I recently picked up some spent mushroom substrate (straw) as it was offered for free. Now I’m wondering how best to use it? Do I compost it? My only issue is that I don’t have the greens to match, and my little compost pile just recieved a load of browns recently. Do I mulch with it? I currently have a chip mulch in my garden but I’m open to layering the straw on top. Would an impending Canadian winter affect it negatively, or should I keep it bagged up until spring? Alternatively we have a berry patch that could always use mulch. It looks like I can grab another batch of this size if it’s worth doing. This is new for me, so any advice would be appreciated. TIA

by 4FuckSnakes

7 Comments

  1. toucan_enough

    Do you know what type of mushroom?

  2. LairdPeon

    I’d use it as mulch. If you’re balancing your compost it’ll throw it off.

  3. anntchrist

    It should be fine for mulch, but the wonderful folks over at r/composting will have some good ideas for you if you want to go that route. I don’t know if it is the same in Canada, but in the US our major (global) coffee chain gives out spent grounds for free as a matter of corporate policy, there is often a bin that you can pick them up from (no purchase required), and many small coffee shops will do the same gladly to divert what would otherwise just go to the landfill – coffee grounds are a great source of greens to balance out all the browns, and will really get compost heated up quickly. The more mass the better in a compost pile going into winter.

  4. jh937hfiu3hrhv9

    That looks like it might still have viable mycelium. If you find out what kind of mushrooms they were growing, you might be able to inoculate the correct substrate and get a load of gourmet mushrooms. Otherwise the straw will be mostly broken down and make a good carbon adjunct for compost. The only mushroom I am aware of that inhibits green growth is the oyster mushroom. That should be fully composted before adding to a vegetable garden.

  5. secretbaldspot

    I used spent mushroom substrate one year as mulch. Best year ever. Big yields, low weeds

  6. SpiritualPermie

    The straw tends to be washed/ cleaned with Hydrated Lime before inoculation. If you have worms in your bins, best not to use as compost material. I have read that these can be inoculated for mushrooms over and over.

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