Planting on high is not for the faint of heart. Balcony gardening is difficult and confusing and we don't see nearly enough of it. But that doesn't mean it's impossible.
John Broere and Mark Gomes of Toronto-based Box Design/Build ( http://www.boxdesign.ca) are balcony specialists. They are astonished at what will grow on a balcony. If you like a plant, go ahead and use it, they advise, but keep in mind the exposure you have and how much wind you'll be facing. They have seen a wind whip all the soil right out of a container.
Catering to a wide range of balconies and terraces, Box builds modules that can be installed quickly and removed easily. The boxes consist of a high-density foam with a skin of concrete, so they are light, winter-resistant and handsome. Their depth - a minimum of 22 inches - solves all problems with root systems, keeping them protected and frozen over the winter so there is no freeze-thaw damage. It's the drainage that counts, Broere and Gomes emphasize. That means you have to have a good watering program (once or twice a day) and a good planting medium.
Here are a few more suggestions on how to make a real garden out of a small and difficult space.
Think of the balcony as a way to frame a view. It should look like a tapestry or a painting from the interior of your apartment. If you sketch out a plan with this in mind, you will quickly develop a vision of what the balcony garden will look like. Create a palette that harmonizes with the interior or makes a pleasing contrast.
In terms of exposure, the most important factors when making plant choices are the wind and the sun. The higher up you are, the colder and windier it will be. As obvious as this may sound, many people forget that wind is even more devastating than relentless sun.
Western or afternoon sun is hotter than any other exposure. A northern exposure offers full shade. The amount of overhang you have will also play a part in your choices of plants - you won't be getting the benefit of rain.
Unless you are putting in humongous planters, don't worry about excessive weight on your balcony. What you can schlep upstairs and on the elevator will dictate the size and weight of your planters. Drainage, on the other hand, is a huge issue.
To ensure good drainage, choose as large an array of containers as you can lug or afford. There are some terrific deep-based ones - such as those offered by Toronto's Barracuda ( http://www.barracuda.ca) - in which you can place stones or water to prevent them from tipping over.
Make sure, too, that you don't have anything up against the railing that kids or animals could use to climb up on.
If you are using terra cotta pots, put them on risers (bricks, boxes) so they drain properly; install a variety of heights with the biggest at the back (and closest to the railing) so smaller ones in the front are protected from the wind. And make sure you have a place to store them in the winter.
If you want to leave them out permanently, line planters with 1/2-to-2-inch sheets of Styrofoam that will absorb moisture and save them from freeze-thaw shattering.
Finally, consider creating your own shade. Trellisage looks good, but you typically have to check with your building's management to find out how high, how much and where you can place it. Box Design/Build usually establishes them in large containers set against the dividers between balconies so that they are anchored and won't blow over. It's best to get a professional to do this for you.
When planting, ensure really good drainage by adding packing popcorn, sand or even gravel in the bottom of a container.
Cover whatever you use with horticultural cloth, add a layer of SoilSponge (this will help hold in moisture) and then fill with potting soil.
Add a handful of SoilSponge or any coir product (but avoid using peat moss) to the top layer. Plant normally and water until it runs out the bottom. Do the latter at least once a day.
Plants that are best for wind and blasting sun include any succulent (such as aeonium, echeveria, sedum, aloe and agave) or silvery plants (such as perovski, caryopteris and lavender).
Ornamental grasses are designed to rustle in the wind, while bamboos are great container plants, so try any available. Shrubs and trees - especially many evergreens - also work well on terraces.
For shady spaces, hostas do really well in containers but vary the colour and size. Don't go for huge ones such as Sum and Substance or Francis Williams as they are just too big. Heucheras, ferns and, of course, any of the hundreds of annuals now available (especially Plectranthus Mona Lavender) also make good choices.
In addition to solid yet lightweight pots, a wonderful trowel, a good pair of secateurs and a small pair of Japanese scissors for nipping off dead heads are essential.
If you can't get a tap installed outside, then you'll have to get the water there somehow.
Consider an Indoor Plant Watering Kit for $42.35 from Rittenhouse ( http://www.rittenhouse.ca); it attaches right to the sink and has 45 feet of coiled hose, which should be long enough to reach the balcony.
Also, give yourself a lovely halo of light defining the balcony (Rittenhouse's Aurora Glow String Solar Lights sell for $52) and somewhere to store things: One of the cleverest designs I've seen is a bench with a cushion on top for seating and inside space for all your gear.
Marjorie Harris is editor-at-large at Gardening Life magazine.
Top plants for balcony gardens
Succulents (such as aeonium, echeveria, sedum, aloe and agave) or silvery plants (such as perovski, caryopteris and lavender) are resistant to wind and blazing sun.
Grasses - including golden-toned Hakonochloa macra Aureola, burgundy Panicum Prairie Fire and Schizachyrium scoparium Prairie Blues (a native blue grass) - look great, are tough and rustle in the wind.
Shrubs and trees
Viburnums, Sambucus Black Lace, Cornus kousa (pagoda dogwood) and evergreens such as pines, hemlock, dwarf blue spruce and Japanese junipers are both beautiful and hardy.
Hostas and ferns
For shady spaces, hostas do really well in containers, but avoid varieties such as Sum and Substance or Francis Williams, which are just too big. Heucheras, ferns and any of the annuals now available (especially Plectranthus Mona Lavender) also are good bets.