The short answer
Yes, a garage is fine for plastic foliage, light strands, tinsel and outdoor decorations, in sealed rigid containers kept off the floor. Glass, painted pieces, paper, and anything with real pine cones or berries belong inside the conditioned part of the house. That split costs nothing and matters more than any container you buy.
The three locations, honestly
What each location does over ten months | Attic | Garage | Basement |
|---|
| Temperature swing | Largest | Large | Smallest |
| Humidity | Usually lowest | Variable | Usually highest |
| Pest access | High | High | Moderate |
| Light exposure | Usually none | Often some | Usually none |
| Access | Worst, via a ladder | Best | Good |
| Best for | Paper, fabric, tinsel, artificial foliage | Outdoor decor, lights, tree, bulk | Glass, painted, ceramic, if dry |
| Worst for | Glass, painted, glued | Anything organic or paper | Anything absorbent, if damp |
Temperature swing is the real mechanism
People think about heat and cold, and the thing that actually causes damage is the cycle between them. Materials expand and contract at different rates: glass against a metal cap, paint against ceramic, glue against wood. Every cycle works those joints slightly.
An unconditioned attic cycles hardest, because it is directly under a roof and follows the outside air with amplification. That is why old glass ornaments, painted pieces and anything glued do worst there, even though nothing in an attic is at an extreme for long.
A basement cycles least, which is why it is generally the better of the two for delicate things. Its trade is humidity.
Humidity is the basement problem
Below-grade spaces run damp, and damp affects everything absorbent: cardboard, paper, fabric, ribbon, wooden decorations, and the cardboard inserts inside most fabric ornament boxes.
Sealed rigid containers handle it well. What does not is leaving containers directly on a concrete floor, which is the coldest surface in the room and the one where condensation forms. Raise everything off the floor — a shelf, a pallet, two lengths of timber. This is the cheapest storage improvement available and almost nobody does it.
Pests follow material, not location
Rodents and insects are indifferent to polyester foliage, glass and plastic. They are very interested in real pine cones, dried berries, citrus slices, raffia, cinnamon sticks, and paper for nesting.
So the pest question is not “attic or garage”, it is “does this decoration contain food”. Remove the organic elements before storage — most are wired on and take minutes — or keep those items inside the house. A fabric container is not a barrier, and once something is inside it, it has a warm dry nest.
The split we would actually make
Inside the conditioned house: glass and heirloom ornaments, the tree topper, ceramic villages, painted and gilded pieces, wrapping paper and ribbon, photographs and cards, anything with real pine cones or berries. Most of this is small and fits in a closet or under a bed.
Garage or attic: the artificial tree, plastic foliage and tinsel, light strands once dry, outdoor decorations once thoroughly dry, stands and hardware, bulk items. This is the volume, and it is the part that genuinely does not care.
That division means the awkward, bulky things go where there is room and the fragile, irreplaceable things go where the environment is stable. It also means the containers you buy for the garage can be chosen on rigidity rather than on gentleness — see bins and totes.
If it has to be the attic
Two practical constraints beyond the environmental ones. Headroom: an attic with rafters often will not take a 19-inch-tall bin, which is why the long, low format matters — the Sterilite Industrial publishes 15 1/4 inches of height against the Stacker's 19 3/8 for the same 27-gallon volume.
And access: everything you put up there comes down a ladder, one-handed. That is the argument for two 66-quart boxes over one 27-gallon bin, and it is a safety argument as much as a convenience one.
If you have none of the three
Apartments and small homes have no attic, garage or basement, and the answer is the space under a bed, the top of a wardrobe and the back of a closet. Those are all conditioned interior spaces, which means they are environmentally better than any of the three locations on this page — the constraint is volume rather than conditions. See under-bed holiday storage and storing a tree in a small apartment.