How Does Stump Grinding Work?

Home › Advice Centre › Stump Grinding

A stump grinder is a purpose-built machine with a heavy steel wheel on the front, set around its rim with tungsten carbide teeth. The wheel spins fast and is swept side to side across the stump, taking off a layer at a time.

It does not pull the stump out. It reduces it in place to chippings.

A stump grinder cutting into a tree stump.

The Sequence on Site

The stump is cut down low if it is not already. Less height above ground means less to grind and a quicker job
The ground around it is checked and cleared. Stones are the main enemy — a tooth meeting a buried rock chips the tooth and throws the stone. Old paving, hardcore and rubble around a stump all matter
Services are established. This is the part that is not optional. Water, gas, electricity, telecoms and drains all run through gardens, and a grinder will go straight through any of them
Boards and screens go up where there is glass, a car, a fence or a pond within range. Grinding throws material further than people expect
The stump is ground, working across and down in passes
The hole is dealt with as agreed — grindings back in, levelled, or taken away and topsoil brought in

Buried services are the real risk in stump grinding, not the stump. If you know where anything runs — a water pipe to an outside tap, an armoured cable to a shed or a garden light, a soakaway — say so before the work starts. A stump two metres from the house is often close to a drain run.

What Is Left Behind

A hole roughly the size of the stump, filled with a loose pile of wood chippings and soil mixed together. The volume of grindings is always more than the stump appeared to be, because chipped wood occupies far more space than solid wood.

The chippings can be left in the hole and topped with soil, spread elsewhere as a mulch, or taken away. What you want to do afterwards decides which.

The Machines, and Why Size Matters

Narrow-access machines are built to go through a standard side gate, roughly 70 to 80 centimetres. They are slower on a large stump but they can get into an ordinary back garden
Larger tracked machines work much faster and go deeper, but need genuine access — a wide gate, a driveway, or open ground

This is why we ask for the gate width rather than just the stump size. The stump determines how long it takes; the gate determines whether it can be done at all.

What Grinding Does Not Do

It removes the stump and the root flare immediately around it. It does not remove the root system, which stays in the ground and decays over several years. For most purposes that is fine, and the separate article on what happens to the roots covers when it is not.

View our Hertfordshire Stump Grinding service →