How to Build A Monotub for Shroom Cultivation

If you're looking to build a monotub for magic mushroom cultivation, you've come to the right place! In this guide, we'll walk you through the steps of creating a successful monotub, from preparing the substrate to harvesting your mushrooms. Building a monotub requires precision and attention to detail, but with the right guidance, you can create an ideal environment for your magic mushrooms to thrive. While there are many ways to prep a monotub, these instructions should provide a good framework for anyone just starting out. 

This article is for educational purposes only, and cultivation should only be performed where growing Psilocybin Mushrooms is legal. Please contact your local authorities to verify the laws in your area. 

For those interested in microscopy, check out our extensive offering of magic mushroom spore syringes while supplies last. Let's dive back in. 


Why Use A Monotub? (Important) 

Monotubs are a crucial component of the mushroom fruiting stage because they provide an ideal environment for mycelium growth and fruiting body development. Mycelium is the vegetative part of the mushroom fungus that colonizes the substrate, and it requires a specific set of environmental conditions to start developing a mushroom.

Monotubs are designed to maintain high humidity levels, optimal temperature, and proper air circulation, all of which are necessary for fulfilling those environmental requirements. The tubs also provide a controlled environment that helps to prevent contamination from other microorganisms, ensuring a healthy growth cycle.

If you plan to get serious about mycology, understanding monotubs is a must! 



Step 1: Choose Your Container

The first step in building a monotub for magic mushroom cultivation is to choose your container. A plastic storage tub with a lid is ideal for this purpose. Make sure that the container is large enough to accommodate the amount of substrate you'll be using. Alternatively, you can save a bit of effort by buying a monotub for Max Yield Bins or Boomer Shroomer. We are not affiliated with those companies. Rather, we just want you to have a successful experience. 

Multiple MonoTubs

Step 2: Prepare Your Tub

1. Make Holes: The next step is to prepare your monotub. Using a drill or hot nail, make several small holes in the sides of the container to allow for air exchange. We'd recommend holes with a 2-3 inch diameter, but as long air can circulate reasonably well in & out of your tub, you don't need to follow those measurements exactly. If you can't drill large holes, you can compensate by drilling a higher volume of small holes.

2. Fill holes with polyfill: You should then proceed to fill the holes with polyfill, a cotton-like material that allows for air exchange while reducing the amount of contaminants flowing in and out. If you don't have polyfill, you can get creative with a number of other materials like cotton balls, filters, the list goes on.

3. Close Lid: You'll also want to close the lid on top. Without a lid, the mycelium is completely exposed which increases the risk of it drying out or becoming contaminated. 

4. Add Liner: Before you perform the next steps, we'd recommend adding an opaque liner on the bottom of your tub, such as a black trash bag, to prevent mushrooms from pinning on the sides or bottom. 

Monotub with pollyfill

Step 3: Add Necessary Contents to the Monotub

Once the mycelium has fully colonized your grain and you have grain spawn, you'll need to transfer it to the monotub and introduce it to your bulk substrate. However, the monotub must be pre-prepped with some other contents before you introduce mycelium. In this example, we'll be discussing bulk substrates: 

Setting your tub up with a "bulk substrate": In this case, the best "bulk substrate" to use is a pasteurized mix of Vermiculite, Coco Coir, and Gypsum. Many people may want to use manure, but the list is endless for ways to concoct a bulk substrate. Measurements will vary based on your set up, but proportions generally stay the same. 1/3 of your bulk substrate should be vermiculite, 1/2 should be Coco Coir, and 1/6 should be Gypsum powder. You MUST pasteurize substrate to kill most but not all competing microbes within it before use. After letting your mixture cool, you can add a 2-4 inch layer of it on the floor of your tub. Then, crumble up and add some grain spawn on top of the bulk substrate and mix. Your mycelium will colonize the rest of the substrate over the next few days as it gets ready to fruit. 

Monotub with Vermaculite

Step 4: Maintaining the Monotub For Fruiting

At this point in the process, you need to focus on maintaining your tub and getting the right environmental conditions down for the mushrooms to properly grow. The environment inside the container should be kept humid and well-ventilated. Mist the walls and lid of the container using a spray bottle with sterile water, and then ensure that the container is receiving fresh air exchange by fanning it for 30 seconds. The goal is to remove the Carbon Dioxide and fill the tub with fresh oxygen. Repeat this process several times a day to ensure that the substrate remains moist but not saturated, and that air is circulating but not gushing in & out. Depending on the type of mushroom you grow, like Penis Envy, you'll also need to consider levels of lighting. Most mushrooms do well with indirect sunlight, but some may benefit from set-up lighting. In summary:

  1. Mist the walls & lid periodically
  2. Pay close attention to air exchange. Don't over-fan or under-circulate your tub, but allow for thorough air exchange. 
  3. Keep the tub in a warm, moist area, free of contaminants 
  4. Provide indirect sunlight or set up lights
  5. Keep everything as sterile as possible


My first ever monotub.
by u/klaymenofneverhood in shroomers


Step 5: Harvest the Magic Mushrooms 

It is important to mention what you can expect to see from your tub to know if you have set it up properly. After a few days, you should start to see pins forming on the surface of the substrate. These are the beginnings of the mushrooms. Once the mushrooms have grown to the desired size, gently twist and pull them off the substrate. Make sure to wear gloves or wash your hands thoroughly before handling the mushrooms.

If you cut the mushrooms, the bases will be left exposed, becoming vectors of contamination. Contamination can threaten your whole tub, so be extra careful.

In conclusion, building a monotub for magic mushroom cultivation requires careful preparation and maintenance. Following these steps will help you create an ideal environment for your mushrooms to grow and produce a bountiful harvest.

Disclaimer: We offer Psilocybin mushroom spores intended for microscopy and taxonomy purposes only. Images & Text provided are for informational and educational reference only and originate from cultivators and labs outside of the USA. Buying magic mushroom spores is legal in the United States. However, cultivation of magic mushrooms, which includes all psilocybin and psilocin containing mushroom species, is illegal in many countries, including the United States. Please check your local regulations to ensure that you are following the law properly.