mycofarm

Boosting yields: growing on bulk substrates (straw)

The MycoFarm produces enough for most hobbyists. However, if you would like to invest more time and effort then you can try growing on bulk substrates. There is quite a bit of work involved with this method but the yields can be huge... Additional equipment and time are needed. Not recommended for beginners.

The idea is to take your colonised bag of grain from the MycoFarm and use it to inoculate a much larger amount of bulk pasteurised substrate (in this case, straw treated in a hot water bath). This method works because cooled straw is clean enough to allow the mushroom mycelium to rapidly colonise it before other organisms can.

The straw logs are then fruited to give many more and much larger mushrooms. With some species of mushrooms it is also possible to add a casing layer (not shown here).

opened kit showing bag swab and syringe

1. Get hold of a metal drum (it must be food grade - this 20 litre vegetable oil can was kindly donated by a local takeaway). If your drum is made of thin metal, you can chop the lid out using a hammer and chisel (easier if you chisel at a slight angle). A 20 litre drum is about the smallest that is worthwhile and one pillow case of straw fits - just. Get a bigger one if you can - 55 gallon oil drums can be used if you are really ambitious. Top tip: You will be left with sharp edges after chiselling - use pliers to crimp them as best you can or it will catch on the pillowcase when you remove it).

swab black rubber injector port with wipe

2. Get some straw from the local petshop - a minibale (approx 2 kg) of straw is plenty (usually wheat is recommended but barley works fine and is easier to work with). 1 kg of dry straw will fill one pillowcase and give you enough for two straw logs. Cut bale in half. Half goes in pillow case and half in bin bag for later.

inject bag via black rubber injector port

3. Add 10 litres of water to drum and heat to 70 C. A propane burner is best for this and you may want to do it outside. An inexpensive dial thermometer is essential for this process to work correctly as the temperature throughout is important

4. Lower your pillowcase in and push down slightly. Water will not quite cover it. Add an extra 4-6 litres of hot water until is is just covered.

5. Place a metal plate and a brick on top to hold pillow under water. Maintain temp at 70 C for at least 1 hour.

6. Drain for approx 1 hour.

7. Put a couple of bin bags or plastic down on a flat surface and spread straw out.

Let it cool to 25 C

8. Take your colonised MycoFarm rye bag and gently massage contents through the plastic to break up the grain. Cut the top off the bag when you are ready to proceed. Here we used Branching Oyster (P.cornucopiae).

9. Wearing gloves add straw to large humidity tent.

Add a few handfuls of straw and compact it down slightly. Once you have about 5 cm add a small handful of grain (20-40 kernels is enough). Then add more straw and build up layers in this way.

Top tip: Don't use too much grain initially or you won't have enough for both bags.You'll have to compact the straw down to get it all in. This is desirable. Seal the tops of the bags with packing tape or similar.

10. One MycoFarm rye bag (650g) will easily inoculate 2/3 of these straw logs. Put them at the correct temp for your species (20-24 C for cool weather oyster and 26-28 C is for tropical oysters) for approx 2 weeks

11. This is what happens 2 days post inoculation. You can see the white fluffy mycelium growing from the grain and into the straw.

12. Bag One (fruited in a Vitopod at 21 C with thermostat). The base was covered with a layer of damp perlite and the vents left open. Yield 336g (first flush)

13. Another view of the same straw log.

14. Bag Two (fruited in a storage box with plastic loosely draped over it at room temp, 14-20 C) Yield approx 180g+ (first flush)

15. You can get many flushes if you keep the straw moist with a sprayer or dunk it in a bucket of water for after each flush.