Not Oil Or WD-40: The Alternative Solution That Keeps Grass From Sticking To A Mower Deck

Grass creates two problems when it sticks to the underside of a lawn mower. Firstly, it interferes with the blade rotation, making the mower work harder and shortening its life. The second is that it seals moisture against the mower deck, promoting rust, which also shortens the overall lifespan. Cleaning grass stuck to a mower is a chore no one looks forward to, and, to make it easier, people often spray the deck with WD-40 or cooking oil. That's just a temporary fix that has to be repeated often, and it's one you probably wouldn't need if you gave the deck a fresh coat of paint. 

All kinds of paint products are recommended for this, including enamel, urethane, and alkyd-based coatings, and many are available at big box stores. For example, RustSeal from KBS Coatings is a moisture-curing urethane that you can brush or spray, and although it may help repel grass to some degree, the manufacturer explicitly avoids making this claim. What it does do, besides treating rust, is make a hard, slick surface that grass is less likely to stick to, instead of one that's pitted, porous, and hard to clean grass off of. 

Majic Black Matte Non-Stick Mower Spray Paint is another product you can use, and the manufacturer of this alkyd-based paint does say that it prevents grass from sticking. It comes in an aerosol can, which makes it easy to apply, and contains graphite, which is an ingredient in many non-stick spray coatings. 

An important factor when choosing a paint product is the condition of the mower. If it's severely rusted, suppressing the rust would be a high priority, and that's a job for a product like RustSeal. On the other hand, if the mower is fairly new and in good condition, you can go for a paint that contains a non-stick additive like graphite. It may not fight existing rust, but by shedding grass and the moisture it carries, it will help prevent rust from forming in the future. 

To paint the underside of your lawn mower, start by safely removing the blade and taping over the rotor and anything else that shouldn't be painted, then follow the same procedure you'd use to paint any metal surface. Scrape and brush off loose grass, then use the scraper or a drill with a wire wheel to remove any stubborn grass and loose existing paint that's flaking off. Finally, wash the metal with a cleaner that degreases to ensure paint adherence, apply an anti-rust agent over existing rust, then let everything dry overnight. 

For some products (especially urethane and enamel paints), you may have to mix in a hardener or thinner according to instructions. Working in a well-ventilated space, apply the paint by spray or brush, and wear a respirator to protect yourself from the fumes. The paint may dry quickly to the touch but take longer to harden completely, so consult the product label for the amount of time you need to wait before mowing. Painting the undercarriage is, of course, more work than spritzing on some WD-40, but you won't have to do it as often, and it can prolong the lifespan of your mower.