Husqvarna 300-3T Multi Grass Blade 578444501

What It Is

The Husqvarna 300-3T Multi Grass Blade (578444501) is a three-prong, mulching and bagging blade designed for zero-turn and riding mowers. It’s built for fine grass clipping processing and is not intended for heavy-duty or rough terrain cutting.

Fitment & Compatibility

Before buying, verify these three things:

• Deck size: Fits 48-inch, 54-inch, and 60-inch cutting decks. Measure your deck width to confirm.
• Model series: Compatible with Husqvarna MZ, Z, and R series zero-turn mowers (e.g., MZ48, Z254, R322T). Also fits some Poulan Pro, Jonsered, and Craftsman models with the same spindle pattern.
• OEM part number: This is Husqvarna OEM part 578444501. Cross-reference with your mower’s manual—aftermarket versions may differ in thickness or balance.
• Measurements: Blade length is 21 inches (center hole to tip), with a 7/8-inch center hole and a 0.25-inch thickness. Ensure your spindle matches.

Key Things to Know

• Quality: OEM blade from Husqvarna, heat-treated and hardened. Holds edge well for residential use, but dulls faster on sandy or dry grass.
• Installation: Easy swap—use a torque wrench set to 45-60 ft-lbs. The three prongs can be tricky to align; mark orientation before removal.
• Common gotchas: This is not a lift blade—poor for side-discharge. Also, avoid over-tightening, as the blade is thinner than some alternatives and can warp.
• Mulching performance: Best with dry, short grass. Wet or tall grass clogs the deck quickly.

Should You Buy It

Buy this if you own a Husqvarna zero-turn with a 48-60 inch deck and primarily mulch or bag on manicured lawns. Skip it for rough cutting, side-discharge use, or if you need a heavier-duty blade for tall, wet grass.