DIY Mushroom Monotub tek - Monotub Mushroom Bulk Grow Guide

 DIY Mushroom Monotub tek – Design, Build and Growing Guide

Our DIY Monotub tek Build & Grow Guide will cover step by step the simple design, the construction and finally growing with what might be the easiest mushroom monotub tek ever made.

mushroom-monotub-tek-fruiting-gourmet-shrooms.jpgpsilocybe-cubensis-golden-teacher-strain-growing-in-diy-monotub.jpgThere are several techniques for growing mushrooms using monotubs, and new methods continue to be added every day.

Commonly associated with the cultivation of Magic Mushrooms or Shrooms, monotub growing is particularly well suited to Cubensis and select other Psilocybe species.


Any mushrooms that are suited for manure based substrate can be grown using this technique. By changing the bulk substrate to wood based from manure based, you could then grow oyster mushrooms from the Namekos and Pleurotus family.


Items needed for this technique

  1. Latex gloves

  2. Gorilla tape or any other suitable alternative

  3. A dark color plastic tray with a lid large enough to easily contain all of the growing substrate

  4. A spore or culture syringe

  5. A mushroom grow bag

  6. A fully colonized grain spawn You don't need the syringe and sterilized grow bag if you already have this

  7. A hand-drill with a two-inch hole saw

  8. A pair of spray bottles for water and alcohol, - We advise 70%

  9. Poly-fil, tyvek, micropore tape or cotton balls to cover all the holes you drill

  10. Bulk substrate. This could be hardwood based wood chips or manure-based substrate. It depends on the species of mushroom


Optional items/upgrades - Not required

  1. An LED light bar

  2. A Cycle timer

  3. A fan

  4. A humidity regulator

  5. A humidifier with a flexible hose - Ultrasonic Humidifier works best



Step 1: Prepare the mushroom grain spawn

Grain spawn is any grain that has been hydrated, sterilized and then colonized by the mushroom mycelium.


You can buy mushroom grain spawn or you can make your own. Rye is most common but nearly any cereal grain works well.

If you are growing a popular edible mushroom variety like Oysters, Chicken of the Woods, Agaricus, Shiitake, ect, you can purchase the already colonized grain spawn. The substrate used in the monotub may need to be changed depending on the species of mushroom being grown.

For magic strains, exotic varieties and uncommon species of mushroom it may be difficult to find colonized grain spawn for sale and it will likely be necessary to make your own spawn and inoculate it from spore syringe.


Step 1: How to make sterilized grain spawn

Make or purchase a supply of sterilized all in one mushroom grow bags, or a sterilized grain bag. The bags will contain hydrated and sterilized millet, rye or another grain that has been prepped and made ready for mycelium to germinate.


Here is our detailed guide to spore syringe inoculation of grain. Basically, begin by ensuring there are no micro cracks in the bag, then clean the surface of sterilized grain bag and inject about 2.5ml of culture syringe through the injection point. Do this in a very clean location. It is important to create a very clean environment for this as the process is highly delicate. It's best to sterilize your hands, the inoculation surface, the injection bag and the syringe needle. prep-materials-for-inoculation.jpeg Rubbing alcohol will work for sterilization. Wear a pair of latex gloves throughout the process. Need more info about spores? The in depth look at what the mushroom sporeworks is and does.


Let your sterilized grain bag become colonized in a cool and dark location. Avoid direct sunlight on the mycelium if possible. Aim for a steady temperature of about 75 deg. f. It’s best not drop below 55⁰F and it shouldn’t rise above 85⁰F. The warmer it is within this range the faster growth will be. After a few days you’ll start to see white mycelium growing on the grain. The white mycelium will expand outward from the injection point. Let it grow to about 75%, then break up the colonized grain without opening the bag. Mix the colonized grain into the grain that hasn’t been colonized. This will hasten the colonization process.

Once the bag is full of white mycelium, mycelium-fully-colonized-and-ready-to-transfer-to-monotub.jpeg the mushroom spawn is ready to expand. This could take a few weeks to a few months depending on temps, grain choice and the species of culture used.


Step 2: How to Make Bulk Substrate

The contents of your bulk substrate depend on the type of mushroom that you want to grow in your monotub. For our guide we'll assume the most popular species of manure loving magic mushroom, Psilocybe Cubensis and the most potent of the Cubensis strains: The Penis Envy Mushroom


You can use ready made manure substrate that has already been cooked and sterilized. horse-manure-bulk-mushroom-substrate-best-monotub-tek-substrate.jpg With ready made manure substrate, you do not need to gather ingredients and spend time mixing them together.

To make your own manure substrate it’s easier to start with an easy combo of 50% horse poo and 50% coco coir. You can get horse manure from stables and farms if any are nearby to you. Horse manure that has aged outdoors or composted for at least 6 months is the best. You can get coco coir from gardening or hydroponic shops.

Mix the coco coir, and the horse manure together and get the mixture hydrated to field capacity, or when 3 drops fall from a lightly squeezed handful. Take a handful of the substrate and squeeze it. You should be able to get at least two drops of water. Any more than four means that the mixture is over hydrated. Add a small amount of coco coir to absorb the excess. If a handful of the mixture can’t yield one or two drops of water, then it is under hydrated. Slowly add a small amount of hot water, mixing and testing often.

Bulk substrate can be pasteurized by steaming or cooking in an oven. To steam it, put the substrate in autoclave-able filter patch bags and steam it in a pressure cooker to about 180⁰F. Alternately you could preheat the oven to 170⁰F and cook the substrate using baking pans. Wrap the baking pans with a tinfoil cover and cook for about two and a half hours.

Sterilizing your substrate requires an autoclave or pressure cooker.

Let the substrate cool down before using it. Once cooled spawning should take place immediately.


Step 3: Prepare the Monotub

There are several methods and designs for making a monotub. All of them will grow mushrooms.


The most common container used is the large plastic Rubbermaid or Tupperware containers. Mushrooms are phototrophic, or sensitive to light when growing, and they will lean towards the direction of the light. blogsize.cubensis-leaning-toward-light.jpg In an equally dimly lit area each mushroom might grow it's own direction.


The lid of the bin should allow light in so the mushrooms grow upward. Mushrooms that grow towards the bottom or side are difficult to harvest and will waste energy and the nutrients provided by the substrate. Be sure to select a container is dark in color and includes a see thru lid. Alternately you can simply add a contractor trash bag to a clear container with some tape. This will let the mushrooms grow as they should and make them easily to harvest.


You need some holes in the bin for it to breathe. This is where the drill with a two-inch saw bit comes in handy. Use the drill to create holes around the upper half of the bin. We advise about eight inches of space between the holes in the upper half of the bin, but evenly spaced or randomly placed holes both function equally well. The holes should be above the highest substrate level that will be in the bin. Many other tools can be used to make holes in the bin if you don’t have a drill.

Fill up the holes you have drilled with polyfill or cover with Tyvek. Either will stop particles in the air from entering the substrate while ensuring that the substrate can exchange air as needed. Use heavy strength tape to seal the polyfill so it won’t pop out.

Now, the monotub is ready!


Step 4: Clean the working area, the bulk substrate bags and the Monotub

This step is very important so you the whole process needs to be done carefully. Ensure that you are in a very clean room. Vacuum the room and wait for some time, so that the particles in the air can settle. Close windows and doors. The goal is to avoid contamination entering through any medium. Use some of the rubbing alcohol in a spray bottle to sterilize the entire area and the monotub. Spray your hands, working surface, scissors and any other tool you’ll be using. Spray the outside of the bulk substrate bag and the spawn bag.


Step 5: Mixing colonized spawn with new substrate

fully-colonized-substrate-ready-to-be-spawned-to-bulk-substrate-inside-monotub.jpegfully-colonized-grow-bag-mycelium-being-broken-apart-and-mixed-into-bulk-substrate.jpegThe amount of spawn and bulk substrate to use depends on the design of the monotub built. The substrate should be three to five inches deep in the tub. A good rule of thumb is 1lb of spawn will be able to inoculate 4-5 lb of new substrate.

Ensure that the bulk substrate has adequate water by repeating the test you carried out earlier to check the moisture content of the substrate. If a handful of substrate can’t yield two drops of water, add a little sterilized water to the mixture as you fill the monotub.

Break up the colonized grain and the manure substrate in the monotub and mix them together well. Then lightly press the surface of the substrate down with the flat of your hands to ensure contact between the colonized grains and the new manure substrate.

Cover the monotub bulk bin and keep it out of direct sunlight in a place that is a bit warm, aim for about 75-80 deg. f. for fast expansion.


Step 6: Wait for the mycelium to fully colonize the Monotub substrate

Soon when looking thru the sides of the bin you’ll start to notice white spots of mycelium expanding from every point of grain. Once the white mycelium covers the entire surface of the substrate small droplets will start to pop out. This is a good sign of fast colonization and proper hydration.

Begin the check for hyphal knots, or primordia, once the monotub is fully colonized. cubensis-primordia-starting-to-grow-from-cased-bulk-substrate-monotub.jpgSoon those will become pinning mushrooms and rapidly grow to mature harvest ready fruits. Mushroom pins grow vertically from the surface of the bulk substrate after starting as small hyphal knots of white mycelium. 


For manure grown species the monotub substrate will take two or three weeks to colonize. For hardwood, the colonization rate varies by species.


Step 7: Harvest the Mushrooms in the Monotub

Once you begin to notice hyphae pins or knots it’s time to remove the lid from the bin and begin to spray the tub with water a few times each day. Open the lid so that air can be exchanged inside the monotub. Ambient light is ample for the mushrooms to grow in the right direction.

Wait till the mushrooms have grown to the size you want them, then harvest. Most Psilocybe Cubensis strains are ready to harvest just before the caps flatten out, or as the thin membrane on the underside of the cap starts to tear. psilocybe-cubensis-golden-teacher-strain-growing-in-diy-monotub.jpg


Want the bulk of a mushroom monotub without the monotub construction? Everyone uses this all included Monotub Tek Grow kit, it just needs spores to begin your monotub tek mushroom growing adventure.


Questions? We’re here to help you every step of the way.