6. Is mine a dud?

Probably not. Your mushroom grow kit is made as part of a batch of about 10-15 bags. So, if it were a dud it would probably mean that the entire batch is similarly affected. Because of the cost involved in replacing a batch we are highly motivated in maintaining strict quality control. However, if it did turn out that we had made a bad batch and we would know that quickly (as we keep and observe a control bag from each batch), we would replace the bag without hesitation.

Environmental Factors: Generally, any issue with an individual bag is usually related to the unique variables in your home. These signs often include:

Contamination: Less frequently we will encounter some contamination like mould. In most cases, the mould will clear up, as healthy mushroom mycelium will either contain or kill it. We will generally replace a bag that has become mouldy if the mycelium is too badly affected to recover. Most often the mould has entered after the bag was made, via the air holes. Oftentimes, it's after a person has oversoaked the bag during rehydration.

Our Method: We have a production method that is reliable so we can ensure consistency across many batches. The only variable is the grain spawn used to make the batch (there is one bag of spawn per batch). Issues with spawn would be due to contamination of the spawn and would affect the entire batch. For us, this would be rare as we have a laboratory clean room where the cultures and spawn are made and we have tight protocols to maintain sterility. However, if it does happen this contamination would most likely be mould or bacteria. These are relatively easy to spot, so we would not use the spawn bag for production.

Control Bag: For each batch, we retain a small sample to make a control bag. If you contact us, we can then compare your bag with the control. This gives us better insight into what may be happening, and the advice we can offer to fix problems. It would also alert us to any potential contamination issue affecting the entire batch. Note: We incubate the control bag in our barn. It does not get any special or favourable treatment.

Our Support: We pride ourselves in our ability to work with you in having a successful mushroom grow. This means overcoming any issue you may have with the growing conditions. If we simply replace the bag without overcoming the problem, then we potentially doom the new one to the same fate.

If you need support, please contact us using the live chat feature of the website (or by facebook message). Please include a photo of the bag, including the batch number on the side. Also, if you can, the order number.

4. Mushroom pests, what to look out for

There are only two main mushroom pests to look out for. The Phorid fly and the Sciarid Fly (aka fungus gnat). Both of these flies will lay eggs in the holes of the bags. After the eggs hatch, the larvae roam inside the substrate and quickly devour the mycelium inside. Eventually eating through the stem of the mushroom they emerge as flying adults via tiny pinprick looking holes, out the top.

Less of a problem, unless it's growing outside, are snails and slugs. They seem to seek out mushrooms and devour entire clusters overnight.

Note: Although it is still possible, I have not seen any evidence of rodents, chooks/ducks (or our little pig) showing any interest in eating our mushrooms.

The top two mushroom pests

  1. The phorid fly looks similar to a fruit fly or sandfly. It is often seen around the soil of damp pot plants. Its larvae are tiny white wiggling maggots, Sometimes they are hard to see without a magnifying glass.
  2. The scarid fly has long legs and a slender body so looks more like a mosquito. Its maggots are much larger so generally easier to spot. They are white, plump and often with a blackhead.

If you have the bags inside, these pests are not usually a problem unless you have pot plants already infested, or a problem in the garden outside the window. If you are growing outside you have a high chance of meeting them.

Signs: How to tell if you have them

  1. You may notice the larvae crawling out of the mushrooms after harvest (or inside the bag near the holes). If you put the harvested mushrooms inside a plastic container and in the fridge, the cold will usually drive them out and you will see them in the container.
  2. You may see what looks like pinpricks on the cap. This is where the adult fly has emerged.
  3. The stem of the mushroom will be weak and crumbly (as they tunnel through). The stem may be so weakened that the mushrooms will just fall off and look rotten.
  4. If badly infected (older bag) you may notice the otherwise healthy white mycelium become thin and patchy, signs that it has been eaten.
  5. If slugs the caps will look like something's been eating them

What should I do if I see them?

We use yellow sticky fly traps that you can buy from garden centres or hardware stores. These will catch the adult flies, breaking their breeding cycle. The traps are useful, and they provide a good indicator of having a problem or how big the problem is. If you are inclined to use sprays, use organic ones containing Pyrethrum. These are more for management before you have a problem, as they may not cure a massive infestation.

What if I accidentally eat them?

Firstly, don't panic, they may look gross but are not harmful... to us at least. They have happily been munching on a diet of mushrooms inside an essentially sterile environment. They are very common inside wild foraged mushrooms.  In the future, they may even end up on the plate as a form of future protein.

Further research

Factoid: These last two articles are from PennState University. Pennsylvania has a massive mushroom growing industry, hence very solid research.

Have other problems with your mushroom grow? Here's our article about the two most common issues: https://mycobio.co.nz/knowledge-base/if-it-hasnt-gone-as-expected/

5. I see mould, is that a problem?

It is very unlikely you will get an outbreak of mould. But, mould is perhaps one of the most opportunist and pervasive lifeforms on the planet, so it can happen. However, Shiitake & Oyster mushrooms have had millions of years perfecting the art of dealing with it so are fairly aggressive. If you have an outbreak here's what you can do

  1. Put some tape over any holes directly over the mould. This will deny it oxygen and contain mould spores inside the bag.
  2. Use a marker pen to put an outline of the outbreak. This will more easily indicate if it's growing or receding.
  3. If it looks like it's spreading or the outbreak happens in the first 2 weeks - contact us on the live chat and attach a photo of the mould plus one of the batch numbers on the bag.

Note: For every batch we make (with about 15 mini-farms per batch), We also make a small control bag that we keep in the lab. This way we can monitor what's been sent out. For instance, check how long the batch is taking to pin or if we have a mould problem with the batch (extremely rare). Giving us the batch number allows us to check your mini-farm with the one in the lab.

A note on mould

3. Misting & Humidity

Mushrooms need high humidity when they are growing. So, it's only at this 'fruiting' stage - from pinning to harvest- that you need to care for them. When it's incubating or dormant (between flushes) you do not need to care for it as long as you have it properly hydrated. At that stage all the water it needs is inside the bag.  The easiest way you can keep the humidity high is by misting.

We recommend (at least until you have learned the ropes) putting it inside your shower cubicle (on a plastic stool or somesuch) after you have showered. Leave it fairly wet in there, and to make doubly certain, mist it several times of day as well. This will be the most humid part of the house.

Quick Tips


  1. Rule of thumb: if you have the mushrooms in a spot where you think damp laundry would dry easily, that is not a good spot!
  2. When not to mist: You do not need to mist it UNTIL the baby mushrooms start growing. The water it needs is already inside the bag... unless the substrate has dried out (see post-harvest care for more information).
  3. Be vigilant looking for baby mushroom growth: After you receive the bag, keep a close eye on it because it may start growing at any time. They grow quickly, so you'll need to mist (or put it in the shower cubicle) as soon as you see activity.
  4. The first 8 hours are very important: If it starts during the night and it's in a bad spot, or you fail to get to it in time: it may stall. The Pinks are very susceptible to this. This means they will not bother to grow and will wait till more favourable conditions. See post-harvest care for what to do if this happens, as you will need to clear the air holes.
  5. Learn your unique humidity needs: There is no easy or right answer as to how often to mist. This will be dependent on many variables unique to your environment. However a good rule of thumb, and until you are comfortable with how they are behaving (in other words, your ability in hearing what they are telling you), mist as often as you possibly can. 6 or 8 times a day may not be sufficient for the location you have put it. I have yet to hear from any of our customers who over misting ...but many have failed by underdoing it.
  6. Still uncertain?: err on the side of caution, at least until you have had your first flush and have 'learned the ropes. The best place in the house will be inside your shower cubicle. After you've showered put the mini-farm on a plastic stool inside, and close the door. Leave it wet in there, so don't squeegee out the drops. If you are going out for the day, briefly run the shower on them. Tepid water is best. If you have made them completely wet, make sure they have had time to dry a little before doing it again. Else you may notice they will go a little slimy.
  7. Build a himidicrib. Here's a link on how you can build a simple mini-greenhouse. https://mycobio.co.nz/build-a-humidi-crib/

Little factoid

Are these grown on logs?

We do not grow on logs because it’s a very slow process, with a lower success rate. Instead, we use a mixture of organic pine sawdust, plus some locally sourced wheat and barley (whole grain) for added nutrition.
As the shiitake mycelium colonises the substrate it binds the loose sawdust into a fairly solid block and gains a texture similar to cork.

2. If it's not growing as expected

An important thing to remember, we are dealing with nature. So, it may go as expected even if you followed all the instructions.

Most of our tips are aimed at increasing your understanding of growing mushrooms and managing your mushroom growing environment. In many cases, patience is often the best option, as nature will inevitably kick in (with more favourable spring or autumn-like conditions), but there are things you can still do to encourage it.

Here are the top two problems and what you can do to fix them. Also note, you may experience both of these conditions. This would be indicative that you have not selected a good spot.

1) Pin-set stalling and drying up

2) Dormancy, failing to pin after 4 weeks.

If your grow kit has not started to pin after about 4 weeks it may have gone dormant. This can happen at any time of the year but is more common in summer and the middle of winter. It is caused by a lack of temperature fluctuation.

Generally, the bag will look very well colonised (often very white) as the conditions are favouring the mycelium to grow. It may also develop dark brown patches, which can be a sign that it's starting to get stressed. The mushrooms are simply waiting for a wider variation in temperature, especially fluctuation in daytime/nighttime temperature. So, being inside a well-insulated house it may not feel the fluctuation.

It's usually a simple fix, just leave it outside for a few days.


Do they grow at any time of year, or in my location?

If you are growing inside... Yes, these mushrooms grow any time of year and everywhere in NZ. In nature, mushrooms grow in spring and autumn conditions, due to rain but still warm weather, driving up humidity. Inside our home, we generally simulate spring-like temperatures, so the mushrooms respond, as long as humidity is managed.

However, there are a few things to know.

Mushroom growing tips by season

Sping and Autumn: Generally this is the best time of year. In some cases, for people living in an ideal location, not much care is required at all. Often, frequent rain plus warmer steps provide good humidity, plus overnight lows provide adequate temperature variation (in a not so well insulated house at least).

Summer: Is generally good, especially after rain. However during periods of "good weather," they may go dormant as they are waiting for a temperature fluctuation. This may be more of a problem in well-insulated homes. Also, air conditioning is designed to remove humidity. This will dry mushrooms out and "stall" them. Also be mindful of drafts from open windows as the air may be dry.

Winter: Most of NZ has relatively mild winters (more similar to spring and autumn in northern latitudes of Europe, North America and Asia. So, mushrooms can grow very well. However, heat pumps and other forms of heating will dry the air. So, 'stalling' is more common. Dormancy can also happen, especially if the house is well insulated and you are able to maintain a fairly constant temperature.

Please refer to the 'things not going as expected'.and the Humidity and Misting articles for more information.


Does it grow in the dark?

In nature these mushrooms grow in the deep shade of the forest, so inside light is about right. They are okay with a little sun, but be careful not to let this dry them out. Interestingly the UV in sunlight will help them produce victim D in a similar way our body does.

However, they do not need light to grow (as a plant does) so they are okay without light.

Little Factoid

The myth of mushrooms growing in the dark goes back to when the French began the mass cultivation of mushrooms in caves. This was because the cave had a constant temp and high humidity, rather than due to a lack of light. Not ironically they are called 'field' mushrooms for a reason, because they grow in open fields ...and in full sunlight! These mushrooms will in fact kill trees to create pasture for grazing animals (think of a clearing in a forest). The mushrooms then wait for a fresh pile of dung, which provides the mushroom with the humidity and warmth for the fruit body to grow, plus the substrate for the spores to later colonise. These types of mushrooms have an association with grasses and are one of the many important organisations that create soil.

This is also why growers of field mushrooms (like Buttons) are often in trouble for making a stink. They are often located close to poultry farms and collect the chicken poo (composted down) to make the substrate. Note: Our mushrooms grow on trees, so we use clean sa dust, so there is no poo or associated smell with our mushrooms.

How long will it last?

With minimal care, a mini-farm should last about 6-8 weeks and in that time give 3 flushes (harvests). But, with a bit more care basically just soaking in a bucket of water, it could last over 6 months and give many flushes. Its yield, however, will diminish the older it gets. We also provide tips and advice on how you can keep the mushroom grow kit producing for longer.

We have had feedback from many customers that have kept there's producing for more than 10 months.

1.4. Post harvest care

We sincerely hope you've had a bumper harvest from your first flush and looking forward to the second - which should be 2-3 weeks after the first. There are now a couple of things required to get it ready for its second, or subsequent flush. You may also need to do this if you had a failed flush and all your mushrooms stalled. In which case, we call this re-setting the bag.

1. Clear the air holes

Run your hand over the outside of the bag to clear the holes of any debris and nubby bits like pin-sets that failed to grow, or stem stumps from harvested mushrooms. We want these airholes clear so it gets plenty of fresh air and space to grow next time.

2. Check if it needs a drink

Weigh the bag and compare its new weight to its original weight. The difference is the water loss.

3. The Rehydration

Once it's lost about 70% of its water it's time for it to take a dunk. Generally, this should not be needed until after the 3rd flush (or possibly its 2nd if you have it in a dry location). Do this by...

Note: Do not oversoak. This is one of the few things that will harm the mycelium and may cause mould. 

Now you know everything you need, in order to be successful for subsequent flushes.If you do a good job in caring for it, it should reward you for many months to come. We have had customers give us feedback that theirs are still producing after 10 months. However, its yield will diminish as nutrition is depleted. You may want to experiment by adding some diluted liquid fertiliser to it. Use a metal straw, inserted into strategic spots inside the bag.


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