4 season balcony garden

(Question)

My Regent Park condo is on the 21st floor, west facing so has strong afternoon sun. I would like to plant evergreens in containers so it looks a little less gloomy next winter. What suggestions do you have for types of plants and winter care?

(Answer)

Thank you for contacting the Toronto Master Gardeners.

Balcony container gardening is very popular, and there are hundreds of resources for you to review. There are just a couple of things to keep in mind with balconies & terraces:

Check with your Property Manager or Condominium Association prior to installing planters or window boxes.  There may be site specific regulations.

Wind consideration: Is the balcony sheltered or exposed to prevailing winds or wind-tunnel effect? Wind is perhaps the biggest challenge to balcony gardening–wind will dry out the soil in containers easily–consistent and effective watering is required. And the higher your balcony is from the ground, the windier the conditions.

Size of containers: If you plan to grow perennials, you will need large enough 4-season insulated containers that will withstand the changes in temperature throughout the seasons. Note: You should check with your building management for regulations in use of balcony space–safety concerns and weight considerations. For perennials, containers will need to be at least 40 cm. (16″) in height and width. You may need to consider lightweight alternatives for containers and soil.

Overwintering perennials in containers is one of the biggest challenges faced by container gardeners in our zone, and balcony gardeners in particular.  The freeze-thaw cycle is the main problem; that is, the melting of the water in the container’s soil during sunny or warmer spells, followed by freezing when the temperatures dip again.  This is what kills a plant’s roots over the winter.  Your most important starting point is the container itself: it should be as large as possible (the more soil it can contain, the more insulation it will provide. Ensure that the containers are freeze thaw   resistant.  Ceramic and clay pots will probably crack as will cheaper plastic pots.

‘Right plant, right place’ is even more important on a balcony than on the ground–one must consider the recommended growing zone for perennials; select plants that are at least 2 zones hardier than the normal zone [i.e. for Toronto (zone 6a), plants should be hardy to zone 4].

Lots of varieties of evergreens work in planters,but dwarf varieties and those with slow growth are the easiest. This link might be helpful: https://www.bbg.org/gardening/article/dwarf_conifers_in_containers

Lastly there are a number of archived posts in our website, simply type ‘balcony gardening’ ‘evergreen for containers’ in the search bar located to the right of the page. You might find  Evergreens in containers and Growing Emerald Cedar in Container useful.

http://torontourbangrowers.org/img/upload/BloomingOurBalconies.pdf provides some excellent  information.