Short answer: wash it, dry it completely, fold it loosely into something that breathes, and keep it inside the heated part of the house. Four rules, and the failures all come from breaking one of them.
Clean, even when it looks clean
Body oils are invisible when bedding goes away and yellow when it comes back. They oxidise slowly in storage, which is why marks appear along fold lines on sets that were put away looking perfect. One normal cold wash before storing prevents the whole category of problem, and it is also the only chance to catch damage while there is still time to fix it. The washing guide covers doing it without stressing the print.
Dry means dry in the middle
The most expensive storage mistake is packing something that feels dry on the surface. Quilted sets hold moisture in the batting long after the outer fabric is dry, and a sealed month with any moisture left is how a set acquires the smell that never fully leaves. Dry on low until done, then leave it over a rail or across a spare bed for another day. Check the centre of a fold rather than the corner — the corner dries first and tells you nothing.
Breathable beats airtight, always
Vacuum bags are the intuitive answer and the wrong one for anything quilted. Compressing batting for months crushes the loft that makes a quilt a quilt, and the seal traps whatever moisture survived. Cotton storage bags, pillowcases, or lidded fabric cubes all work. A rigid plastic bin is fine in a dry climate if the lid is not clamped down and the contents went in bone dry. Cardboard is the worst option: it attracts insects and wicks damp from whatever it stands on.
Inside the insulation, not the attic
Attics swing from freezing to oven temperature and back, which ages fabric faster than use does. Garages add damp and exhaust to the same cycle. Basements add humidity. The rule that covers all of it: store bedding somewhere you would be comfortable sleeping. A wardrobe top, a closet shelf, under a bed — all fine. Away from direct sunlight, which fades a folded edge in stripes, and away from the water heater.
Fold loose, stack light
Tight folds become permanent creases and weight makes them permanent faster. Fold in thirds rather than quarters, put the two shams inside the folded quilt so the set stays together and the folds get padded, and do not stack anything heavy on top. Flat under a bed is the ideal if the space exists, because it involves the fewest folds and no compression at all.
Label, because next year you will not remember
A strip of masking tape saying what is in the bag, what size it is, and when it was washed answers next season's three questions before they are asked. Households running a seasonal rotation get the most from this — it is what stops the Christmas set and the year-round set trading places by accident in a spring reshuffle, which is a small annoyance that happens far more often than it should.
Pests, and the cedar question
Moths eat protein fibres — wool, silk — not cotton, so a cotton-covered quilted set is a low-risk item. What draws them is residue: skin, food, sweat on a set stored unwashed. Clean storage is therefore the whole defence, and cedar or lavender are pleasant rather than necessary. Silverfish are the other household concern and they are attracted to damp and to cardboard, which is one more reason for a fabric bag on a dry shelf rather than a box on a basement floor.
Coming out of storage
Ten minutes in the dryer on low, or an hour spread on the bed in a warm room, and folds relax on their own. If a cupboard smell has developed despite everything, one rinse cycle with a half cup of white vinegar resets it and leaves nothing behind once dry. Bedding stored properly should need no more than this — if a set needs a full wash the moment it comes out, the storage was the problem, not the set.
Where households actually go wrong
Three mistakes account for nearly all ruined stored bedding, and none of them are exotic. Storing a set that was clean-looking but unwashed, which produces yellow fold lines a year later. Packing it the same day it came out of the dryer, when the batting was still holding moisture. And putting it in the attic because that is where seasonal things go — the one place in the house with the widest temperature swing. Avoiding those three does more than any storage product sold for the purpose.
How long can bedding stay stored?
Indefinitely, if the four rules were followed — cotton stored clean, dry and dark is stable for decades, which is why hundred-year-old quilts exist in good condition. What actually limits it is the storage environment rather than time: humidity, light and pests. A set going away for more than a year is worth checking once at the six-month mark, mostly to confirm the container and the location were right. If it smells fine and feels dry at that point, it will keep.
The seasonal version
Everything above applies year-round; seasonal sets have one extra consideration, which is timing. Wash and store the moment the season ends rather than when the next one starts, because a set left out through spring collects dust it never gets credit for. The Christmas storage guide covers the specific case, and the seasonal calendar maps when each set should be going away.