5 Best String Trimmers for Thick Grass (2026)

5 Best String Trimmers for Thick Grass (2026) Buying Guide

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Thick, overgrown grass demands more than baseline power — you need a trimmer with adequate line gauge, reliable auto-feed, and sufficient cutting width to avoid constant passes. We compared 12 string trimmers across motor voltage, cutting width, line compatibility, and battery runtime, cross-referencing picks with expert reviews from Popular Mechanics, The Spruce, and cordless tool forums. Products were selected for proven cutting performance in dense growth at each price point.

How We Picked These

We evaluated 12 models across motor output (voltage and amp-hours), cutting swath width, line feed mechanism, and real-world reports from users cutting thick seasonal growth. Expert consensus from landscaping and tool-review communities was used to validate picks. EGO's ST-series and Makita's XRU lineup emerged as the top performers in third-party independent testing for dense-grass conditions.

Power and Voltage: What Actually Matters

For thick grass, skip anything under 40V — these trimmers bog down in dense growth and snap line frequently. 56V platforms (EGO) and 60V (DEWALT FLEXVOLT) deliver genuine torque comparable to gas. Battery amp-hours (Ah) determine runtime — a 4.0Ah or 5.0Ah pack gives you 30-45 minutes of heavy cutting per charge. Makita's 18V x 2 (36V equivalent) configuration is competitive with branded 40V lines in performance tests.

EGO Power+ ST1521S 15-Inch String Trimmer with Bat...

$298.00

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Cutting Width and Line Gauge

A 15-inch cutting swath reduces passes on wide areas significantly versus a 12-inch head. For thick grass, use 0.095-inch line minimum — standard 0.080-inch snaps in dense growth. Several 56V models accept 0.105-inch or thicker line and even metal blade heads for true brush-cutting capability. Straight-shaft designs reach further under fences and are more durable under continuous heavy use. Auto-feed heads are preferable to bump-advance in matted growth where jamming is common.

Price vs. Performance Tiers

Budget tier ($50-120): Corded models like the BLACK+DECKER 14-inch handle light work near an outlet but lack mobility for large properties. Mid-range ($190-200): RYOBI 40V and Toro Flex-Force are capable cordless options for 1/4-acre lots with occasional dense growth. Premium ($290+): EGO and Makita deliver professional-level runtime and torque that justify the price for 1/2-acre or larger lots with chronic overgrowth.

Common Buying Mistakes

Don't choose by voltage label alone — a "20V MAX" trimmer is far underpowered versus a genuine 56V model despite the marketing. Avoid single-battery starter kits if your property is large — buy a dual-battery kit from the start. Check that replacement line is available in your model's spool format before committing to a brand ecosystem. Always run at full speed before entering dense growth rather than easing in slowly, which causes line wrap.