Robot Mower vs String Trimmer — Complements, Not Replacements

MA MowAutonomous Editorial Team · Updated 2026-06-23 · 8 min read

Robot mowers and string trimmers serve different purposes. A robot mower handles the bulk of the lawn; a string trimmer handles the edges and tight spaces the mower can't reach. You need both. This guide explains how they work together.

They're Complements, Not Replacements

A robot mower and a string trimmer serve different purposes. The robot mower mows the open lawn (90-95% of your yard). The string trimmer handles edges, tight spaces, and obstacles the mower can't reach (5-10% of your yard). You need both for a fully maintained lawn.

What the Robot Mower Does

The robot mower handles: (1) Open lawn areas. (2) Slopes (if AWD). (3) Multi-zone properties. (4) Regular maintenance mowing (2-3 times per week). The robot mower eliminates 90-95% of your mowing time.

What the String Trimmer Does

The string trimmer handles: (1) Edges along fences, walls, and garden beds (the 2-4 inch strip the mower can't reach). (2) Around tree trunks and obstacles. (3) Slopes too steep for the mower. (4) Tight corners and narrow passages. Plan to string trim every 2-4 weeks during growing season.

Recommended Setup

For a typical 1/4-acre lawn: (1) Robot mower ($1,500-$3,000) — handles 95% of mowing. (2) Battery string trimmer ($150-$300) — handles edges and tight spaces. (3) Total cost: $1,650-$3,300. Total weekly time: 30-60 minutes for string trimming (vs. 2-3 hours for push mowing).