My current garden is only about two and a half years young. We inherited it from the previous owners in a serious state of neglect; overgrown with weeds (ugh, bind weed!), diseased and unpruned trees, and overgrown, wild beds with dead, compacted soil. It was a mess but it was full of potential. It could only get better!
When we moved in, I was pregnant with a toddler, so I began in earnest. I have completed most of the work since last spring. I know it's going to take years before it evolves into the microfarm/potager that I envision. I need some flexibility as my garden takes shape so I have put in extra effort into making the most of raised beds and container gardening. Our raised beds are constructed such that they can be lifted and moved when emptied of soil. I also have over two dozen large upcycled nursery pots in which I grow everything from arugula to apple trees. These pots generally range in size from 5 to 25 gallons, though I have two HUGE ones (3'Hx5'W) that were used to grow bamboo.
I use the 20 to 25 gallon pots for growing fruit trees. The size of these pots are large enough that they have enough room to develop a strong root system but not too large so that the trees put more energy into developing roots and foliage rather than fruit. Some degree of constriction is helpful in encouraging the trees to set fruit. They are all planted in a soil that is tailored to tree growth; the consistency is similar to garden bed soil mixed with bark mulch. You can likely buy a shrub and tree mix at a nursery.
This is a temporary solution. It allows me to grow productive fruit trees and grow them to a size that will allow me to expand my mini (i.e. seven tree) in-ground orchard in the future. Given the size of the pots and the growth rate of the trees, this should give me about three years before they'll need to go into the ground. I anticipate that my garden will have changed a great deal up to that point. Right now, I can move them around the garden to protect them from the elements and to chase the sun. I can find their 'sweet spot' before I ultimately put them in the ground. If I let them outgrow their pots, I risk needing to replace the trees, so I'll have to keep my eye on them.
I currently have two mature fruit trees (unidentified cherry and asian pear) in my garden which were severely neglected when we moved in. They are in a state where not even a pruning 'rehabilitation' will rescue them and they are showing signs of distress and disease. If (or, likely, when) they come out, I'll be able to replace them quickly with other sizable fruit trees.
You might be wondering what trees am I currently growing in containers. Like any other specimen in the garden, I chose varieties that I enjoy and are suited for my climate. I also selected them for their root stock, where applicable. The root stock is the root system to which the tree is grafted and this determines it's ultimate size. Here's what I have growing:
So, why plant trees in containers?