Deep bedding: ten inches, and how to get there

PDSA publishes at least 25cm — ten inches — of bedding for a hamster, and the San Diego Humane Society publishes at least six inches with eight to twelve best. Ten inches over a 775 square inch floor is about 127 liters of substrate, which is one and a half 85-liter bags. The enclosure has to have solid walls to at least that height, which is why most wire cages cannot do it at all.

Deep bedding is the single change that most improves a hamster's environment per pound spent, and it is the one most often skipped, for a reason that is not about willingness: most cages physically cannot hold it. A wire cage with a four-inch plastic base caps you at four inches whatever the wire above it does, because substrate spills through bars.

Why depth rather than just area

A hamster's natural behavior is burrowing, and a burrow is a structure with separate chambers: a nest, a food store, a latrine, connecting tunnels. Given ten inches, a hamster builds that. Given two, it cannot, and the behavior has nowhere to go.

This is why we say floor area and bedding depth are the same requirement in different units. Ten inches of substrate in a 480 square inch base is not a burrow system — it is a deep box in which the animal can dig one hole. A tunnel needs to run horizontally as well as down, and horizontal run needs floor. The two figures select for the same thing, and our cage size guide covers the other half of it.

How much substrate that is

Two 85-liter bags to fill one enclosure once is a cost most people do not expect, and it is the main reason we weight pack size so heavily in best hamster bedding. It is also why aspen matters: at these volumes the price per liter stops being a rounding error.

Making a tunnel hold

Dry substrate collapses. The single technique that changes deep bedding from a pile into a structure is light damping.

1. 1.Mix the structural layer in a separate container — a bucket or the empty bag — rather than trying to damp it in place.
2. 2.Add water a little at a time and mix. The target is substrate that clumps when squeezed and falls apart when you open your hand. Nowhere near wet.
3. 3.Pack it in layers, pressing each down lightly, rather than tipping the whole lot in.
4. 4.Leave the top three or four inches dry, in paper. The hamster starts digging here and dry material is easier for it to work.
5. 5.Let it stand for a few hours before the animal goes in, so any excess moisture distributes.

Too dry and the tunnel collapses behind the animal. Too wet and you get mold, which is a worse problem than the one you were solving. The window between them is wider than that sounds — if it smells of nothing and feels barely cool to the touch, it is right.

Layering, which is the setup that works

• Bottom six to seven inches: aspen, lightly damped. The structural layer, doing the mechanical work, at the lowest cost per liter.
• Top three to four inches: dry kraft paper. Where the animal digs in and where you can see the state of things.
• Latrine corner: absorbent paper, changed every two or three days. The only part that needs frequent attention.
• Nest: plain loose toilet paper, never fibrous nesting fluff — see safe and unsafe hamster bedding.

What deep bedding needs from the enclosure

Solid walls to at least ten inches. That is the whole requirement and it is why the enclosures that clear the floor-area minimum are also the ones that can hold this: the two specifications select for the same design.

If your cage cannot hold ten inches, add as much as it will hold and treat that as a genuine improvement rather than a failure. Six inches beats two by a wide margin. And the cheapest route to full depth is a converted storage tub, which usually has more usable wall height than any purpose-built enclosure at the same price.