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Gtech ST20 Cordless Grass Trimmer Review

Clever new easy-fit blades make the Gtech ST20 a simpler cordless strimmer, but can it provide the cutting power required?


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The Gtech ST20 is a fresh take on battery-powered strimmers with unique 'easy-fit' blades instead of a conventional strimmer cord. It is slightly hampered by a slow charge time, but if you can overlook that, this powerful little gem can do almost anything.


  • Strong and light
  • Fully adjustable cutting head
  • Easy to use in tight areas


  • 4-hour battery recharge time
  • Cost of the blades

Key Specifications

  • 230mm cutting diameter
  • Delivers up to 9000rpm
  • Uses replaceable easy–fit plastic blades
  • 18 volt Lithium-ion battery
  • Adjustable handle for comfort of use
  • Weight with battery 1.75kg
  • Head can be turned through 180 degrees
  • 30-minute battery life
  • 4-hour charging period
  • 96 decibels

What is the Gtech ST20 Cordless Grass Trimmer?

Part of the Gtech cordless garden tools range launched in 2016, the ST20 is designed to be comfortable and easy to use. It has an adjustable handle so it can be perfectly balanced, a one-handed power trigger, and a safety switch to prevent accidental starting. The cutting head easily converts to a precision lawn-edger, and its Lithium-ion battery gives 30 minutes of run-time with each four-hour charge. (Gtech suggests that if you want more run-time you buy an extra battery for £39.99; the same batteries can also be used in their HT20 HedgeTrimmer.) The Gtech ST20 uses easy-fit blades instead of a strimmer cord.

Gtech ST20 Cordless Grass Trimmer-design and features

The Gtech ST20 arrived needing to be clipped together. No tools were required. I simply clipped on the cutter head guard, inserted the shaft into the cutter head body, attached a replaceable plastic blade, inserted the battery, and it was ready to go. It is compact, slim and lightweight.

The Gtech ST20 is not adjustable for length. Because it is so light it doesn’t need to be adjusted for weight for different users. The second handle is fixed, but the ST20 can be adjusted for different heights of user by altering the angle of the cutting head, which is adjustable through more than 90 degrees using the large green button. You could adjust it this way for anyone from three feet to seven feet high. A small person would use it with the shaft nearly horizontal to the ground, and a tall person with the shaft at nearly 90 degrees. When it was nearly vertical it was almost too high for me, at 6ft 5in, to use.

Gtech ST20 strimmer head

There is an identical green button for adjusting the second handgrip. You simply press the button and adjust it through 180 degrees: from lying parallel to the shaft and facing the cutting head, to lying parallel to the shaft and facing the battery. This means you can alter the machine for any position or any height of user.

Gtech Strimmer controls

If you are cutting on the ground, for instance, it would feel more natural to have the handle back towards you, but if you were cutting on a bank the work would be easier and more comfortable if the handle was facing forward. This adaptability gives you much greater control across a wide range of different tasks.

Gtech Grass Trimmer handle forwardDifferent brands of white AirPods in their cases standing on a white background

The cutting head on the Gtech ST20 can be rotated 180 degrees by twisting it. You don’t have to press a button, you just rotate it. This means that you can cut in any position, from over your head to under your feet. It would, for example, be easy to trim hanging baskets or widow boxes.

There is a green safety button on the side of the main hand-grip. You push this left or right, so the Gtech ST20 can suit left- or right-handed users, and then press the trigger under the handle. The Gtech ST20 is not variable speed; it has one speed only.

You don’t use a strimmer cord in the Gtech ST20, just a single replaceable easy-fit plastic blade, which is easily fixed in place in seconds even while wearing thick gloves. The blade has a keyhole in it. You place the large hole over a button on the cutter head and then pull to snap it in place. (Twenty are supplied with the machine. A replacement pack of 20 costs £5.99 online. They cost £2.99 if you go for the ‘Blades for Life’ deal on the Gtech website , paying only for postage and packaging each time you want a new set of 20 blades. There are also cheaper generic blades available.)

Related: Best grass trimmer

Gtech Grass Trimmer in use

Gtech ST20 Cordless Grass Trimmer – charging and run-time

The Gtech ST20 has a very small battery. It weighs only 400 grams, but still has a life of half an hour. You simply slide it into position on the end of the handle.

The battery charger is simply a plug and a wire – like a mobile phone charger. The Gtech ST20 battery takes up to four and a half hours to recharge. There are four green lights radiating round the test button on the battery, and they show you how much charge you have. When all four are lit, then the Gtech ST20 is fully charged.

Gtech Strimmer battery pack

Related: Best cordless lawn mower

Gtech ST20 Cordless Grass Trimmer – Handling and performance

When I first took the Gtech ST20 out of its box I was slightly dismayed because it felt a bit plastic and fragile, but as I began to use it I realised it was actually a really good bit of kit. You can jiggle some strimmers and feel give in the handle but the ST20 felt nice and solid. It is for domestic use only, grass and light weeds, but I couldn’t help thinking that its mix of lightness, strength and adaptability might make it useful for professional gardeners, too.

The rotating head means you can go from horizontal to vertical cutting in a second. If you are cutting the top and sides of a bank it’s simply a quick flip. You don’t even have to alter your hand position.

The ST20 is so light that it is easy to strim round narrow flowerbeds, or work up on a bank where a heavy machine would be a strain. You can even use it one-handed to reach over a bush or a fence.

Gtech Strimmer in use

The easy-fit plastic blades were surprisingly great to work with. They were simple to replace, and the whole process was far quicker than replacing strimmer cord. They would be ideal for anyone with restricted movement in their hands because strimmer cord is always slightly fiddly to replace, and as long as you can squeeze your finger and thumb together the blades would be no problem to fit. I found, also, that it was immediately obvious when they had snapped because the machine vibrated more. They sawed through nettles, brambles and twigs and were definitely better at cutting than standard strimmer cord. When I really challenged them I discovered that they would take about a second to chew through a bramble thicker than a pencil. If you make them tackle individual weeds they are brilliant, but the machine will die if you force it to tackle a big clump of woody weeds or light brambles. Overall the cutting power was impressive in such a light machine. It strimmed a square metre in less than 15 seconds.

Comparing strimmer cord with easy-fit blades, I found strimmer cord was more likely to break when used to cut brambles. (The easy-fit blades coped with brambles quite easily.) Easy-fit blades were far more likely to snap off if you accidentally went up against a concrete or stone edge with them. (Strimmer cord just bounced unharmed off hard surfaces like this.) The easy-fit blades generally only started to break when they hit stones or thick twigs.

Gtech Strimmer head

The battery lasted a good 30 minutes. The only downside was that it took unusually long to recharge: four hours.

I could feel a bit of vibration when the ST20 was not cutting and was running without load, but that quickly reduced when I began to strim. It was only a minor problem because, of course, you are unlikely to run it for long without cutting.

Why buy the Gtech ST20 Cordless Grass Trimmer?

It is light, easy to use, the easy-fit blades are simple to change, it is extremely strong and adaptable, and it delivers a professional finish. I really enjoyed using it, and if the battery recharge time was shorter I’d give it five stars.


It’s a damn good little tool. The Gtech ST20 is surprisingly powerful and adaptable for the money. It can do almost anything and is ideal for small gardens or people looking for their first strimmer.

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