Last updated: 2 October 2026
Why a strip is left at the edge
On most robotic mowers the blade disc sits in the middle under the housing. The mower drives up to the boundary wire or the edge, but the blades only reach the area under the housing. The smaller the disc compared with the housing, the wider the strip you have to trim by hand.
For comparison: on the Gardena Sileno City we measured the original disc at approx. 14.5 cm, with a cutting width of approx. 16 cm.
What helps
- Check the boundary wire: lay it as close to the edge as your manufacturer's instructions allow. Many strips exist because the distance is larger than necessary.
- Add a mowing edge: a flush stone or metal edge the mower can drive on lets it get closer to beds.
- Use the edge function: some models can drive along the edge on purpose. Your manual tells you whether yours can.
- Use a larger blade disc: a larger disc increases the cutting width. Our 21 cm tuning blade disc cuts approx. 24 cm wide, clearly more than the original disc.
What to look out for with a larger disc
- The disc has to fit the motor mount (round with 22 mm hole spacing, or hexagonal). The quickest way to check is the compatibility check.
- After fitting, the disc must run freely everywhere at the set cutting height. See the installation guide.
- Blunt blades tear the grass rather than cut it. Change them regularly, see changing blades.