By Jim McCausland, Sunset senior garden writer

By late November, the grass almost stops growing, and (unless you live in the southern tier), you can put your mower away. Just winterize it before you do, and it will work better than ever when you start it up in spring. Just do these things, all of them easy.

Run it dry. Gasoline starts degrading after it sits for about a month, oxidizing into something like varnish. That’s bad for your mower’s engine. On your last mowing of the year, run the tank dry. If you can’t do this, top off the tank and add a fuel stabilizer.

Change the oil, part 1. Start by draining out the old oil. If your mower has a drain plug next to the blade, tip the mower back, put a catch pan under it, and unscrew the drain plug. After all the oil is out, put the plug back. If there’s no drain plug, you may have a mower (like my Honda, pictured at left) in which the filler tube doubles as the drain tube. In that case, tip the mower onto its side and drain the crankcase. Don’t put oil back into the mower yet.

Hose out the deck. Grass mats into a papier-maché -like coating on the underside of the deck. Tip the mower—now empty of gas and oil—up on its side and hose it clean.

Check the blades. After even a season, blades can become unbelievably dull. After disconnecting the spark plug cap and the battery, if the mower has an electric starter, remove the bolt—or bolts—that secures the blades and sharpen them for next season, or replace them.

Change the oil, part 2. Add oil. Walk-behind mowers usually take 10 to 16 ounces of 10-30 or (in hot climates) straight 30-weight motor oil. Add until it reaches “full” on the engine's dip-stick.

Check the air filter. Most mowers have either an oiled sponge filter, or a dry fiber (like paper) filter. It’s usually covered by a plastic housing that snaps free, or comes off with the turn of a screw.
•If it’s a dry filter, tap it to dislodge seeds, grass, and other loose dry matter. If the filter looks pretty clean when you’re done, reinstall it. If it’s stained with oil or clogged, replace it.
•If it’s an oiled sponge filter, take it out and wash it in warm soapy water. If the filter is degraded or torn, replace it. If not, rinse well, squeeze it as dry as you can, and re-oil it with an ounce or two of light motor oil. To do that, put the oil and the sponge filter in a plastic baggie, and work the oil into the sponge with your fingers.

Check the spark plug. Do this if it hasn’t been changed in a few years. Take it out and look at the electrodes: they should be clean (not fouled with oil) and the porcelain uncracked. If not, replace it.

Final check. Look for all the little stuff that’s driven you crazy all season. Replace missing bolts that have vibrated loose on the push arms, replace your bag if you need to, replace the drive wheels if they’ve become so bald that they slip on damp grass. Mower dealers have all these things, they're usually relatively cheap, and you shouldn't have to live with jury-rigged repairs.