How to dig a plant hole in heavy clay soil?

[PennyC]

I need to dig multiple holes for new plants (up to 15cm pot size) in heavy clay soil. I’ve heard Landcare use a drill and a special bit to do this quickly and easily. Is this true and what bit do I buy? Thanks!

[JacobZ]

Hi @PennyC,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

For holes around 15cm in diameter, you'd want to look at something like the Ozito PXC 18V Brushless Planting And Digging Tool or Ryobi 18V ONE+ Brushless Cordless 150mm Planting And Digging Tool. They come with a 150mm auger bit and dual handles for added control as they produce a lot of torque.

For smaller holes, there are garden auger bits like this 100mm Garden Auger Bit and this 50mm Garden Auger Bit, which can be attached to a standard drill. In saying this, heavy clay would require significant torque, so you'd want to look at a higher-end drill with a secondary handle like this Ryobi 18V ONE+ HP Brushless Premium Hammer Drill. Having the secondary handle will give you more control over the tool, as they can kick pretty hard and hurt your wrist if they strike something like a rock.

If you were going even bigger, there are post-hole diggers that have even more torque and are often used with auger bits that are 300-450mm in diameter. On the higher end, they require two operators because they produce so much torque.

Let me know what you think and if you have further questions about anything mentioned, please let me know so I can assist further.

Jacob

[PennyC]

Thanks again @JacobZ ! So helpful!

I'm wondering if rather than using the drill attachment, I purchase something like this https://www.bunnings.com.au/cyclone-150mm-auger-post-hole-digger_p3360162?

the reviews seem good for this or the smaller 100mm one.

[JacobZ]

Hi @PennyC,

I can't say I've used one myself, but I have seen them used, and they worked well for a good manual solution.

They still take a bit of elbow grease, but to me, that's part of the fun of gardening.

Jacob

[PennyC]

Great. Thanks @JacobZ!

if anyone else out there has tried using something like this in clay soil, please let me know https://www.bunnings.com.au/cyclone-150mm-auger-post-hole-digger_p3360162

[AlanM52]

Hi @PennyC,

I suggest you do the combo thing with the Cyclone Post Hole Digger.

Ozito 710W Hammer Drill.

https://www.bunnings.com.au/ozito-710w-hammer-drill_p0299328

Full Boar 50mm Garden Auger Bit.

https://www.bunnings.com.au/full-boar-50mm-garden-auger-bit-fbga-50450_p0631345

I have helped people who have post hole diggers like that and it is tough going.

That combo will reduce the required effort to use the Cyclone post hole digger by two thirds.

Start with the post hole digger to mark the ground.

Bore a circular series of holes which leaves you with with one third of clay to cut through with the post hole digger.

Hope that makes sense...I actually confused myself 😃

Cheers

[MitchellMc]

Depending on the number of holes you need to create, @PennyC, it would be challenging to only use the Cyclone 150mm Auger Post Hole Digger on clay-based soil. If you have more than a few holes to dig, I recommend hiring a hole digger for the day.

Mitchell