Coffee and contamination

I just checked my other tub containing the coffee and vermiculite substrate, and it's contaminated with a dark green mould.

Both of my coffee substrate experiments fell ill to contamination, which means the substrate itself wasn't adequately sterilised, my mix was poorly created or that it was exposed to other organisms somewhere along the process.

I think for now I should not use coffee grounds in my substrate until I get a pressure cooker and can make grain spawn and try a different combination, such as coffee grounds with straw or wood pellets, perhaps.

I would really love to use coffee grounds since I drink so much coffee and I can help reduce waste by repurposing it, but for now I need to learn some other skills as well as get better sterilisation equipment.