Everything fades. Compost shows how.

Compost isn’t dirt or trash — it’s a living system. Tiny workers like bacteria, fungi, and worms break down organic matter into nutrients as the pile warms and steam rises. What was once waste becomes fertile compost through four natural stages: warming up, heating up, cooling down, and maturing — a process nature has perfected over billions of years.

It all begins with organic matter: if it grew, it can usually go back. Fruit and vegetable scraps, coffee grounds, and grass clippings make ideal compost fuel, breaking down quickly to feed the microbes that drive the process. But compost isn’t a free-for-all — anything treated with harsh chemicals leaves residues that don’t belong in healthy soil.

We design sneakers to move with nature’s rhythm, using materials chosen for their biocircularity. That’s why we ask: don’t polish your SOLKs with chemical products. They might shine for a moment, but those residues can disrupt the composting process

When you know what’s going in your compost, the next question is how fast it breaks down. And here’s the trick: microbes need access.

That’s why SOLK sneakers go through the big, mean, hot-pink shredder. It tears them into tiny, ragged chunks, multiplying the surfaces where microbes can start their work. Rough edges are invitations. A whole sneaker could sit around for years; shredded pieces fade in months.

Compost thrives on balance: the right mix of carbon and nitrogen keeps microbes active and the process moving. Too much of one, and the pile slows down or turns unpleasant.

We mix the shredded sneakers with our own Biotop-Felder (conservation meadow) plus coffee grounds and horse manure. The diverse grasses and wildflowers provide fast nitrogen for an early microbial boost. Coffee grounds add even more nitrogen, while horse manure brings a rich community of microbes and helps build structure.

The mixture looks rough, smells sharp, and is far from pretty. But this base blend is exactly what microbes need to get started. Once balanced, Uncle Norbert feeds it into the rocket, where it’s transformed step by step into a finished mixture of pre-compost SOLK-slurry.

When microbes feast, the pile heats up. At 60 °C and above, pathogens are destroyed, and tougher fibers start breaking down. Without control, that heat can swing too high or fall too low, slowing the whole process. That’s why we use the Rocket Composter. Think of it as a compost pile with an engine. Insulated walls keep heat steady, sensors track air and moisture, and agitators turn the mix. Bigger, hotter, and more precise than a garden heap, the rocket transforms our balanced mix into sneaker slurry.

Doesn’t sound like much? It’s a lot. Our goal is to prove that it is clean enough that the existing composting industry accepts it. No red flags. No raised eyebrows. Just a warm welcome. Legislation doesn’t allow this yet, but we’re working on it. A systemic and scalable solution turning kicks into compost.

“Biodegradable” is vague. “Compostable” has rules. For plastics, existing standards in Europe set clear expectations: timely breakdown in industrial composting conditions. Nothing toxic left behind. No heavy metals. No visible fragments. The end product must be safe for plants.

There’s no composting standard designed for sneakers—yet. So, instead of waiting for one, we developed our own. We took inspiration from existing plastic and packaging standards but set our own criteria for every part of a SOLK: the leather, laces, sole, and more. We define the composting timescale, run the process ourselves, and then send the resulting compost for independent lab testing to confirm its clean.

From the shredder’s roar to the rocket’s hum, with Uncle Norbert watching over, every SOLK is fading into something new.