King Oyster Mushroom Grain Spawn - UK


The King Oyster mushroom produces thick, meaty fruitbodies which are highly prized for their amazing flavour and unique meaty texture. 

Sometimes called King Trumpet or Eryngii, this species prefers cooler fruiting conditions (12 - 18c), and is more difficult to grow than other Oyster mushroom verities.

This spawn pack includes:

  • 2.8kg of quality King Oyster mushroom grain spawn
  • 20 x Mushroom cultivation bags (can hold 1.5-2 kg substrate per bag)

Difficulty: Medium - Advanced

King Oysters are best suited to growers who have a bit of experience. They are fast to colonise, but can be more fussy at the fruiting stage; requiring lower fruiting temperatures, and consistent humidity.  

Some growers like to use a casing layer but this is not necessary if you maintain good humidity.


  • pasteurised straw
  • straw pellets or hardwood fuel pellets
  • sterilised supplemented sawdust

Growing Parameters:

  • Incubation: 20 - 24C, 12 - 15 days + 30 days ripening phase
  • Fruiting: 12 - 18C, 90 - 95% R.H, <1000ppm CO2
  • Harvest: 4 - 7 days after pinning, 2 crops with 10 days between each flush

    Who Is This For?

    This is for anyone who wants to get involved a step further than our super simple GroCycle Kits.

    With this spawn pack, you can do the whole process yourself, inoculating a bulk load (around 30-40kg) of pasteurised straw or sterilised supplemented sawdust.

    There are no instructions; you'll need to already know how to grow mushrooms.

    If you don't know how to grow mushrooms and you want to learn, then either:

    A good place to start is with our Ultimate Guide On How To Grow Mushrooms

     Important Information

     Note: The spawn contained in this pack is alive and should be used within 1 week of receiving, or can be stored in the fridge for up to 1 month.

    • Free 2-3 day delivery (UK Only)