If growing subtropical fruit trees on a windowsill is a hobby of yours, growing a potted avocado tree is one of the biggest accomplishments you can tackle. Consider it the Olympic Gold Medal of container gardening fruit, and for good reason. Keeping an avocado tree alive and thriving in a container is no easy task, and getting it to fruit is a whole new ballgame. 

As an avid fruit gardener and a fan of avocados (although not on toast… eww), I’ve experimented and explored in the world of container-grown avocado trees for years – and I can personally confirm that getting an avocado tree to survive, thrive, and fruit in subzero gardening zones is HARD. There was limited information available on the subject when I started, and unfortunately my :trail and error” phase usually ended in error. Losing a rare (and expensive) tree is beyond depressing, and I’ve put in a lot of time and effort to build my knowledge and skill base to keep it from happening again. 

This post is a (very) brief summary of my most critically-important lessons learned (read: failures) in container-grown avocados, shared in hopes that they can provide a starting point for other new gardeners’ success.

Choose the Right Avocado Tree

Starting avocado trees from seed is a widely popular internet fad. Everyone has advice, everyone has their own favorite system, and you can even find cutesy little avocado seed “boats” that take fussing with toothpicks out of the equation. If you’ve ever wanted to start an avocado tree from seed, there are a thousand articles explaining exactly how to do it!

Unfortunately, an avocado tree started from seed is not likely to produce fruit – at least, not if you intend to grow the tree in a container on your windowsill.

In its natural environment, an avocado tree can (and will!) grow to over 60 feet in height. However, a northern gardener can’t just plant the seed outdoors; avocados aren’t cold-hardy trees, and any sign of frost will kill them (much less the subzero winter temperatures of zone 3 and 4!).

For container growing, the only option for growing a fruiting avocado tree is to select a cultivar that is either dwarfing or well-adapted to restricted growth. There are several options available, but these are my top two recommendations:

1. “Day” Avocado: The “Day” avocado cultivar is widely recognized as one of the most container-friendly avocados available. It’s much smaller than its 60+ foot wild cousins, and most nurseries agree that roughly 3 feet is the height at which it may start fruiting. There are a lot of nurseries that sell this variety, but if you are planning to purchase this avocado, I recommend purchasing this avocado from Logees… not because I get a referral fee (which I don’t – I am not affiliated with Logees or any other greenhouse), but just because I like the quality of their plants. Highly recommended.
2. Wurtz Avocado (also known as “Little Cado”): The Wurtz is technically a dwarf avocado tree, but don’t think of it like a small shrub; the tree reaches roughly 10 feet tall. Compared to the unwieldy height of other cultivated avocado trees, it’s easy to see that keeping a Wurtz happy in a container is a much easier chore – but 10 feet is still a lot to handle on a small windowsill. You can keep height under control with some basic management of the tree, but the Day is typically preferred over the Wurtz because it’s easier to get the Day to fruit at a low height.

Provide Potted Avocados with the Right Growing Environment

An avocado is extremely sensitive (ask me how I know… just ask me). For many of the tougher subtropical fruit trees such as the pomegranate, if you don’t provide the right environment, the tree will typically manage to struggle along, and may still even set some fruit. Other trees like container-grown lemons may be more picky; without the right growing environment, the tree itself will still survive, but it won’t provide you with fruit.

The avocado? This tree is the diva of the subtropical fruiting world. Without the right growing environment, the tree doesn’t just drop its fruit – the tree itself will just give up hope and die. This isn’t just disappointing, it’s tough on the wallet. Finding a dwarf or container-friendly avocado tree is a challenge, and it’s extremely important to protect that investment by providing your new tree with the best possible chance for success.

Creating the right growing environment for an avocado is a complicated and complex process, but here are the boiled-down, most-crucial elements I have found important:

1. Watering and Drainage: A potted avocado tree can’t tolerate excessively damp soil, particularly in cold weather. It’s extremely important to use a fast-draining growing medium and to avoid overwatering. Find a schedule that the tree likes, and stick to it.
2. Pot Size: In keeping with the drainage needs, a pot size that is too large for the size of the tree will trap and stagnate moisture. I believe pot size was a major factor in the sad death of my first grafted avocado tree (we always remember the firsts the best!).
3. Temperature: For northern gardeners, this is incredibly important!!! Even an indoor-grown tree is susceptible to cold temperatures if grown too close to an inefficient window or in a room with poor heating. Indoor growth is already stressful for a tropical or subtropical native tree that is used to bright, sunny days – don’t compound the stress by adding in chilly temperatures.

A combination of these three factors is the most common cause of death for my avocado trees. For a heat-loving tree, cold, wet roots seem to rot out the tree from the inside out – and any one of the causes above (drainage, pot size, and temperature) is enough to start that rotting process. A combination of all three is almost impossible to survive.

Looking for more information on how to grow avocados in containers? Logees has a nice little article on growing avocados, and Stark Bro’s recently jumped into the avocado business as well (check out the Stark Bros avocado growing guide). As container gardening grows in popularity, different gardening resources and nurseries have started to add guides as well, so do your research before you buy – and learn from someone else’s failures instead of your own!

Not ready to start growing avocado trees on your windowsill, but still interested in experimenting with container gardening? Check out this list of 30 subtropical fruits and spices that can be grown indoors in pots!