Mushroom cultivation

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Mushroom cultivation

Welcome to the Tastebridge mushroom cultivation wiki. This page is meant as a combined documentation of the Noisebridge mushroom project, and a simple beginner's guide to doing the same at home. The page is sorted by species (so far only one) and sub-divided by substrate for those species that have been / are growing on more than one different substrate.

Oyster mushrooms

Sawdust substrate


  • sawdust, 50/50 oak/alder
  • gypsum
  • water added to 65% wet weight
  • hydrogen peroxide 3%
  • Spawn Mate SEII
  • mushroom spawn
  • spawn bags

The initial moisture content of the substrate should be measured before start; this can be done by weighing out a small sample of sawdust, drying it in a microwave oven, weighing it again and calculating % moisture like so:

 Wtotal - Wdry = Wwater
 (100 / Wtotal) * Wwater = % moisture

The final moisture content should be around 60% of the total weight, so adding about 65% water will result in appropriate levels after evaporation and addition of gypsum and Spawn Mate. The water should be boiling when it is poured on the sawdust, mixed in as quickly and thoroughly as possible, and the mix then left to cool.

Once the wet sawdust has cooled to <50°C / 120°F, add 3 % by wet weight of a 3% hydrogen peroxide solution, after first, making sure that the hydrogen peroxide does not react with enzymes (peroxisomes) in the saw dust, as this will spoil the disinfective properties. This can be done by mixing a bit of the sawdust with hydrogen peroxide. If there is no fizzing, simply add gypsum and boiling water. If it fizzes, the sawdust will need to be boiled for about 30 minutes to cease enzymatic activity before the peroxide can be added. Also, do not be tempted to add the peroxide to the water before boiling, as the decomposition rate of H2O2 increases massively with temperature.

Once peroxide has been mixed well into the sawdust/gypsum, the substrate needs to be further cooled to room temperature, then supplemented with 7-32% per dry weight Spawn Mate SEII:

(Wdry / 100) * target% = Wsmii

The last step is the inoculation; a relatively high spawning rate is recommended with the peroxide treatment, as mycelial growth will be slowed down somewhat by the peroxide, and by the microbial competition that the substrate has not been sterilized of commercial spawn grown on millet (from Amycel, Inc.), then transferred in 12-13 lbs. portions to XL spawn bags. The mixing can be done in the spawn bags or in a large plastic tote, and the final mix is then put in the spawn bags, which are sealed, preferably with an impact sealer.

Original estimates of colonization rates were about 4 weeks, but these turned out to be overly pessimistic. Our blocks were inoculated on two separate occasions, 21 and 27 July 2011, and the first blocks were fully colonized by July 29th and fruiting heavily by 8 Aug (see photo). Once the blocks are completely colonized (see picture), the fruiting can be initiated either by taking them out of the bags, or by making a bunch of X-slits in the bags spaced about 2" / 10 cm apart and placed in a climate-controlled fruiting chamber. The chamber can be constructed by covering a wire shelf rack with thick plastic, adding a small fan and a humidifier (preferably on a timer so it only runs during day time) - temperatures should be within 15-25°C / 60-75°F, and relative air humidity optimally between 90% and 93%.

Coffee ground substrate


  • coffee grounds from a coffee shop
  • coarse vermiculite (optional)
  • Spawn Mate SEII (optional)
  • mushroom spawn
  • spawn bags

In an attempt to bring mushroom cultivation costs down as low as possible, we wanted to try out coffee grounds as a fruiting substrate for oyster mushrooms, as grounds are (generally) free and plentiful, and easy to come by in urban areas with lots of coffee shops. The initial plan was to use the peroxide technique again, but the peroxide reacted fairly strongly with the coffee, so instead, we tried three different options: 1) pressure cooking + Spawn Mate supplementation, 2) no cooking + Spawn Mate supplementation, and 3) no cooking + no supplementation.

Start out by measuring the moisture content of the coffee grounds as described for the sawdust above. Then add water, and optionally vermiculite for a looser texture.

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