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
TODO: A little information about these muchrooms...
 Sawdust substrate
- sawdust, 50/50 oak/alder
- 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.
This works with a box about yay big, so high, made of stuff, and filled with things...
- this step
- that step
- and then
- and so on...
First we need to see if the sawdust peroxide-decomposing enzymes are active or were destroyed. This can be done by mixing a bit of the sawdust with hydrogen peroxide. If the enzymes are sufficiently denatured that there is no fizzing, we simply add the proper amount of boiling water (as determined by achieving a 60% moisture content) and gypsum.
If there still are enzymes present in the sawdust--and this is the more likely scenario I think given they chip fresh trees at Lazarri--then we must add the water and let the sawdust cook for about 30 minutes or so. It needs to get a core temperature hot enough to denature the enzymes (close to boiling for about 15 minutes would do it I figure). A pressure cooker would be ideal for this so we can mix the proper water content without it lowering through the cook and get the stuff hotter faster, so I will bring two of them in case.
After the cool and once the mix is cool enough to handle in some fashion without the water vapor burning us--we might want to spread it out somehow for the cool down so I'll bring a solution for that too--then the peroxide can be added. Once peroxide has been mixed well into the sawdust/gypsum and provided there are little to no decomposing enzymes still functional, the substrate will be safe to bag up in spawn bags where it can further cool to room temperature (no sealing is necessary since the hydrogen peroxide will protect it). I would like to make about 10 8-pound spawn bags worth (80 pounds).
The next session and phase will be to inoculation the fully-cooled spawn bags. This is done by adding a measured amount of well-broken-up spawn (have to look this one up) and about 4% per dry weight Spawn Mate SEII. The mixing can be done in the spawn bags or in a large plastic tote but the final mix is put in the spawn bags, which are further sealed (I might be able to get some much cheaper spawn bags without filter patches for this work on Ebay before next week). Colonization of oyster bags takes about 4 weeks, so that will be all there is to do to the bags for awhile after the bags are loaded.
At some point during this colonization time, the fruiting shelving must be constructed (they cost about $30 at Costco for a unit I think large enough), and they must be covered with plastic furniture covering, which is very inexpensive at Wal-mart. We'll need to hook up an ultrasonic humidifier with timer and a PC fan for internal circulation as well. Oysters aren't too picky about anything, but they do need ambient relative humidity above 85% or so and some circulation of the air.
Let teh robots do it!
The two critical factors for monitoring are temperature and humidity. There is a readily available combined sensor for this, in the form of a DHT11 for less than a few dollars. However, the near 100% humidity environment is outside the operational range of this sensor. This sensor would be suitable for monitoring of the ambient surrounding indoor environment. There is a newer version of the sensor, a DHT12, this is smaller and the same price, with a functional range of 95% humidity. Alternatively a DHT22 has a full range of up to 100%, and better overall accuracy and sensitivity. These sensors are a little more than a few dollars and are also available as AM2302 which has short wire lead extensions. All of these sensors are 3-5 volt compatible and use a pair or wires for power, and a single data pin for I2C communication. A pull-up resistor of >5K Ohm may be needed, not that an internal pullup on a micro-controller is generally sufficient.
For sample code see: ESP8266/DHT
 Temperature Control
Simply locating within a home that maintains a generally consistent room temperature can be sufficient. In other cases a heating and/or cooling element may be needed. A simple solution could be the use of a heating pad.
In this particular case the use of a peltier device will be considered. These devices have the ability to "pump" heat into or out of a relatively small contained area and are often used in portable temperature controlled coolers. They are available in a range of sizes for a reasonable price and are also fairly energy efficient. They are available at different voltages, often around 12 volts, and can range from a few 100mA to several amps.
For controlling the temperature a pair of relays can be used, switching on a current flow to either increase or decrease the temperature. A cooling fan and large heat sink should also be implemented to increase efficiency and thus turned on with a relay when the system is running. A thermister should additionally be attached in contact with the peltier to monitor/limit maximum operating temperatures.
 Humidity Control
The humidity can be increased as needed with a "cool mist" or ultrasonic style humidifier. These humidifiers are readily available for $10-30. They can be controlled with a relay and run for many hours with a built in reservoir. An additional sensor could be considered to monitor the water level, however in practice this wouldn't be necessary to check other than every few days.