FAQ: Frequently Asked Questions
If you’re just starting out growing mushrooms, you’ll almost certainly have a head full of questions. The most frequently asked questions can of course be googled and you may well find your answers quickly and easily – or you may find a dozen different answers to the same question. In many cases, all the answers will be correct (to one degree or another) as growers eventually develop ways of working and techniques that work for them and the particular mushrooms they grow.
We’ll try answering as many of the most frequently asked questions below – for convenience we’ve tried categorising questions into logical groups.
General Questions
These are frequently asked questions we couldn’t find a category for..
Absolutely yes.
There are many different levels, different ways to be involved with growing mushrooms and at the most basic level – buying a simple ready-to-go grow bag which requires you to do little more than find a shady spot for your grow bag and spray it with water as it grows – it barely involves any serious effort and absolutely no special equipment.
If you want to be involved in more aspects of mushroom cultivation, you might want to buy various bits of equipment to help you. If you want to be involved with all aspects of mushroom cultivation from developing spores into mycelium onwards, you might want to have a room you can reserve for that purpose and you’ll need to buy more equipment, but there’s very little that can’t be done at home.
Probably the most common mistakes relate to things that are mentioned throughout this website:
Sterile working – it isn’t optional. Grabbing a cloth out of the sink and wiping surfaces down might do in a general sense, but not when you’re working with mushrooms. Having an OCD cleaning obsession will not hurt you even a little bit!
Rushing – mushrooms and mycelium hate impatient people. Everything needs to be done carefully, things like allowing things to cool down can’t be forced. Opening a pressure cooker too soon can suck contaminated air in, inoculating spawn before it has cooled down will only cook your mycelium, and so on. Take your time and be patient.
Remember value for money – cheap is rarely the best option. Example; there are countless cheap mushroom bags available for sale all over the internet. They were shipped here from China yet still cost a fraction of what high quality bags do, and there’s a reason for that. Shoddy construction that will see you split bags without too much trouble, filters of an unknown quality and so on. If you need cheap, fair enough, but good quality equipment and supplies will last longer, provide better results and cost less in the longer term. The same applies to things like laminar flow hoods, incubation chambers for petri dishes and liquid culture, decent impulse sealers for bags and so on. Even if growing mushrooms is a hobby, investing wisely always pays.
Ignoring environment suitability – read up on the conditions your chose mushroom needs in order to grow properly. Provide those conditions – whether that’s temperature, amounts of light, humidity levels and air exchange requirements. A bit like having a pet, Great Danes don’t generally eat rabbit food (yes, they’re about as smart as a dandelion and doubtless one or two will give it a go, but still….) and amazonian snakes rarely survive long if kept in an unheated garden shed.
Not being methodical – find a technique and method of doing everything. Write it down if you’re liable to forget, and follow it. If you make a mistake you can backtrack and work out what it was, and avoid it in future. Label everything you do – when each batch of agar was made, and with what. When your substrate was prepared, what liquid culture you incoculate with and the date (so you can learn how quickly results should appear. And so on.
All sellers have their own way to describe what are loosely termed mushroom ‘grow bags’. Reading the description fully is important as different sellers will describe the same thing in different ways.
In essence, this is what you will find on sale online:
‘Ready to go’ grow bags. These are usually supplied by businesses which sell mushrooms as opposed to equipment for mushroom growing. They’ll be described as being already ‘inoculated’ or ‘colonised’ or ‘ready to fruit’. These bags will already have been inoculated with liquid culture or spores (think of this as having the seeds already planted and germinated) and will generally be supplied as a special polythene bag encased in a box which you partly open. Apart from spraying the contemts of the box with water regularly, there’s little you need to do with these boxes. ‘Ready to fruit’ is probably the phrase to look for, as well as being asked at the time of ordering what type of mushroom box you want to order.
‘All in one’ and ‘Grow bags’. These are normally bags which contain sterilised grain and substrate (a bit like soil) to which you need to add liquid culture or spores. One or two we’ve seen also include your choice of liquid culture syringe, but not many. These bags generally don’t contain or include liquid culture or spores and are in effect a blank canvas. You then need to find and buy the liquid culture which has to be injected into the grain to kick-start the growing process. The bags will also have different substrates – which will suit different types of mushrooms. It’s worth asking the seller which mushrooms the bags are suited for if you don’t already know.
You should also check that the contents are already sterilised, as we’ve also seen some sellers who supply ‘kits’ that haven’t already been prepared – some substrates will need to be sterilised, some will need to be pasteurised. If you don’t know how to do these things, go for a kit that is ready to go.
Despite what you saw in ‘The Last of Us’, Cordyceps Sinensis can’t infect humands and can’t even be grown at home, so any ideas you had of infecting unpopular neighbours aren’t going to work.
Frequently asked Questions – Mushroom Substrates
Mushroom spawn is a substance that has been inoculated with mushroom spores or liquid culture to serve as food and home for mycelium to grow in, prior to developing into mushrooms. It can be explained in a much more scientific manner, but that’s the essence of it.
Most of what you find online will refer to ‘grain spawn’ and grain spawn will relate to the grain (such as rye, wheat and so on) which has been injected with either spores or liquid culture to begin the mushroom growth cycle by developing mycelium. It can also be used in a generic way to describe the grain itself – for example when talking about what grain should be used in the process.
Mushroom spawn can be a multitude of materials and before deciding on which you want to use, you need to read up on the type of mushrooms you want to grow and learn what materials they like best.
That said, and speaking in general, many growers swear by rye grain (can also be called rye berries). Other popular choices are wheat, millet (cheaply available and often supplied as a bird food), brown rice and some even use popcorn! Depending on mushroom types you can also use straw, rice flour, cardboard, logs, hardwood sawdust and hardwood wood chips. Some will be ineffective for the mushrooms you want to grow, so read up on your chosen mushroom type first!
As per questions about mushroom spawn, the best substrate to use with your spawn material depends on the type of mushroom you want to grow – and then depends on the type of spawn you choose to use. Different growers will have their own preferred substrate, which is invariably a mix of different materials. The thing to remember is that the majority of mushroom species can be divided into ‘wood-loving’ and ‘maure-loving’. Most mushrooms grow in the wild on dead wood, straw, other decaying organic material or manure. This has a bearing on which substrates and spawn to use.
A quick look online will throw up countless references to CVG substrates. It seems the most popular choice, but the apparent popularity of these references is inflated by the number of people growing magic mushrooms – as CVG substrates are considered to be among the best for that purpose. CVG is also suitable for growing button or portobello muchrooms when paired with a grain spawn.
Mushrooms such as Oyster (in particular), Lion’s Mane and Enoki generally do well in a 50:50 mix of hardwood pellets and soy hulls (some will add small amounts of bran to further supplement the mix). Many wood-loving species will grow well on a hardwood sawdust based substrate and there are many different recipes out there, generally supplemented according to your target mushroom species.
It all boils down to you reading up on your chosen type of mushroom and what they grow best in.
CVG substrate is a mushroom substrate which consists of a mix of Coco Coir, Vermiculite and Gypsum. Although it can also be used for button mushrooms, it is most widely used as a fruiting medium for growing psilocybin mushrooms.
The simple answer is ‘Yes, it should’…. but you probably want to know which one is better! In that case the answer depends on what you want it for:
Making Grow Bags
If you’re preparing grow bags including grain, STERILISE, full stop. In this case, you put your substrate and grain into a mushroom bag together, sterilise it in your pressure cooker and seal it once cooled down. That’s how that should be done.
Bulk substrate for monotubs (etc)
When you’re making substrate to add to colonised grain spawn, you can choose which path to follow.
Pasteurisation
Many growers will say that CVG (coco coir, vermiculite and gypsum) only needs to be pasteurised, and this is correct. Many successful home growers will tell you that they follow a simple ‘bucket tek’ (a silly name that means use a bucket). You’ll learn that everything mushroom-related has to be a ‘tek’ as this makes it sound very complicated….
The process followed is rather unscientific, in truth, but effective enough. Mix your coir (break up any lumps in advance) and vermiculite, add the gypsum to boiling water (mix it well to avoid silt in the container) then pour it over your coir/vermiculite. Stir to mix thoroughly, firstly to ensure the mix is evenly hydrated and also to make sure the vermiculite is evenly distributed, then leave in your sealed bucket for 2-4 hours (depending on who you ask). You can optionally wrap the bucket in towels to try to maintain the temperature for as long as possible. As an alternative, you can do the above as directed, then place your sealed bucket inside another bucket (can be open-topped) which contains hot water (around 70C) , which will keep your substrate at a higher temperature for longer. The most important part of the whole process is to make sure you use the right amount of water as substrate that’s too wet or too dry is bad news.
It must be said that this process works almost all the time and there is no specific reason to use a sterilisation process for CVG.
Sterilisation
The above will tell you sterilisation isn’t actually necessary. Some will also say that some gourmet mushrooms prefer pasteurised substrates over sterilised – that may or may not be a fact but we’re doubtful. In any case, none of this means you can’t or shouldn’t sterilise. It’s your choice. If you’ve had past issues with contamination and want to be on the safe side, sterilising your CVG is a perfectly good option.
There are many types of mushroom which grow best on a wood-based substrate. Most wood-based substrates are made of either hardwood pellets or hardwood sawdust (generally supplied as compressed pellets). Very few mushrooms like softwood. It’s worth reading up on the specific type of mushroom you want to grow, as some are quite picky about what types of wood they’ll grow (well) on. Some prefer oak and so on..
Frequently asked Questions – Sterile Working
If you’ve read anything about growing mushrooms you’ll have come across many references to sterile working, both general and specific. Here we’ll try to cover the most frequently asked questions.
A laminar flow hood is a relatively simple construction; it’s a box which houses a fan, either a squirrel-cage type blower on top of the box or an axial fan at the rear. The fan draws air out of the room and blows it into the box. The air is then forced to exit at the front onto your workspace through an air filter – a HEPA H14 is the recommended type. The HEPA filter removes particles and potential contaminants from the air down to 0.02 micron in size and so washes your working area in clean and non-turbulent air.
To provide clean air, the flow hood needs a HEPA filter, ideally type H14. H13 can be used but isn’t as effective – and as filters are used they become less effective, so it’s best to start with a more effective filter in the first place to allow for this.
Whatever type of flow hood you find, check its claimed performance and specs before you buy. If it doesn’t mention filter type (many say little more than ‘filter’ or sometimes ‘hepa’) ask. If it doesn’t specify air speed, check. If the seller can’t tell you, they have no genuine idea if what they are selling is suitable. If they quote an airflow speed, as how it was measured. The kind of digital anemometer 9wind meter) you find on amazon is not suitable for measurements as they’re notoriously inaccurate, particularly for low wind speeds and 100 feet/minute is only about 1.1mph.
Sites like Amazon are flooded with countless small flow hoods, sometimes so small you wonder if they were made for a child’s hands. You’ll find the same photos used over and over again with numerous “brand” names. These cheap imports from China carefully avoid mentioning filter types, airspeed and anything else you might want to know. Generally, we’d say run like hell. Even the sales blurb only says they’re for working on mobile phones.
Genuine scientific hoods made for lab work will cost north of £1000 new, but you can find custom-made laminar flow hoods made by mushroom growers (we make our own too). The smallest ones are generally 12″ x 12″, but in reality most work requires a larger hood/filter of at least 24″ wide and ideally the same height. A 24″ x 24″ laminar flow hood will typically cost anywhere from £600-£700 depending on the filter and fan type used (H13 filters are not quite as effective but are a bit cheaper). Depending on what you want to do, a larger hood, perhaps 36″ x 24″ would be more suitable. If you’re unsure, find a table top and lay out a reasonable number of containers, petri dishes, slants or whatever you expect to work on. Don’t stack things behind each other as they are blocking the airflow. Now work out how much actual working space you have, or need. It won’t be 12″ wide……
A still air box is a way home growers can get around not having a laminar flow hood but still have a fair chance of reducing the risk of contamination when working with spores, liquid cultures, agar and other related tasks. In essence, a still air box is a transparent plastic storage tub (generally used upside down with the lid attached) with holes cut into the sides to allow you to put your hands inside it and do work inside the box.
The purpose of a still air box is to provide a workspace inside which the air is still – not moving at all or very much. If air isn’t moving, the risk of airborne contamination landing on your work is reduced.
You’ll usually find two different types available:
Basic (often DIY) still air boxes will have two armholes cut into them. That’s about it.
Glove boxes, or sealed (still can be DIY) still air boxes will have two armholes cut into them, around which ports have been attached which hold long-sleeved gloves. The idea is that after loading your still air box (and allowing the air to settle inside) you then put your arms into the gloves and work on your materials without outside air being able to enter. This type of box should offer much higher levels of protection than the basic type.
In relative terms and provided care is taken in how they are made and used, still air boxes will reduce the risk of contamination landing on whatever materials you are working on. Some growers have used still air boxes with excellent results and swear by them.
Effectiveness is down to you and your working/sterile techniques but, all things being equal, sealed glove boxes can be a little more effective than basic unsealed boxes (with just armholes cut into them). Regardless of which type, the insides and all the items you work with must be properly cleaned…
Unsealed still air boxes: These have armholes cut into the side of the still air box. The holes need to be large enough for you to get your arms inside and move sufficiently while working. If the holes are too big they allow air to enter even with your arms inside them. If they are too small they may prevent comfortable working and as you squeeze your arms in or pull them out, they will create an opposite airflow as you move your arms – potentially sucking air in every time you move your arms in an outward direction. As long as they are used with care, still air boxes can provide a safe workspace for working with agar, inoculations and so on, always assuming your sterile techniques are good.
Sealed Glove Boxes; these have similar holes cut into them but the holes have ports attached to them which clamp long-sleeved gloves in place. When using the box you push your arms into the gloves and can work without the risk of outside air being blown or sucked in and out of the box. Upgraded glove boxes will have a small air filter attached over another hole in the box to allow for filtered air to move in and out of the box, balancing air pressure changes as you push your arms inside the box. All being equal, these can be more effective than unsealed basic still air boxes, assuming your sterile techniques are good.
The best way to clean work surfaces and many items you work with, 70% Isopropyl Alcohol and (large) Alcohol wipes are your friends. Simple cleaning with soap and water is always a good idea first, to get rid of as much as possible from surfaces, but it is the alcohol that will do the job properly. Although you can 90% Isopropyl Alcohol, 70% Alcohol is, oddly enough, more effective at killing contaminants. There is an explanation as to why and Google will find it for you, but all you need to know is 70% alcohol is best.
The simple answer is yes you can. Sterilisation occurs at 15psi, just the same as you sterilise substrates and so on, although depending on the items, 15-30 minutes is usually all that’s needed. Most items need to be wrapped in tinfoil before putting them into the pressure cooker; firstly to keep them safe, secondly to keep as much water off them as possible and finally to allow you to take them out afterwards without exposing them to unsterile air. Pressure cooking at 15psi is basically ‘autoclaving’ items. Autoclavable (able to be sterilised at 120c or higher temperature) is a term you need to be familiar with.
Beware:
Not everything can be sterilised. Plastic petri dishes, for example. Some can be autoclaved (pressure sterilised) and some will turn into molten plastic sludge which will ruin your pressure cooker. Some cheaper types of glass can’t be autoclaved either. They can shatter. No container should be closed tight when sterilising – it can cause them to explode with pressure – and instead lids on things like mason jars should be only about 75-80% tight, with tinfoil wrapped over them to protect them.