Gardening with Mushrooms

Don't throw that Grow-Kit away!

Whether you’ve already grown out your  grow-kit in multiple flushes, or have just purchased one and are planning ahead, we are excited to have compiled all the information you need to add your spent farm block into your garden! Below you will find the best of the best advice from permaculturists much more experienced than Brad and I on how to continue growing oyster mushrooms with various easy methods you can adopt.  

One note here is that Lion’s Mane is unlikely to continue growing in your garden. Lion’s Mane requires very clean inoculation conditions and sterilized grow media and we have personally not successfully fruited them in our compost or garden. All our oyster varieties do continue to grow all summer in both our compost pile and garden. So without further ado, happy garden planning! 

We are going to cover three of the easiest ways to incorporate your spent grow kit block into your yard, garden, or patio to continue fruiting mushrooms all summer long: 

  1. Making mushroom beds 
  2. Growing in containers
  3. Mulching your garden with straw 

These methods are some of the easiest, most reliable ways to grow mushrooms outside. We are going to show you how to do each of these methods using straw and cardboard. If you do not have a grow block, you can also grow these methods using our farm compost! Stay tuned to social media as it is available by donation in the Spring! 

Preparing the Terrain

Preparing your growing substrate is the most critical phase of the setup, and if you get it wrong, you’ll have to start again. The idea behind setting up your growing medium is to provide the mushrooms with everything they need to grow while keeping out other microorganisms that compete for the same nutrition.

Cardboard and Straw – As the most commonly used substrate, straw is cheap and features all the necessary nutrients to grow your mushrooms. Pasteurize the straw by soaking it in hot water (149 to 176F) for around 2-hours.

Making mushroom beds

Cardboard and straw mushroom bed

Select an area that is shady in your garden, yard, or under your deck.

  • Clear the area of any weeds and grass so that you have a nice area of fresh top soil.
  • Lay down a layer of cardboard to stop weeds and grass from quickly growing through your bed and competing with the mushroom mycelium. The cardboard will also help retain moisture.
  • Lay down an even layer of your shredded and sterilized straw covering the cardboard completely.
  • Break apart your grow block. Do not pulverize it, it is alive, simply break apart into ¼ to ½ inch chunks.
  • Spread half the block on top of your straw.
  • Make another layer of straw on top.
  • Spread the second half of the block.
  • Top with a third layer of straw.
  • SOAK the entire thing with a good amount of water.
  • Cover with clear plastic (garbage bag, poly, or some other clear plastic) for the next few weeks only as it colonizes to help maintain moisture. ENSURE YOU CUT PLENTY OF SLITS IN THE POLY TO ALLOW FOR AIR EXCHANGE.
  • Continue checking on the moisture level over the next few weeks as it colonizes watering whenever it needs.
  • Once you see mushrooms begin to emerge, remove the poly and allow the mushrooms to fruit through the straw uninhibited.
  • Keep an eye on the moisture, and harvest once gills open and mushrooms begin to brown on the edges.

One of our favorite mushroom channels is Fresh Cap Mushrooms, Tony has an amazing video you can reference for more details and troubleshooting this method here:

Growing in containers

Mushroom Container

If you do not have an outdoor garden space, fear not! You can recreate the exact process in a bucket or laundry basket for your patio or walkway.

The containers you inoculate in should have some airflow. If you’re using a plastic bucket, drill some holes into it. Most folks create a diamond pattern every few inches, ¼” diameter works well. Remember to put a few in the bottom, too, so excess moisture can drain out. We tried out using laundry hampers and plastic growing pots with great success.Once properly hydrated, pack the straw into some containers, sprinkling broken up grow kit or compost in between each layer. The top layer should just be straw. Alternatively, you can mix your straw and spawn on a tarp and pack them all into the bucket at once. Cap it, and let it grow!

It’s easy to place these containers throughout your garden, maximizing how much you can grow in your space. Not only that, but mushrooms growing alongside your plants creates a mutually beneficial gas exchange. Plants photosynthesize, so they take in CO2 and release O2, while mushrooms respirate like us, taking in O2 and releasing CO2. We’re curious about the fungi/plant gas exchange and how it could be especially useful in a greenhouse!

Again, Tony has a great video here:

Mulching your Garden with Straw

The simplest of methods by far, repeat the same process for a mushroom bed in between rows of shading giving plants. Mulching a potato or squash bed is ideal. Our mushrooms fruit under all of our squash and cucumbers due to the amazing shade they provide.

Mulched beds can be lighter than the mushroom bed above to keep from burying your plants. Just remember to give it all a good soaking when you’re done. Fungi need a moist environment to grow.

As your garden grows, your plants will provide shade to your beds – mimicking the forest canopy of their natural environment.