After eighteen months you can't tell the bags apart

Three bin bags in a row, each one shorter than the last. The full one on the left is bulging with this year's leaves. The middle bag has slumped. The one on the right has collapsed to a third of its original height. Taped to each: a single year — 26, 25, 24.

Nothing was done to any of them. That's the entire process, and the tape is there because it doesn't look like one.

What is actually different between these three bags?

Time, and nothing else — the same leaves, the same bag, left alone for a different number of months.

Composting needs a mix of materials, turning and a bit of attention to keep it working. Leaf mould doesn't; leaves on their own break down slowly, through fungi rather than the bacteria that drive a hot compost heap, and the whole process asks for is a bag with a few holes in it and somewhere out of the way. The bulging bag on the left and the collapsed one on the right are the same input at two different points on a very slow, entirely passive curve.

Why does leaf mould need nothing except time?

Because fungal breakdown of tough leaf material is naturally slow, and speeding it up would mean turning the process into ordinary composting instead.

A hot compost heap works fast because it's fed a mix of materials and turned to keep oxygen and heat up — active management, basically. Leaves alone are mostly one difficult material, lignin-rich and slow to break down, so the fungi that do the job simply take longer rather than needing help. Two years gets a genuinely fine, dark material; one year gets something coarser that's still useful mixed into a bed. Neither is wrong. They're just different points on the same bag.

What makes a good leaf mould bag — bin liner, hessian, or wire?

Something that holds its shape loosely and lets air through, rather than sealing the leaves in tight.

A completely airtight bag traps moisture and turns leaves anaerobic and slimy instead of crumbly. A few holes punched or slit into an ordinary bin bag does the job as well as purpose-bought wire mesh or hessian, which is most of the reason bin bags are what actually get used — the material barely matters next to whether air can move through it at all.

Who owns a year written on a strip of tape?

Nobody. A year is a fact, not a mark, and taping one to a bag is the same convention a gardener would use on a jam jar or a seed tin — it belongs to whoever wrote it, and to no one else.

What would be owned, if it appeared here, is a compost bin manufacturer's branding, or a specific product name for a leaf mould bag sold as such — ordinary licensing, the same as anywhere else, if a real one were the point of the shirt. Left as three plain bags and three plain years, the design stays a record of a process rather than an advertisement for a product.

Does this work for a heap instead of bags?

The bagged version and a heap turned into full compost are telling two different stories, even though both are about the passage of time underground.

A heap is one continuous mass with the newest material on top and the oldest at the bottom, so its picture is a single vertical section. Bags are separable, and that's the point of drawing three of them side by side rather than one: each bag is a complete, finished year on its own, not a slice of an ongoing process you'd have to dig into to compare.

Isn't three years' worth of bags just clutter round the back of a shed?

Only if none of them are labelled, which is exactly the problem the tape solves.

Leave two bags of leaves for long enough and they stop being distinguishable by eye — same colour, similar texture, no way to tell which was started when. A pencilled label loses that fight faster, which is the whole reason to write the year somewhere sturdier than a plant tag and check it before the bag gets opened rather than after.

Does it print well?

Yes — three simple sack shapes at graded heights read clearly at a glance, before anyone's close enough to see the tape.

Keep the three bags at genuinely different heights rather than a subtle stepped difference — the gap between full and collapsed is doing the work of showing two years passing, and softening it would flatten the whole point. Cream for the bag outlines against dark green, with the tape and years picked out in orange so the numbers are the last thing the eye lands on, not the first.

How do I get one made?

Describe the bags at JustOG — how many years, how collapsed the oldest one should be, and what to write on the tape. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

Three bags, three years, and nobody who did anything to any of them.