How to Store a Lawn Mower: Short-Term and Long-Term Storage Guide

How to Store a Lawn Mower: Short-Term and Long-Term Storage Guide

Storing a lawn mower correctly protects the engine, prevents corrosion, and ensures reliable starting after any storage period — whether it’s 2 weeks or 6 months. The key difference between short-term and long-term storage is fuel management: short pauses don’t require fuel treatment, but anything over 30 days does. This guide covers both scenarios so you can store your mower correctly for the situation. For a broader overview, see our essential lawn mower guide.

What You’ll Need

• Fuel stabilizer (for storage over 30 days)
• Light machine oil or WD-40 (for metal surface protection)
• Breathable mower cover (optional)
• Battery tender/trickle charger (for riding mowers)
• Work gloves

Safety Precautions

• Never store a running or warm mower — allow the engine to cool completely before covering or storing in an enclosed space.
• Never store a gasoline-powered mower indoors where combustion appliances (furnaces, water heaters) have pilot lights — gasoline vapors are flammable.
• Store fuel in approved containers, away from heat sources and direct sunlight.

Short-Term Storage (Under 30 Days)

For periods under 30 days between mowing sessions, standard cleanup is sufficient:

• Clean grass clippings from the deck top and underside — packed wet clippings cause rust.
• Wipe down the engine housing.
• Store in a dry, covered location — garage or shed is ideal. Avoid storage directly on concrete if possible — concrete wicks moisture. Place the mower on a mat or pallet.
• Leave fuel in the tank — it won’t degrade significantly in under 30 days.

The most common short-term storage mistake is leaving wet grass packed under the deck. Even over 2 weeks, packed wet grass generates enough moisture to cause surface rust on the deck underside and accelerate corrosion at blade attachment points.

Long-Term Storage (Over 30 Days)

Long-term storage requires fuel treatment in addition to regular cleaning. Ethanol-blended fuel (E10 — the standard gasoline at most stations) begins degrading within 30 days, leaving varnish deposits in the carburetor that cause spring no-starts.

Option A: Add Fuel Stabilizer

1. Fill the tank with fresh fuel (to minimize airspace where condensation forms).
2. Add fuel stabilizer at the label’s recommended ratio.
3. Run the engine for 5–10 minutes to circulate stabilized fuel through the carburetor.
4. Shut off the engine and proceed with other storage steps.

Option B: Empty the Fuel System

1. Run the mower until fuel is exhausted, OR siphon fuel into an approved container.
2. Start the engine and run until it stalls from fuel starvation — this empties the carburetor float bowl.

For complete winterization steps (oil change, spark plug, air filter), see our full lawn mower winterization guide. The storage guide here focuses on location and covering — the winterization guide covers mechanical prep.

Best Storage Locations

Should You Use a Lawn Mower Cover?

A cover is helpful in certain situations but counterproductive in others:

• Use a cover when: Storing outdoors or in an uninsulated shed where temperature swings cause condensation on metal surfaces. A breathable cover (fabric rather than plastic tarp) protects from dust and debris without trapping moisture.
• Skip the cover when: Storing in a dry, climate-controlled garage. A cover in a dry environment is unnecessary and slightly reduces airflow around the mower.
• Never use a plastic tarp directly on the mower: Plastic traps moisture against metal surfaces, accelerating rust — the opposite of protection. Always use a breathable fabric cover or leave the mower uncovered in a dry space.

Riding Mower Storage

Riding mowers require the same fuel and mechanical prep as walk-behind mowers, plus additional attention to the battery and tires:

• Battery: Connect a battery tender set to maintenance mode. A 12V lead-acid battery left uncharged over winter discharges completely and often can’t be recovered. See our riding mower battery guide for battery maintenance details.
• Tires: Check and equalize tire pressure before storage. If storing for more than 6 months, consider propping the mower on blocks to prevent flat-spotting from prolonged contact with concrete.
• Deck: Clean all grass from the deck underside before storage — wet grass left over winter accelerates rust on the deck shell. See our lawn mower deck cleaning guide for detailed deck cleaning steps.
• Hydrostatic fluid: Check fluid level and top off per manufacturer spec before long-term storage. Cold temperatures increase fluid viscosity, and starting the season with low or degraded fluid stresses the transmission on first use.

Battery-Powered Lawn Mower Storage

Lithium-ion batteries (used in battery-powered mowers) have specific storage requirements that differ from gas mower batteries:

• Store batteries at 40–60% charge — not fully charged and not fully depleted. Lithium-ion cells degrade faster at 100% charge during long storage.
• Store in a temperature-controlled location, ideally 40°F–77°F (4°C–25°C). Extreme cold permanently reduces capacity; extreme heat accelerates cell degradation.
• Do not store batteries in an unheated garage that goes below freezing — bring them indoors.
• Check battery charge every 3 months during storage and top up to 40–60% if needed.

For a complete guide on cordless mower battery performance and maintenance, see our cordless lawn mower battery life guide.

Frequently Asked Questions

Can I store a lawn mower vertically to save space?

Some lawn mowers are specifically designed for vertical storage — check your manual first. If your model supports it, tip it with the air filter and carburetor side UP to prevent oil from flowing into these components. Never tip with the carburetor side down.

How long can I leave fuel in the tank without treatment?

Untreated ethanol-blended fuel (E10 standard gasoline) should not sit longer than 30 days. After 30 days, fuel begins to oxidize and phase-separate. Ethanol-free fuel lasts 60–90 days without treatment. After 90 days, even stabilized regular fuel should be replaced.

Can I store a lawn mower in my basement?

No. Gasoline vapors are heavier than air and accumulate at floor level. In a basement, these vapors can reach a furnace, water heater pilot light, or other ignition source. Even a “dry” tank retains enough fuel vapor to create a fire risk. Store gas-powered equipment only in detached garages or outdoor sheds.

Do I need to remove the blade before storage?

Not required, but end-of-season is a good time to inspect and sharpen or replace the blade. See our lawn mower blade guide for inspection criteria. A sharp blade at the start of the season means better first cut quality.

How do I prevent mice from nesting in my stored mower?

Mice commonly nest in mower engines over winter — in the air filter housing, under the fuel cap, and inside the engine shroud. Placing steel wool in the air intake opening (remove before starting) and using repellent pouches near the storage area reduces nesting. Check the engine compartment before spring startup and remove any nesting material before running.

Conclusion

Proper lawn mower storage comes down to three priorities: treat the fuel for any storage over 30 days, store in a dry covered location (never under a plastic tarp outdoors), and maintain the battery for riding mowers and battery-powered equipment. These three steps eliminate the most common storage-related failures and ensure your mower starts reliably when mowing season returns.

Related storage and maintenance guides:

• How to Winterize a Lawn Mower
• Lawn Mower Maintenance Schedule
• Lawn Mower Deck Cleaning Guide
• Riding Mower Battery Replacement
• Lawn Mower Fuel Type Guide