I used to stack my patio cushions in a corner of the garage and forget about them until spring. Every year at least one came back out with mildew spots or a mouse nest inside. One year I had to replace all of them, and that was not cheap.

The problem was never the cushions. It was how I stored them.

Clean first, always

Whatever you do, do not put dirty cushions into storage. Spilled sunscreen, sap, and bird droppings all set in over the winter and become impossible to remove by spring.

1. Vacuum the cushions, then spot clean any stains with mild soap and water.
2. Let them dry completely for at least a full day. Dampness in storage is what causes mildew.
3. Store them in breathable bags, not plastic, so air can move.
4. Keep them up off the floor on a shelf or a pallet.

The drying step is the one I blew off the first year, and the mildew was my reward. Dry is the whole game.

Where to keep them

A dry shed or garage shelf is ideal. If you have to store them outside, use a deck box that seals, and still put them in breathable bags inside it. Mice love cushion stuffing, so anything that blocks them from getting in is worth it.

I also started standing cushions on their side instead of stacking them flat. Stacked flat means the bottom cushion carries all the weight and gets crushed out of shape. Standing them lets them keep their shape through the winter.

Since I started doing this, the same set has lasted me four summers instead of two. That alone paid for the deck box.