David Hare-Scott wrote:

Jonno wrote:
44 half drum OK . Full drum too heavy and too deep.(thoroughly
cleaned), Soil, suggest :Add a good grade potting mix with added cow
manure and well mulched.

Ten tubs will take many bags, which will take much mixing and be
expensive. I would get good loamy soil delivered in bulk if possible.
Do the sums, half a 44gal drum is about 100l.

A few drain holes and pebbles in the bottom for drainage.Raised of
the ground.
And yess, make sure theyre well shaded in hot weather and well
watered, but not with wet feet...

Agreed, tubs, even big ones, dry out much faster than the ground. You
may need to water daily in extreme heat. And mulch their tops. And
cluster them together to get mutual shading of tubs.

If large commercial self-watering pots are out of budget , two things. I
believe you can buy a kit to retrofit an existing pot (but I suspect they
are probably out of budget as well).

Secondly, you could make your own self watering pot from a recycled
container. It just requires a hole in the side to let excess water out,
say a few inches from the bottom, then a supported water-resistant mesh of
some sort to keep the soil out of the water. You could also add a piece of
19mm ag pipe from the top for watering (or just let it trickle down). The
plant will put the odd root into the water but not enough to get wet feet
and die.