I live on the second floor in an apartment building in New Hampshire, USA. On my covered balcony I have outdoor plants and bonsai trees in pots that are now all dormant.

What I have done to protect them from dying in the 10F degree weather is to have all of them covered with snow.

I've carried up to my apartment's balcony is about 7 big garbage bags of clean snow. I've empied all of the snow on ALL of my potted plants that are now in their dormant stage, and the snow acts like a great insulator, protects the roots from freezing and crystalizing. I can't even see the tops of my bonsai trees. Just a big pile of snow.

To prevent the snow from blowing away, I have sprayed/misted the snow with water that created a nice shell of ice on the snow.

What species of plants do you have on your balcony? Are they winter dormant, or all year green?

Wowzers. I guess I didn't have to carry snow up to my balcony afterall. It snowed close to 4 inches of snow PER HOUR (with lightning and thunder) today for about 4 straight hours.... for the first time (because of the 50 mph winds), the snow made it onto my balcony without me having to "truck it in" myself like I've been doing with garbage bags. Looks like my outdoor plants in containers on my balcony are going to be very well insulated against the cold for a while....being buried in a few feet of snow drift.

Anyone else use snow to protect their dormant potted balcony plants in the winter time?

Dave

zone 5b

Yes, but only when we have snow. We have a bit from a small storm on Friday, and my balcony plants (bulbs, daylilies, coneflowers, salvia, and yarrow) are all "hiding" under the snow in their pots, so that should protect them to some level.

Down here in zone 7, we don't get winters as bad as zone 5, but we also have less snow to use as a protective blanket. Still, the snow is a good idea when you have it.

The snow, like any insulative material, is only effective when it serves to trap heat from an extraneous source, that being the earth or a heated building in your case. If some quantity of heat is conducted through the balcony slab from the building, the snow could/would help. If the balcony is thermally isolated from the building, snow would be largely inneffective except as a guard against dessication. It would serve to increase the lag time (time it takes for container soil temperatures to adjust to ambient temps), but even that wouldn't guarantee that soil temperatures wouldn't eventually equalize with air temperatures.

Al

Balcony gardening can be done with certain extra care given to the containers.

Before the soil goes into the container, line the container sides with styrofoam. When winter's frost hits the plants, put the whole container into (or surround with, a plastic bag into which you surround the container with bubble insulation (from electronic purchases) or styrofoam pieces.

Or....remove the soil when the plant is dormant, turn the contianer with the plant in it, over....or with the soil in it, turn the container onto its side. Water that might be in the soil and drains on warm day, will run out...and not affect the freeze/thaw cycles.

When turned over, one can insulate further with plastic bags...or two...or three....and put a further cover over it with a bushel basket/picnic hamper....and further cover with burlap.

The biggest problem to plants on balconies is the wind.
If we can put the plant somewhere out of the wind...and do the insulation, we can pretty well rule out damage that way.

Any snow cover is just gravy on the meat and potatoes.