How to use a post hole digger
Updated: October 2026
You have a narrow spade in one hand and a clamshell in the other, or you have only one of them and a fence post waiting. The usual mistake is to drive the post-hole digger into hard ground as if it were a bar, or to take the first thrust before anyone has asked what is under the turf. This is how to use a post hole digger: locate services, cut and loosen with the blade or a bar, then lift with the clamshell. The tools are on the [hole spade comparison](/hub/digging-tools/hole-spade). Peter F. compared the listings and public UK sources in October 2026. There was no lab test. A qualifying purchase can earn a commission at no extra cost to you.
You have a narrow spade in one hand and a clamshell in the other, or you have only one of them and a fence post waiting.
You have a narrow spade in one hand and a clamshell in the other, or you have only one of them and a fence post waiting. The usual mistake is to drive the post-hole digger into hard ground as if it were a bar, or to take the first thrust before anyone has asked what is under the turf. This is how to use a post hole digger: locate services, cut and loosen with the blade or a bar, then lift with the clamshell. The tools are on the hole spade comparison. Peter F. compared the listings and public UK sources in October 2026. There was no lab test. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Job | Weight | Shaft | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Spear & Jackson Spear & Jackson 2154HK draining shovel | Cuts the slot | 2.79 kg | Tubular steel, 711 mm | 9.4 | about £16.20 | View offer |
 Roughneck Roughneck drainage and post hole shovel | Cuts the slot | 1.98 kg | Fibreglass, 1070 mm | 9.4 | about £21.54 | View offer | |
 Roughneck Roughneck ROU68250 post hole digger | Lifts loose spoil | 5.2 kg | Fibreglass, 1500 mm | 9.4 | about £39.99 | View offer |
On this page
Before you break the ground
The Health and Safety Executive’s excavations guidance is written for people who dig for a living, and the principle still applies in a garden. Look at plans. Use a locator if the route is unclear. In Great Britain the Energy Networks Association’s line is 105. On a street, a shared drive, or a house that has been extended more than once, assume you do not know the route until you have checked. Conservation-handbook fencing practice says the same for urban sites: check services before you dig.
HSE construction sheet CIS65 says you should not use a power tool or a mechanical excavator within 0.5 m of a suspected cable route. A hand spade is not a free pass inside that distance. If a cable is suspected, insulated tools and a careful dig from the side are the safer description, and an ordinary drain shovel is not an insulated tool. That is often the moment to hand the hole over. Do not wet the ground to soften it beside a service you have not ruled out.
Cut, then lift
In difficult ground the conservation handbooks and the Inland Waterways hand-tool note agree. A bar, a Newcastle draining tool or a trenching spade breaks the hole. The clamshell removes spoil. It is not there to dig, except in very soft soil, sand or peat. If you only own the clamshell, get a blade before you attack dry clay. Reviews of the Spear & Jackson PHD-WH and the Roughneck 68-250 say the lifter works once something else has loosened the soil, and it is poor at cutting unbroken ground.
Set the drain spade on the mark, drive it with your boot if it has a tread, and take small bites. Work around a circle a little larger than the post, not a square you will have to fill. Empty the slot while the blade still reaches. When the hole is deeper than the blade can clean, that is the clamshell’s job. Close the handles and drive the blades into loosened soil. Spread the handles to bite, bring them together to grip, and lift straight up. Dump to the side, not back into the hole. Keep the width you marked. Depth for a garden fence sits on the hole spade for fence posts page. Why the pair exists is on the drain spade versus post-hole digger page. If the jaws start to bend, or a screw-together digger unscrews in the hole, stop using it as a breaker.
Stones, roots and dry spoil
A stone needs a bar, not a harder swing on fibreglass handles. Reviewers of the Roughneck 68-250 still want a bar or a drainage shovel for rocks and hard clay. The Neilsen CT1148 twists or warps on stones and small roots, or if you rotate it like an auger. Rotation ruins a clamshell. Pull it out, break the obstruction, then lift the crumbs.
Dry or sandy soil will not stay in the jaws. PHD-WH reviews say dry spoil falls back into the hole. Take smaller lifts, and pare the sides with the narrow spade. Do not soak the hole. If you hit a cable, a pipe, or water you cannot explain, get out and do not keep hold of a tool that may be live. Call 105 for the electricity network in Great Britain. A tool that has started to bend is finished for the day. One 2154HK review describes a bend, and the OLLIDOT sample includes bending or breaking on early holes.
Body and boots
Garden Organic’s digging notes are written for beds, and the posture still applies. Keep your back upright, bend your knees, and work in short spells. A 5.2 kg clamshell plus soil is a shoulder exercise if you rush a long run. Wear stout boots. Steel toecaps are the sensible version when you are driving a forged head. The waterways note asks for stout boots around these tools. Check that knuckle guards line up. Pain in your lower back is the signal to stop for the day.
When you stop and get help
A professional, or a hire auger and someone used to it, takes over when you suspect a service, when unexplained water appears, when the ground is a long compacted run, or when the tool starts to bend. A short garden run in soil you have loosened is still a hand job. A trench towards a known cable route is not the moment to learn the clamshell. Call 105 for an electricity emergency in Great Britain and do not keep hold of a tool that may be live.
Common questions
What do I do before the first thrust?
Check for buried services. Look at plans, use a locator where the route is uncertain, and in Great Britain you can reach the electricity networks on 105. Mark a narrow hole with vertical sides, then put the blade in. A drain shovel and a clamshell are both uninsulated. If you are near a suspected cable, CIS65’s warning about powered tools within 0.5 m is a reason to stop and rethink, not a reason to dig faster by hand.
Which tool breaks the ground, and which lifts it?
The narrow drain spade, grafting spade or a bar breaks the ground. The clamshell lifts spoil that is already loose. Handbooks allow the clamshell to make the hole only in very soft soil, sand or peat. In clay, using the jaws as the breaker is how they twist or bend. Switch to the lifter when the spade can no longer clean the hole easily.
How do the clamshell handles work?
Close the handles and drive the blades into loosened soil. Spread them to open the jaws, then bring them together to hold the spoil. Lift straight up and dump clear of the hole. Do not rotate the tool to drill. If the blades stop, you have hit something solid and you need the bar or the spade, not a harder pull on the hinge.
Why does dry soil fall back in?
Dry and sandy spoil will not pack inside the jaws, so it drops out on the way up. Reviews of the ash-handled Spear & Jackson post-hole digger describe that. Take smaller bites and tidy the sides with the narrow spade. Forcing a wider, wetter hole is not the fix, especially if you have not ruled out a buried service.
What if I hit a stone or a root?
Stop levering with the clamshell. Break stone with a bar, and cut roots with the spade or a saw, then lift the loose material. The Neilsen is reported to twist on stones and small roots. The heavy Roughneck clamshell still gets paired with a bar in reviews. A root the serrated shovel will not cut is a saw, not a bounce on a bolted shaft.
What boots and posture should I use?
Wear stout boots, ideally with steel toecaps, because your foot is next to a blade. Keep your back upright, use your knees, and take short spells, particularly with a clamshell listed around 4–5 kg before the soil. Check that knuckle guards line up. Pain in your lower back is the signal to stop for the day, not the signal to lean further over the hole.
When do I stop and get help?
Stop if you suspect a cable or pipe, if you strike a service or unexpected water, or if the tool starts to bend or come apart. Call 105 for an electricity emergency in Great Britain and do not keep hold of a tool that may be live. Also hire an auger, or bring in someone used to the ground, when the run is long, compacted and beyond a short garden fence. A single gate post in soil you have loosened is still yours to finish.
Related pages
Sources
Public UK sources from the research digest. Prices, stars and review counts are the amazon.co.uk listing lines used in this comparison. We did not run a lab test.
- HSE — excavation and underground services (retrieved October 2026)
- HSE HSG47 — avoiding danger from underground services (retrieved October 2026)
- HSE CIS65 — excavating near underground services (retrieved October 2026)
- Energy Networks Association — Think before you dig (retrieved October 2026)
- BSI BS 3388:2004 — forks, shovels and spades (retrieved October 2026)
- Conservation Handbooks — hole digging for a post and wire fence (retrieved October 2026)
- Jacksons Fencing — how deep to dig fence posts (retrieved October 2026)
- Consumer Rights Act 2015 (retrieved October 2026)