top of page
  • Writer's pictureJeremy Wright

Brewing Success: Using Coffee Grinds as Mushroom Substrate

Welcome, mycologists and mushroom enthusiasts, to an exciting exploration of an unconventional yet highly effective substrate for mushroom cultivation: coffee grinds! In this blog post, we'll uncover the benefits of using coffee grounds as a substrate, explore the step-by-step process of preparing and inoculating coffee grounds with mushroom spawn, and discover the magic of growing your own gourmet mushrooms from this readily available resource.

Why Coffee Grinds?

Coffee grounds, a byproduct of our daily caffeine fix, possess several qualities that make them an excellent substrate for mushroom cultivation:

  • Nutrient-Rich: Coffee grounds contain essential nutrients such as nitrogen, potassium, and phosphorus, providing an ideal environment for fungal growth.

  • High Moisture Content: Coffee grounds retain moisture well, creating a favorable habitat for mushroom mycelium to thrive.

  • Readily Available: Coffee grounds are abundantly available from coffee shops, cafes, and home brewing activities, making them a sustainable and cost-effective substrate option.

Step-by-Step Guide to Cultivating Mushrooms on Coffee Grinds:

1. Gather Your Materials:

  • Fresh coffee grounds (ideally used within a day or two)

  • Mushroom spawn (commonly available online or from specialty suppliers)

  • Large mixing container

  • Plastic bags or containers for incubation

  • Sterilized utensils (spoon, gloves)

2. Prepare the Coffee Grind Substrate:

  • Collect a sufficient amount of coffee grounds, ensuring they are not too compacted.

  • Place the coffee grounds in a large mixing container and allow them to cool to room temperature if they are fresh from brewing.

3. Inoculate with Mushroom Spawn:

  • Gently mix the mushroom spawn into the coffee grounds using sterilized utensils until evenly distributed. The spawn can be in the form of grains, sawdust, or plugs.

  • Ensure that the spawn is well distributed throughout the coffee grounds to promote uniform colonization.

4. Incubate the Substrate:

  • Transfer the inoculated coffee grounds into plastic bags or containers, leaving some airspace for gas exchange.

  • Seal the bags or containers and incubate them in a dark, warm environment (ideally around 70-75°F or 21-24°C) for several weeks to allow the mushroom mycelium to colonize the substrate fully.

5. Fruiting and Harvesting:

  • Once the coffee grounds are fully colonized with mycelium, small pinheads will begin to form.

  • Provide proper humidity and ventilation to encourage the growth of mushroom fruiting bodies.

  • Harvest the mushrooms when they reach maturity, typically by gently twisting and pulling them from the substrate.

Tips for Success:

  • Use Fresh Coffee Grounds: Freshly brewed coffee grounds are preferable, as they contain more nutrients and have not been exposed to contaminants.

  • Maintain Proper Hydration: Ensure that the substrate remains adequately moist throughout the incubation and fruiting stages by misting with water as needed.

  • Monitor for Contamination: Keep a close eye on the substrate for any signs of mold or bacterial contamination, and remove any affected areas promptly.

  • Experiment with Different Mushroom Species: While some mushroom varieties, such as oyster mushrooms, thrive on coffee grounds, others may require different substrate compositions.


By harnessing the potential of coffee grounds as a substrate, you can transform your kitchen waste into a bountiful harvest of gourmet mushrooms. Whether you're a seasoned mycologist or a curious beginner, cultivating mushrooms on coffee grounds offers a rewarding and sustainable way to connect with the fascinating world of fungi.

So, grab your coffee grounds, roll up your sleeves, and embark on a mushroom-growing adventure that's as satisfying for your taste buds as it is for your soul.

Happy Cultivating! 🍄☕️

8 views0 comments

Recent Posts

See All


Post: Blog2_Post
bottom of page