Balcony gardening


We are moving from a house to 33rd floor of a Toronto apartment building with large east-facing balconies. I would like an “event” for something like this, including construction of sub-irrigation planters (plastic totes inside custom-made wooden planters), planter insulation (ISO or batte?-how much) so perennials can be overwintered on site, other problems (there is already lots on plant selection). I think this gardening would be very different from container gardening at ground level. Thanks. Janet


First it is a good idea to check with your apartment/condo for rules on keeping containers & plants on your balcony.

The balcony’s exposure is the most important thing to consider.  The higher up you are the colder & windier it will be.  The 33rd floor is pretty high up, so you can expect the conditions to be similar to Zone 3-4.  The benefit of rain can be hindered by an overhang from an upstairs balcony. There are products available on the market that you can mix into the medium to hold moisture. This will help having to water twice a day. An eastern exposure will mean sun in the morning but shade in the afternoon & evening so choose plants accordingly.  Drainage is important.  A good planting medium is crucial.  Planters should be a minimum of 22ins deep.

Information regarding “sub-irrigation planters” can be found on the internet.  A Google search of the terms with the addition of the term “construction” will retrieve several articles including two at, they should be useful.

You can make your own or purchase wooden planters and line with rigid insulation which is at least 2ins thick and cut to size.  To overwinter plants one needs to avoid the freeze/thaw cycle.  Difficult in containers on a high balcony but the insulation should help.  You can also surround the planters with bubble wrap. Before winter arrives group planters together close to the wall to benefit from the heat of the building. Avoid using terracotta pots which look attractive, as they crack and the soil drys out real quick. in them.