Q1:)  I have done some more reading and have a good idea for how to sterilize/pasteurize the substrate. We have loads of wood shavings as I have a small stable yard and use it as bedding. I can also get barley hay from my one supplier which has been chaffed (will this be ok?)

We have a stable block of about 50 square metres which I can eventually turn into my mushroom room (lol). Would it make do? My husband would also like to know how labour intensive (staff required) this endeavour is…obviously that would depend on how large your little home operation gets… but if you could help us with a general idea. Also there seem to be conflicting views as to how easy/difficult growing these mushrooms is. We would just like to start with our eyes wide open.

A:) There are 4 ways of going about things in the mushroom industry:

  1. The button mushroom industry – using fermented straw – well composted straw to spawn and supplemented with animal manure etc.
  2. Large scale exotic mushroom production using massive autoclaves, and in some cases machinery to complete the inoculation cycle
  3. Smaller home businesses, having their own cleanroom and steam facility to achieve sterilization and inoculations.
  4. The hobbyist and beginner – pasteurizing wheat straw – inoculation in a cleaned room – but not sterile.

I was the number 4 starter when we began growing oyster mushrooms and since have moved to number 3. If you start at number 4 – you will need clean, fresh chopped wheat straw (depending on the size of the straw shafts, barley chaff may become soggy with addition of water, you will have to add this sparingley). By submerging the straw in 65 degree Celsius water for 90 minutes, you will achieve pasteurization. The substrate is now removed from the water, left to dry and cool down in a small cleaned room for about 2 hours. Once the straw temperature has dropped to 25, you can inoculate by sprinkling your seed spawn over the straw. Mix the seed in and pack this in clean, translucent bags. Close the bags and punch holes for air. The bags are then incubated for 10 1to 14 days at 21 degrees.

As with cooking, there is a recipe to produce oyster mushrooms, if you stick to the recipe, and allow for no contamination entry, it becomes a breeze to cultivate fungi. They are all different, and prefer different environmental factors to be in place before fruiting. In warm weather, the oyster mushroom becomes lazy and often takes longer than usual to fruit.

When using wooden substrates, you will need hardwoods – black wattle is fine, oak is fine, poplar is fine but you cannot use pine. Oyster mushrooms do not like pine at all, and will show no growth after inoculation. I would suggest none of the aromatic woods for mushroom production. I am yet to experiment with using blue gum, this as a substrate have often surfaced with some indignity, it appears the substrate may impart some chemical to the mushroom growing on it that have reportedly caused nausea in some people.

When using wood substrates, you will need to steam sterilize pre packed bags, steaming them at 100 degrees Celsius for 6 hours. The bags are then cooled in your clean room for 24 hours and then inoculated in front of a laminar flow hood. The air is filtered by a .3 micron HEPA filter to ensure sterile air flow.

Your grow space will need to be well ventilated as oyster mushrooms need plenty of fresh air. You will also need to protect your bags from the fungus gnat – a hardy little fly that is attracted by the smell of your mushroom mycelium. I give my mushrooms 12 hours light a day and use ultrasonic humidifiers to keep humidification in the high 70's. You will have to do some work on preparing your stable block into a mushroom grow space ...

It helps to have two people running a small operation, to help with inoculations, substrate preperation etc.

Start small, keep it simple and decide from there where you would like to take it. Some people have a hand for growing mushrooms and understanding their needs, the only way to find out is to try.

Q2:) How do you deliver your orders and how long does it take?

A:) We use SAPO domestic parcel service for most deliveries. It offers tracking and delivery time is usually between 4 and 5 working days. In some cases it have taken 14 days due to strikes in SAPO system. We use Triangle couriers for Spawn deliveries in the Garden Route and most of the Western Cape.

Q3:) I want to grow mushrooms, but I know nothing about them, where do I start and can it be profitable?

A:) Oyster mushrooms are by far the easiest crop to grow. I always suggest people to start there. The process of pasteurizing wheat straw and spawning that with oyster mushroom culture is relatively easy and can be the most profitable. Using straw as a substrate I have had 60% returns in usable weight mushrooms from the weight of the substrate. Every 15kg straw should give you at least 8 - 10kg of mushrooms.

Q4:) How much spawn do I use to inoculate my Oyster mushrooms?

A:) You can inoculate at 10% - 15% the substrate weight. If your wet weight of pasteurized straw is 5kg, you can use 500gr of spawn. If your sterilized bag weighs 1.5kg, you can use 150gr of spawn.

Q5:) I've never grown mushrooms before and also don't really have the budget for expensive equipment. I have read that you can grow on plain used coffee beans. My questions are, will this work form me?

A:) Oyster mushrooms have successfully been grown on coffee waste, wheat straw, corn cobs, wild grasses, hardwood shavings, waste paper and a mixture of all these.

Q6:) Can you continually harvest mushrooms from the same plant?

A:) After inoculating your substrate, the mushroom mycelium will slowly start consuming the food source. You can expect 4 - 5 flushes of mushrooms from each bag. As the food source becomes depleted and water becomes unavailable to the mushroom mycelium, it will stop producing altogether. The fungus can live on agar or seed for storage, mostly up to 2 months refrigerated. From there you will need to transfer the culture again for further storage. It is fairly easy to clone from an existing oyster mushroom as well. Or to grow a new culture from spore.

Q7:) What do I need to consider before starting to grow Exotic Mushrooms?

A:)  Understanding the environment mushrooms like to grow in is one of the first factors to consider. Once you have regarded all the growth factors of a particular mushroom, you can go ahead. Saprophytic mushrooms need a suitable food source. They need fresh air, light and the correct temperature to fruit. I believe the presence of nitrates in the soil, will also bring forth flushes of mushrooms, as after a thunder storm. Mushrooms like water, but not too much water either. Too much water will bring about anaerobic conditions, and this will have a proliferation of bacteria soon to follow. It is advisable to find a suitable substrate that is easily available in a 50km radius from where you plan your mushroom grow space. Bringing in substrates over vast distances will have transport costs that may influence your profitability.

Q8:) How do you plant mushrooms? When can I plant mushrooms?

A:) To answer this question I have to start at the beginning. Mushrooms are fungi, and produce spore, or reproduce by mycelium moving to new territories. The fungi genus is completely separate to the plant genus. To make things easier to understand, we could say that a dried log can be inoculated, or a garden mushroom bed can be inoculated or my substrate (food source) can be inoculated with a mushroom culture, mushroom spawn or mushroom plug spawn.

Plug spawn can be used to inoculate cut logs outdoors. These wooden dowels are inoculated with shiitake culture or spawn and then inserted into pre-drilled holes in cut oak logs. An outdoor mushroom bed can be created in your vegetable or flower garden. You can inoculate your outdoor mushroom bed with King Stropharia spawn, these are giant mushrooms that can easily grow outdoors.

Different mushrooms havedifferent likes and dislikes. In nature mushrooms have their seasonal time, when all the environmental factors are just right for the mushroom to fruit. Unless you have a completely controlled environmental system, to house your mushrooms, it is best to choose the right species to produce in the right time of year.

Pink Oyster mushrooms does not like cold and temperatures lower than 6°C can cause complete inertia in this species, therefore I prefer cultivating this mushroom species in spring and summer. In summer I get the most vivid pink color from these mushrooms and the colder it becomes towards autumn, the more faded the pink color becomes, untill eventually an almost white color appears in winter time with extreme slow growth and barely any fruit.

The Blue winter Oyster on the other hand prefers to grow in autumn and winter time, the cold causes a shock to the mushroom mycelia and produces pinning - the beginnings of the newly formed mushrooms. In summer I find the winter oysters becoming lazy, fruiting occurs, but is much more sporadic. The mushrooms harvested from our winter oyster mushroom logs in summer have a shorter shelflife and produces a higher sporeload.

Some strains of mushrooms i.e. shiitake, have a wide preference for growth and can be produced right throughout the year. There are also strains of shiitake that prefer either winter or summer available from culture libraries. 

Q9:) I enjoyed browsing on your website, some handy tips. Have you or do you know of anyone who has used Port Jackson for substrate? I made a few bags with the winter oyster, but they are taking a bit too long for my liking. It is very cold here and am struggling to keep them at a constant temp.

Any hints for quicker colonization? I got a big bag of oak sawdust from a local joinery, was thinking of mixing some in. Any ideas of how I can heat my incubation room with only a few degrees? I guess adding more grain spawn would also help..

A:) I have never used Acacia saligna myself; but the general rule is that broad leaved, non-aromatic woods will work. For Oysters Poplar is a good wood source, but I have used Forest Alder, Black Wattle, Oak, ironwood, white pear and some other local trees. I get my shavings from a rustic furniture factory. It is non-treated and poison free. Tree types to avoid: Pine, Yellow Wood cypress etc.

Oysters love straw; I add straw chips to my wood mix to help the mycelium run through the substrate. The small chipped straws act as pathways between parts of your substrate and also allow for better AIR distribution.

While incubating two things are very important, temperature and air exchange. Incubation is best at temperature of 18 deg and above towards 21. If your mycelium runs out of air in the substrate bag, it will slowly grow to a halt. I use a 275 and a 400 Watt, wall panel heaters in my incubation rooms. These are on a thermostat to avoid overheating.

How did you pack your bags, what size are the bags and how did you sterilize your substrate?

Shiitake loves Oak - the other name for it - GOLDEN OAK MUSHROOM.

Q10:) . I pasteurized above 70 degrees for 2 hours. 2-3kg bags. We have lots of port jackson here and would like to figure it out. There is solid growth, but I know it can do better. I can get poplar from a friend, going to try make a mix for the next batch. If i can get straw I will mix some in aswell.

Is it better to dry the substrate after chipping, before pasteurization? If i use shavings with the chips, do I pasteurize the mix together?

A:) I had real bad luck every time I tried to pasteurize my wooden substrates - it seems that if you only use straw pasteurization is fine - at least unsterilized substrates needs to be treated with hydrogen peroxide first - or better - pre mix the substrate to its perfect moisture level include your supplements and then bag it, steam the bags at 100 degrees for 4 - 5 hours. This way you know every bag is sterilized and your moisture content is perfect. Then I inoculate in a clean space.

When using freshly cut wood shavings, make sure it rests for 2 weeks in a dry space before use. The wood's natural anti-fungal agent needs to break down, before the mycelium can start to penetrate. Then mix all ingredients, add water to the right moisture level - 60%. Never must there be any free water in substrate; the substrate must be damp, not wet. Too much water will invite contamination.


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