AusBonsai

I'd like to add, to Ray's fantastic info, my little bit of bonus. I live on a rock ridge with lots of clay, so digging isn't easy, plus I'm an old woman...so I decided to go with a hay bale garden. Sitting the colanders on the top of the bales (after they're conditioned,) gets them growing very quickly. Digging them in a bit makes it even better, they go gangbusters. Sure, the bale does fall apart in a couple of months, but it's usually able to hold together long enough to give you a chance to root prune twice a year, Late Winter and early Autumn....depending on when you get your bales going, of course.

Straw bales are cheaper than lucerne hay, but the straw bales often have oats still in them, so you will get them sprouting alongside your colanders. I used lucerne the first time, and the mulch was so much richer....but either will do the trick.

https://modernfarmer.com/2013/07/straw-bale-gardening/