Welcome to Your Mushroom Growing Journey!
You've got your rotterzwam Growkit. But now what? This is your complete guide to turning everyday coffee grounds into circular, home-grown oyster mushrooms. Whether you're a complete beginner or growing a second (or third!) time, you'll find everything you need right here.
Every year, millions of kilograms of coffee grounds end up in landfills, wasting nutrients and producing greenhouse gases. With your rotterzwam Growkit, you're changing that one cup of coffee at a time.
Welcome to the movement. Let's grow together.
STEP-BY-STEP
Growing mushrooms is easier than you think. With a bit of patience, some coffee, and these step-by-step instructions, you'll go from curious beginner to confident urban farmer in just a few weeks.
This website is your companion through every stage of the growing process. We'll walk you through the basics, from opening your kit to harvesting fresh oyster mushrooms to composting spent substrate back into your garden. We troubleshoot the hiccups, and celebrate your harvests.
Starting
Adding Coffee
Challenges
Growing & Harvesting
Another Go!
rotterzwam: more than mushrooms
rotterzwam is more than a mushroom farm: we're a social enterprise on a mission to build circular, local food systems in the middle of Rotterdam.
Founded in 2013, we grow mushrooms on organic urban waste materials like coffee grounds, brewer’s grain and wood chips.
Our mission is simple: prove that cities can produce their own food sustainably, create meaningful networks, and close the loop on organic urban waste streams.
What makes us different?
Circular by design
Did you know that only 0,2% of the coffee bean ends up in your cup of coffee? The remaining 99,8% ends up in the trash.
We collect over 5,000 kg of coffee grounds weekly from organisations in and around the city of Rotterdam, and strive to use it for mushroom cultivation.
When we have too much coffee grounds or coffee that is too old and moldy, we compost it.
Education & inspiration
Through workshops, farm tours, and growkits like yours, we're empowering people to understand where food comes from and how they can participate in creating a more sustainable food system, starting in their own homes.
Most coffee waste comes from people’s homes. As you can imagine, it is impossible for rotterzwam to collect all these coffee grounds.
That is why the rotterzwam growkit is created: it is the next best sustainable option for you, the coffee drinker, to literally give new life to your own waste.
Urban agriculture pioneers
Rotterdam is our laboratory. We're proving that cities don't have to depend entirely on rural farms for fresh food.
Urban mushroom farming is scalable, low-impact, and brings production closer to consumers, which reduces transport emissions and strengthens local economies.
Social impact
Our production facility employs people with distance to the labor market, providing training, purpose, and pathways back into employment.
Growing mushrooms in an urban environment creates jobs, builds skills, and strengthens communities.
Your rotterzwam Growkit is an extension of the rotterzwam mission
By growing mushrooms at home, you're joining a community of urban farmers, circular economy advocates, and fungi enthusiasts who believe that small actions like saving coffee grounds, growing your own circular food and sharing knowledge, can add up to big change.
