Growing Avocados in a Temperate Climate
What I’ve learnt so far.
Avocados are a subtropical fruit native to the Americas, originating in Mexico and Guatemala. However, they are easy enough to grow in warm-temperate climates like Melbourne’s (provided you can keep the possums off them).
I live in Kyneton, which has a cool-temperate climate. Most gardeners would say that trying to grow avocados here is ill-advised. But I’m trying anyway. I’ve successfully kept a few avocados alive in the ground for two years now. I’ve also killed a few. I’m yet to harvest a single fruit, but I’ve already learnt a lot in the process.
It’s not just about the cold
Our winters are cold, and we have some severe frosts (but it rarely snows). The cold weather can slow the growth and even damage the foliage of the trees, but it’s not the biggest problem I’ve had with my trees.
The biggest killer of the trees has been the heat.
Think about it: an avocado is an evergreen tree. In its natural state it grows in a dense rainforest. Young trees have the protection of an established tree canopy. It is only when the tree grows large and breaks through the canopy that it experiences harsh direct sunlight. Young trees need protection from cold AND harsh sun.
How I protect my avocado trees while they are young
I planted two trees inside my netted enclosure. This is a large space that creates a mild microclimate by reducing wind and increasing temperature. This post on using a thermal imaging camera shows the netting affects nighttime temperatures.
I use internal fencing to create rooms within the netted enclosure. One such room is the chicken run. It is in this chicken run that I’ve planted the avocados.
Apparently, avocados hate root disturbance and therefore aren’t suited to planting in chicken runs. I’ve overcome this by fencing the trees off, so the chickens can’t scratch underneath them. I added poly pipe arches to the structure and have installed 50% shade cloth so that it covers the tops of the trees and the north and west sides. This helps to stop the hot afternoon sun, but allows the more mild morning sun to penetrate. The shade cloth also helps to reduce frost damage.
This protection has not been enough and one of the trees died back to the graft in autumn. The other tree, a bacon avocado, has not put on much new growth at all. So there must be other factors at play.
What avocado varieties did I choose to grow?
I planted two trees in the chicken run “room” of my netted enclosure. I was quite specific about which varieties I wanted to grow. The trees needed to stay fairly small, and be cold tolerant. Avocados are divided into two types (Type A and Type B), based on when their flowers open and their pollination behaviour. Avocados need cross pollination from a different type, so I wanted one of each type to ensure successful pollination. Based on various research methods I whittled my list of candidate varieties down to the following: