Over the last 10 years I’ve dug a lot of holes for a lot of plants, and after enough failures and trying out enough methods I’ve settled on one method and one tool.
And it’s not a spade or an auger. Spades are just too much work and when the ground is hard, rocky or full of tree roots they are a heck of a lot of work. Motorised augers aren’t much better unless you’re on soft loam or previously worked ground. And if you happen to get the auger snagged on a tree root you’ll end up on a downward spiral.
The other problem with the spade and the auger is that they both create a hole with smooth sides. You see, a plant’s roots don’t want to be growing in a neat hole surrounded by hard ground because it makes it difficult to grow out into the hard undisturbed ground around the hole. And in the case of a perfectly round auger hole, roots may just keep spiralling around inside the hole as if they were pot bound. This isn’t usually a problem in sandy or loose ground, but in heavy clays this can be disastrous. The second problem is that in clay the smooth holes trap water. This can result in plants being completely waterlogged during the wet season and subsequently dying. Some people give the advice that this “smooth hole” problem can be solved by stabbing at the inside of the hole with a crow bar to break up the edges and giving the root a location to penetrate the surrounding hard soil. Fair enough, but to be honest it’s a lot of effort to go to for a hole. Not only do I need a heavy noisy and smelly auger that will try to rip my arm off every time it snags on a tree root, but now I also need to carry a crow bar!
My tool of choice is a pick mattock with a nice broad blade on one side and a sharp narrow pick on the other. I use the pick to break up the ground by hitting it in as far as I can and then levering the ground up to break up the soil. Usually four hits does the job. Next I use the broad side of the mattock to create a hole in the centre of the broken ground just big enough to fit the plant into. Just remember, loose aerated soil with effective drainage is much more important to a plant than a neat hole and if done correctly you should end up with a broken area of ground about half a metre in diameter and at least 30cm deep with great drainage and lots of loose ground for the roots to spread through. Just remember, you don’t need to dig an actual hole, you just need to break up the ground.
See you at Yuruga.