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Growing Mushrooms (2020-)

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Shopping List

Fred Meyer/Target

  • 60 qt clear tub - I like the style with the locking lid so the lid can’t accidentally pop off
  • alcohol wipes
  • Large (maybe 50 gal.) black garbage bags. You want the bottom of the bag to fit nicely into the bottom of your tub.
  • 70+% alcohol
  • lighter




  • 1 syringe of mushroom culture.


Monotub Construction

You’ll see lots of different preparations online for the monotub. I really dislike the look of the large-hole, loose polyfill style that’s common. I found a video where a guy described a convection style setup with holes along the top and bottom so I went with that. YMMV.

  1. measure up 4.5" and cut 4, 1" holes on long sides
  2. measure down 3" and cut 2, 1" hole on short sides
  3. tape over holes with micropore tape from the inside of the tub.
  4. tape over holes again with painter’s tape from the OUTSIDE of the tub.
  5. Tape over any other holes with painter’s tape from the OUTSIDE of the tub


I would recommend watching a bunch of videos online that go over sterile techniques so you’re mentally prepared for this crucial first step.

  1. Spray everything down with Alcohol
  2. Get the syringe needle red hot with your lighter
  3. Wipe the needle down with an alcohol swab
  4. Inject the spawn bag from several different angles. I used the whole syringe on my 1st 4lb bag. Next time I might try injecting the bag while it’s upside down to get more of the liquid into the top section of the bag.
  5. Mark your bag with the inoculation date
  6. If you purchased the seed warming mat then put your spawn bags into your monotub on top of the warming mat and set it to around 75ºF. Otherwise just put your bag someplace warmish. It should take 5-6 weeks for the bag to be ready to transfer
  7. One thing you can try during this phase is to completely break up the solid spawn when it’s taken over about half of the grain in the bag. This redistributes the spawn throughout and seems to speed up the process a bit.

Transfer to monotub

I found out during the process that my garbage bag was slightly smaller in its base than the tub which made this process more awkward than it needed to be. I like the way this guy builds up the bag from the outside first but I haven’t tried it yet.

  1. Place your garbage bag into the tub and cut it down so it will sit in the tub just below your bottom air holes
  2. Sterilize tub
  3. Temporarily tape the bag into place
  4. Sterilize the inside of the bag
  5. completely break up your spawn bag, without opening it, so there are no more clumps
  6. Dump a layer of substrate into the lined tub
  7. Layer in some spawn
  8. Repeat until you’re out of spawn and substrate
  9. I chose to completely mix everything together and that seemed to work fine. Some people don’t do this
  10. Give the surface a good misting
  11. If you purchased the temperature and humidity sensor then just place it in the tub and set its humidity alarm to 85%.
  12. Close the lid and put the tub someplace warm
  13. Mark the tub with the date
  14. Keep misting throughout the growing process. You want to have little beads of water on the surface at all times. Having condensation on the lid and sides is a good indicator that the humidity is good.
  15. When you start to see “pins”, remove the painter’s tape on the outside to allow gas exchange.


The first harvest may come as soon as 2 weeks after transfer to the monotub. I use a short, very sharp knife to cut the largest mushrooms away from the cluster. Mainly grab any that have started to open their veils.

Once the growth seemed to mostly stop I pulled up the bases of all of the cut stalks to clear the substrate surface. I mixed together some worm juice and water and rehydrated the entire substrate. ⚠️ The worm juice appears to have been a mistake as I got one small final flush and then all growth seems to have stopped. I’ll rehydrate with just water next time.


12 hours @ 115F in a dehydrator works great. The dried mushrooms should be as dry as a cracker before they’re stored. If you want to powderize them a high-speed blender seems to work best. You’ll want to put some kind if desiccant into the jars with the powder to prevent clumping.