For those (like me) who won't give up on the idea of getting their own outdoor AVOCADO TREE in Vancouver, CANADA or Reyjkavic, ICELAND, here is an obvious idea that hasn't been floated about: Why not put up a simple, inexpensive, portable greenhouse?
This can be done for less than $100 USD.
(I know of at least one example of a simple, easily-assembled 2-meter high portable greenhouse that can be purchased online for less than $100 [worldwide shipping is available, but costs extra]).
Considering the fact that I paid $81 each for my two "Cold-hardy" Avocado trees at a local nursery (Stewart and Mexicola Grande varieties--both cold-hardy to -7°C), $100 is a reasonable price to pay to ensure that my trees will survive and produce fruit for many years to come, here in Vancouver, CANADA.
The advantage is this: Once you have a nice little greenhouse like this, you could use this to have some dedicated space for your Avocado tree in your yard or garden. And, even if we were to have a record cold Vancouver winter where it gets -20° C (-3°F) during the winter (the actual all-time record Vancouver winter cold was -17.8°C (0°F) in 1968 and in 1950), you could easily keep your Avocado tree alive if it were a good, "cold-hardy variety."
(This idea could even possibly be used to grow Avocado trees in Alberta and Eastern CANADA. The only difference, is that during the really cold freezes, you'll have to work a little harder to keep it above -7°C in your little portable greenhouse.)
Here's an example of how you could achieve this:
Let's say that on a cold winter's night in Vancouver, it will get -20°C (-3°F). If you have a cold-hardy Avocado tree that will withstand -7°C (20°F)(ie. Stewart or Mexicola Grande varieties). You can easily set up some sort of source of gentle heat to provide some partial warmth within your tiny greenhouse that will raise the inside temperature to at least -7°C, so that the Avocado tree within it will survive the deep freeze outside. (You don't have to raise the temperature in the greenhouse to be above freezing. You only have to raise it enough to prevent the Avocado tree from dying)
Possible sources of gentle heat: 1. Heating mats, 2. electric blanket(s), 3. Christmas lights (the old ones that give out some heat — not the new LED lights)
One advantage of planting your Avocado tree outdoors and then having a nice little greenhouse surrounding it, is that your tree would be able to grow much larger than it would if you were to keep it in the house (in a large pot). Obviously, by being in this greenhouse, your Avocado tree would now be able to grow up to about 7 feet high on one side, and would be able to produce up to 75 or even 100 fruits in a good year. This would be plenty of fruit for 1 family. And would even give you enough to share with a few friends.
Another advantage is that, by having the greenhouse around the Avocado tree, it will blossom earlier in the year than it normally would, and would therefore produce a crop earlier in the season than would otherwise be possible. For clever people who have enough space in their yard or property, they could set up 2 or 3 of these greenhouses, and plant different varieties of Avocado trees, thereby giving themselves varieties that will ripen at different times. That way, they will extend the timeframe where they can go outside and pick a continuous supply of fresh Avocados in Vancouver (or Reyjkavic, or London, etc).
This harvest season could begin as early as August with some varieties and continue into December or later for other varieties.
Really, the sky's the limit. And it's so easy to accomplish!
What's stopping you?
--George Stancliffe
