, the plants would stay in the ground. As far as your broken door, I honestly don't know. As far as I know, the idea of bringing the plants inside, but in an unheated space, is to get them out of the more severe temperatures in which a potted plant might not survive, but still giving a cold environment in which the plant can go dormant, which is necessary to it's cycle. This is why you cover a plant with plastic, or in my case, I cover the window in the garage with black material. I guess it's kind of a fine line between dormancy and just enough heat/light to keep growing. In my case, I think that's also the reason I lost so many roses last year - bringing them out of dormancy too soon. I think outside, the light doesn't matter because it's cold enough for the plants to stay dormant, whereas in the garage, those few degrees may keep the plant thinking it should still be growing. The other option you mentioned, just digging them in somewhere for the winter, is certainly possible if you want to. There are two ways this can be done. One, plant the actual plant. I choose not to do this because 1.) digging a hole in my yard is a major construction activity and 2.) I have to add so many amendments, and at this time of year I just don't have time to deal with this. If you have an already-prepared bed (which is something I never have, lol!) and want to stick a plant in temporarily, that might be a whole lot easier. The second way is to plant the plant with the pot. In other words, dig a hole and place the plant, still in the pot, right into the hole. I never really got the idea of this, since I figured if I'm digging the darn hole, I might as well just plant the darn plant, lol! But last year I did this with a really late-season, last-minute plant I acquired, and it did work. But I only tried this because it was a rose, and I was a bit gun-shy of doing the garage thing with roses after my experience, so I tried the pot-in-the-hole method. It did work, but I don't think I will do this too often, especially not with perennials, but that's my personal preference. Perhaps if I had a plant or rose that, like above, I really didn't want to lose, I would do it again, but it's so much easier to just drag it in the garage. Lastly, as far as your patio plants, yes, you can drag them into the garage and drag them back out. I do it with my 80 or so plants each year. There's no absolute guarantee it will work, especially with the question of the broken door, lol (which hopefully someone else can address) and with the annuals it's an iffy thing, although I've overwintered some annuals my son bought me at a school Mother's Day sale for five years now! Again, at least with the perennials, the key is timing. Bringing them in after they've gone dormant, and bringing them out at the right time in spring. I hope this helped at least a little. Maybe someone with more knowledge will pipe in and add some info. BTW, George, thanks for that added post. The info on the feeder roots was very helpful. :) Dee