Overwintering containers

paulsiu(5a)April 5, 2012

So on a separate thread, I am told that overwintering container plants are not the same as overwintering plants in the ground. I assume this is because the ground act as a thermal sink so that it smooths out the temperature change. Previously I overwintered sedium in pots without any issues, but sedium are really hardy and probably didn't care about the cold.

So what should I do in the winter with container plants. Should I stick them in my unheated garage? I assume even though it's unheated, it's still warmer than the outside.


Thank you for reporting this comment. Undo
terrene(5b MA)

Paul, can I ask why you are asking this question when we're just coming OUT of winter? :)

The ground temperature is much warmer than the air temperature on the coldest days. That why they say that container plants should be at least 2 zones more hardy if they're left in the containers over the winter.

An unheated garage is okay - I put some Salvia Black & Blue in there this past winter, and it did fine. Watered it once or twice. But most of my pots are put on the east side of the house, under some shrubbery, with bags of leaves or mulch surrounding the pots, and a layer of leaves on top, to shelter them from wind chill or temperature extremes.

    Bookmark   April 5, 2012 at 7:07PM
Thank you for reporting this comment. Undo
katob Z6ish, NE Pa

sedum really is hardy. I had a division of autumn joy that I put down on some concrete steps and then forgot to replant..... for two years. It even put out some small blooms in the fall, even after most of the soil had washed away from around its roots.

yeah the unheated garage works fine, it keeps the plants safe from all the up/down temperature swings.

    Bookmark   April 5, 2012 at 8:50PM
Thank you for reporting this comment. Undo

Well, I plant to start planting some plants in a container so I am thinking ahead to see if I can overwinter them.


    Bookmark   April 5, 2012 at 10:30PM
Thank you for reporting this comment. Undo
northerngirl_mi(Z5 MI)

Three things can cause problems for overwintering plants in pots outside...

  1. temperature - as noted, best success is with plants good for one or two zones colder than you... Also, larger pots are better than smaller pots. Also, temperature swings... when it warms up for a few days, the pots warm up faster than the ground, and plant may come out of dormancy prematurely... then a cold snap... you can end up on a see-saw... I put pots on the north side of the house for winter so they stay a more constant cold.

  2. drainage/moisture - the soil freezes, and then the lip of the pot holds any extra mositure... this can cause rotting. Alternatively, you can tip the pot on its side.

3. critters - if you put leaves/pine straw, etc around /over your pots, sometimes voles / mice will nest there, and try to feed on the roots in the pots. (I've never had this problem, but others have)

If you go for the garage, you will still need to manage moisture... don't let the soil get dusty dry - you may need to add a bit of water every month or so, but do not overwater...

You can probably make many plants work, so long as they aren't fussy, and you're willing to do a few extra things.

Z5 northern MI

    Bookmark   April 6, 2012 at 10:01AM
Thank you for reporting this comment. Undo

I've read that containers take away about 2 zones of hardiness. If you stick with things that are hardy 2-3 zones north of you, you can probably overwinter in large, weatherproof containers without doing anything special. Plants that are only hardy to your zone you will need to protect more with some of the methods discussed above.

    Bookmark   April 6, 2012 at 11:57AM
Thank you for reporting this comment. Undo
ken_adrian Adrian MI cold Z5

bottom line..

you are too much of a neopyte.. to mess with pots ...

its like you want to start with the masters degree.. before undergrad ...

so the simple solution ... is plant a veggie bed ... how that for a tangent.. lol ..

in october.. when the veggie are all done.. clean the bed.. dig a trench ... and unpot.. and 'heal in' .. the plants.. and let mother nature take of them for you ...

as those above note.. its too much water in a pot in winter [wrong media or dirt] .. the garage being 2 zones warmer.. those 60 degree days in february.. when the garage hits 80.. and then that night its 20 below again ... and the fact that they come out of dormancy 2 or 3 months.. before they can go outdoors in z5 ... so you end up keeping the pots in the garage until near june..

this warm late winter .... is a prime example of why pots can be so problematic in z5 ...

and even better than healing them in.. is to plant them in permanent locations .. come September .. and be done with them ...


    Bookmark   April 6, 2012 at 3:46PM
Thank you for reporting this comment. Undo

Veggie bed is a bad idea. There are way too many garden pest. I just saw a rabbit size of a large cat. The veggies would have to live in a chicken wire cage.

Will try one container of perennials and do annual for the rest.


    Bookmark   April 7, 2012 at 12:23PM
Thank you for reporting this comment. Undo
diggerdee zone 6 CT

I overwinter at least 100 pots in my garage each winter, (at one time had 243) although the number is dwindling (but not as fast as I want it to!). They range from pots that are 24 inches in diameter to 4-inch pots to lily crates. My garage is unheated, and quite cold. I cover the windows to keep out the sun (which isn't a big deal as the windows face north and east), and I water the plants well before bringing them in, with maybe one watering (or shoveling of snow on them, if there is any snow) before bringing them out.

IMO, the tricky thing is knowing when to bring them in, and when to bring them out! You want to make sure they are dormant when you bring them in. This winter, honestly, most of the pots didn't make it in the garage. It was warm out until late-January, and at that point I didn't really bother, although I have in the past brought them in in January. This year the garage was too messy and I was too lazy, lol.

If you want to keep things outside in pots, for winter interest (evergreens, etc.) then I would go for something at least a full zone hardier, if not two. I did that one year with some red twig dogwoods and other small shrubs and it was nice to have them on my back patio.

Experiment with some hardier perennials if you want to try it first before committing to a lot of stuff. Daylilies, peonies, daisies, echinacea, hostas - these always come through with flying colors for me here in zone 6.

Good luck!

    Bookmark   April 7, 2012 at 3:03PM
Thank you for reporting this comment. Undo
ken_adrian Adrian MI cold Z5

Veggie bed is a bad idea. There are way too many garden pest.

==>> are you missing the point.. or irritating me on purpose.. lol .. either is approved ...

you have a DEDICATED AREA ... for healing in plants in the fall ...

the veggie idea.. is just an alternate season use ...

i used to have an area behind the garage at the old house ... for just such winter healing ...

it was only about 6 by 4 feet.. you can stick a lot of stuff in a very small area.. since you intend to repot in spring .. before growth starts ... [and you might want to lay some hardware cloth over it to protect from vermin ..]


    Bookmark   April 7, 2012 at 6:17PM
Sign Up to comment
More Discussions
Elk in Dogs for mrtulin
The link is in here scroll down and have fun. Some...
Patty W. zone 5a Illinois
spring things
replanted this as part of last years back garden renovation...
Dieing Elephant Ear?
I bought a Black Magic elephant ear about 4 months...
What groundcover would you mix with Helleborus?
I'd like to plant a new bed of hellebores, but I'm...
magpiepix 5b/6a
anemones was a better name
Sponsored Products
Tender Ecru Wallpaper R1773, sample
Walls Republic
Tiffany Style Victoria 25-inch Table Lamp
Double Equal Rectangular Stainless Steel Kitchen Sink
MR Direct Sinks and Faucets
Steelcase | Amia Upholstered Office Stool
SENCHA Tea Maker by Blomus
$96.29 | Lumens
MaxLite ELLF270UN50 MaxLite StaxMAX LED Flood Lights
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™