Hi Mrs Jones,
I have an apple tree grown in an old water butt, in the garden. It’s around 10 years old and does really well
I have a lemon tree which lives in the greenhouse all year round, in its own large terracotta pot; I can’t remember what the litre size is, but it must be at least 80 litres.
I planted a bare root plum tree this year, into another old water butt, which seems to have settled well.
I grow all of my fruit and veg in pots or gro-bags. Nothing goes into the ground. It j7st makes it easier for me to keep things under control and not bother too much with weeding.
I’ll have some raised beds from next year, so I’ll see how much better things grow in those. My other half is making those for me and is building brick ones, open to the soil at the bases.
I’d say you probably need at least 80 litre containers, but it depends on the varieties you choose and how big you want them to grow.