Weird, I thought I replied to this message yesterday. Anyways. . .
why would you want to add clay to your potting mix? No one likes clay in their dirt! I would think it would be especially bad for containers, as it would compact things. The best mix for pretty much all plants (so I've heard from someone who would know), is 1/3 sand, 1/3 peat moss, and 1/3 black earth (dirt). You could probably also throw some compost and/or manure in there.
Don't add worms. The common nightcrawler (earthworm) needs cooler temps. and an extensive tunneling system in order to survive. And the red crawler worms used for vermicomposting would multiply too quickly, unless you also had lots of frogs eating them. That's not too likely on a balcony, unless you keep them as pets. You shouldn't need worms to aerate the soil if your potting mix is open enough.
I don't know of anything that will survive winter on a balcony. Living in zone 5, you'd probably have to look for plants that are hardy to zone 2 or 3, and then they may have a chance. I think the problem is that the entire root ball freezes solid because there is less dirt (and snow) to insulate it, so the plant dies. I could be wrong on this though. Someone here grows lilacs on their balcony, so hopefully they see your post and tell you more. Hydrangea is not likely though, since they aren't that hardy to begin with, and set their flower buds in the fall, so you may never see flowers if they all freeze and die over winter. Hostas are worth a shot, since they're quite tough.
I can't imagine not wanting a huge garden. =) I'm so frustrated with my little balcony and not being able to grow perennials! I guess the grass is always greener on the other side, eh?

Sahoyaref - that would be me with all those Zone 3 & 4 shrubs out on my balcony. LOL Others have been trying them now too.

For example - my lilacs are Zone 3/4 as are my blueberries (northern highbush). They looked like this the day before spring this year when it had the nerve snow:

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They looked like this yesterday:

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Some other hardy shrubs include the "pee gee" hydrangeas (ie., Hydrangea paniculata 'Grandiflora' or 'Tardiva' or 'Limelight', etc). These are hardy to Zone 3 and here was mine yesterday (still a baby but I am going on the 3rd year growing it):

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My peonies are supposed to be hardy to Zone 2/3 and I have the old fashioned popular "Sarah Bernhardt" here:

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I bought it last spring as a plant in a small pot and potted to the larger container (it had 3 buds but they never opened, which I figured would happen). This year it has 5 buds that are swelling so I am hoping they will open. It's tricky because of the sun issue, but right where they are sitting, they get morning sun right along that rail from sunrise (which is about 6 am now and will be an hour earlier next month, until about 11 am, when the sun goes up over the building).

I have asiatic lilies that are also Zone 3/4 and this is the 4th year in their pot. They're coming up now:

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I have some tiger lilies that I tried for the first time last year and they are not up yet, but they are later bloomers (mid-summer), so they have some time. I saved some little bulbils from them last year and planted them in a little plastic pot that sat outside all winter. A bunch have started leafing already! LOL

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I have some old old hostas dug from my mother's yard (I don't even know the name but they have a light lavender flower and plain green leaves - the plants were originally planted in the yard over 35 years ago). I have had them about 6 years in the same container and they are hardy to Zone 3:

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Because alot of people who ground-plant them have problems with slugs and underground animals like voles that chew on their roots, they have taken to planting them in containers and sinking the pot. But other than that, they are pretty tough and come in all sorts of leaf shapes and colors, with large or small flowers in white or lavender or purple, some even fragrant.

I also have 2 clematises - both are jackmanii types - a "Prince Charles" and a "Madame Julia Correvon". These are also Zone 3s and I have them in a large 21" container. This is the Prince's 4th year and he has already gone nuts. It's Julia's first year after a winter and she is sprouting from the roots. Here is what they look like now:

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I have lily of the valley plants that are hardy to Zone 2. Their foliage is all up and I'm waiting for the bloom stalks. They looked like this today (I have a couple containers with them):

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So there are plants out there that one can try in the colder zones. In my case, I don't have to protect them except some mulch. But these could get some protection in areas where they would be marginal in a container just by placing them back against the wall and perhaps placing them in one of those foam ice chests and packed with more foam, the issue being that when the roots freeze, they should stay frozen and not be permitted to continually freeze and thaw. Ie., for hardy perennials, the roots CAN freeze (and inground they do), but they will need to stay frozen and then be allowed to slowly thaw into spring because freezing and thawing and then refreezing and thawing will do the damage and can kill (the root plant cells can burst).

I have a bunch of shrubs that are more marginal for me - Zone 5/6 in containers, and they generally do okay once established, eg., my weigelas, that I haven't had any problems with, although sometimes I'll lose some small stems to bud blast, but those are easy to prune off. The toughest are the evergreens, which I have to put wind breaks around, etc.

Wow, Jenny! You have a lot of things on your balcony that I am considering growing! Thanks so much for the information and pictures! I'm encouraged now and will be growing all kinds of things! Your stuff looks green and healthy.

Sheryl - if you hang around here long enough, you won't have room to move. LOL

LOL! I'm not going to start collecting plants for the balcony until after I move. But you can bet that the day after I move in- I'll have lots of potted plants growing on the balcony. I'm moving on Friday. Soon!

Well, I've collected a lot of plants on my balcony now! I have a baby 'Charles Joly' lilac - about a ft tall, a dk pink honeysuckle bush - also about a ft tall, 4 brugmansias - 2' tall, 4 pots planted with various datura seeds, just beginning to sprout, a pot of dk red cannas and a pot of elephant ears - both bog pots, without drianage. I planted larged pink flowered impatiens capensis (touch-me-nots, jewelweed)in these as well since they like bogs too - 8-10" now, I have a big pink bleeding heart, tall white iris, purple hespris (dam's rocket), two pots of hostas, three pots of dahlias - a ft tall, a pot of large purple malva - just sprouting, chives, a florist gloxinia from last year, 2 pots of calla lilies, fuschia, and morning glories planted in the pots with the datura - just beginning to sprout. I want some big ferns too. Do they grow well in pots and will they survive a Canadian zone 5 winter on the balcony?

Three of the brugs of in a very large 2'pot. Can I plant the calla lilies in this pot with them or will the brugs take everything. If I feed the brugs constantly, will this burn anything else I plant in there with them. I'd like to put the fuschia in there too.

I have some more large pots for things, just no more dirt right now. I'll have to get some more for the ferns, if I grow them.

I'm getting a clivia and some hellebores soon from a trade. Will the helebores survive the winter on the balcony here? If that is in doubt at all, I'll bring them in. I know the clivia has to come in. I'm also getting a crown imperial fritilaria bulb from a trade. All these should arrive next week. I can't wait to see the frit in bloom! I also may be getting some dward bananas and white spider lilies from a friend. Not sure yet. Most of what I grow now is tropical and has to be winter stored, but that's okay. I'll put it all at my MILs. She has a great underground root cellar/pump room where her dahlias spend their winter.

LOL

It didn't take long. :-P

There should be a number of hardy ferns you can try. With respect to the Brug, some are dwarf but many can get pretty big. The callas are bulbs and you may need to dig them. They would probably be prettier by themselves. The hellebores should be okay - I've seen various ratings for them but apparently they have been known to survive in colder areas than originally thought. Especially if they are mulched/protected.

Not sure about many of the others which are bulbs but pretty ones though.

You have your work cut out for you! LOL

I realize that most of what I have will have to be brought in for the winter. I don't mind that. My MIL has a good place to keep them for me. But I would like to have a few shrubs/perennials that I can leave out there. I haven't decided if I'll bring in the big brugs or just take cuttings in the fall. I guess it'll depend on how big they get.

I've finished planting my seeds in my containers and have leftover seeds. Is there anyway to keep them for next year?
I hate to throw anything out and I don't really know of anyone who would want them as there isn't very many of each kind.

Alaina - I have kept seeds, even for a few years and they have done just fine. Just make sure that you store them in a dry place so they don't mold. If they are still in a seed pack, you can put them in a paper (regular or wax paper) envelope. I know some people get fancy and store seeds in glass vials, which is another possibility.

i live in z3 in winnipeg and our winters get very cold. i have tons of perennials in my gardens and was wondering if i could take some to grow on my balcony. i am moving into an apartment this spring and want to take some of my perennials but dont know what to do with them overwinter.

From wha tI understand, the plants that will survive out of the ground in pots will need to be two zones warmer than where they are growing. If you have access to a place to sink them in the ground for the winter, that would help. Maybe you can insulate them out of the wind somewhere and that might help them survive the winter, as well.

I'm extemely new to balcony gardening1 Full-Full-sun. What do I do? I don't want anything "hanging" since I would have to climb up there, and Probably fall! What can give me shade and put up with Severe Thunderstorm wind in Spring?

Ditto as to being new and in the sun for me... Southern exposure apartment, and it's looking like full sun all day now that it's high enough in the sky to clear nearby buildings. What size of containers would you veterans advise? I'm handy enought that I'll probably try to build boxes myself (in a friend's garage). I'm most interested in growing herbs and edibles (especially hot peppers, peas, beans, radishes and anything else compact and tasty) so I'd like to be able to plant several different things in one box, if they get along together. Also, has anyone tried to grow a zucchini or other bush squash in a container? I'm hoping it'll work, but not sure if it'll turn out to be a big waste of planting space.

Thanks,
G

PS... pretty short growing season here.

gardengal54
I've lived here for 10 years and this has been my longest stay in any home. I know I'll be moving again someday so I've tried to get prepared.
I've got so many plants in beds that I couldn't bear to leave when the time comes, so I took starts off all my favs and potted them up. Some of them are going on 5 years in pots now and doing fine. When the move finally happens my fav plants and I will be ready.
Anyway, this is the perfect time of year to get starts and you have nothing to lose, so go for it :)
I use Miracle Grow potting soil that has the moisture thingys in it. Works for me.
I grow Salvia, Balloon Flower, all sorts of lilys, Tulips and other spring bulbs, Iris, Succulents, Lamium, Hosta, Bleeding Hearts...well you get the idea. I even have two big containers of baby lettuce that reseeded from last year.

Calgary - if you're still checking in this thread, I am going to try growing some spaghetti squash this year. I have grown cucumbers for years in the past and they did fine. Just be aware that many plants that claim they are "bush" often put out some vines anyway, so you might want to surround the "bush" with a teepee, etc., to try to contain it and consider mulching around the base so you won't have to water as often.

For those in full hot blazing sun, before one of my sisters and her hubby had moved from a blazing sun apartment with balcony and bought a house, she was able to grow some of the ornamental grasses (eg., miscanthus) and bamboo well, asparaghus fern (it got huge), sunflowers, and veggies (although she had to continually water them). I would think the prairie type plants like daisies, asters, etc., can handle the hot dry better than most plants.