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Monotub Tek or Sterilized Mushroom Grow Bags: Which Technique Grows Better Mushrooms?

Posted by J&K at APN on 2020 Oct 7th

 Monotub Tek or Sterilized Mushroom Grow Bags: Which Technique Grows Better Mushrooms?

Mushrooms are one of the many wonders of nature. They are incredibly versatile in their use – they can become healers, a delicious meal, or even a source of pleasure. Did you know that they are as interesting in life as they are in their birth?

Mushrooms need highly controlled environmental conditions to grow. Growers have worked hard to develop multiple methods of growing mushrooms and over the decades, they have perfected them.

The two most popular mushroom-growing methods that exist today are Monotub Tek and Sterilized Mushroom Grow Bags. This article will help you understand, compare, and contrast the two processes and decide if one is better than the other.

Growing Mushrooms Using Monotub Tek

Every mushroom grower may make their own improvements to this growing method, but today, we will discuss only the basic setup technique called Monotub Tek.

What is Monotub Tek?

The name is of the technique is self-explanatory. A monotub is a sizeable plastic tub with holes for air circulation. This is the fruiting chamber used for growing mushrooms. Tek is just a shorter form of “technique.”

The origins of the technique come from the hallucinogenic mushroom growers. The varieties of these magic mushrooms showed excellent yield in horse manure. Today, horse manure is the most widely used mushroom substrate while using Monotub Tek. Other popular mushroom substrates include woodchips, straw, and grains, among many others.

This technique enables them to achieve sizeable yields that are far greater than those using an all-in-one mushroom grow bag. What’s more, Monotub Tek does not require them to make huge investments into building a mushroom grow room. Naturally, Monotub Tek has become a rage among small-time professional mushroom farmers who are starting out.

This technique is commonly used to grow Psilocybe Cubensis, Porcini mushrooms, Morel Mushrooms, White Button mushrooms, Cremini mushrooms and Oyster mushrooms, among others.

What You Need?

There are many ways to assemble a monotub. Here is a brief on the fundamental concept of Monotub Tek.

  • Grain Spawn: It is essentially mushroom seed. It is made out of sterilized grain that the mushroom mycelium has completely colonized with mushroom mycelium.
  • Large and Transparent Plastic Tub With A Lid: This is the monotub from which the technique gets its name.
  • Black Spray Paint: The outside bottom of the tub is painted to keep the light out. It prevents the mushrooms from growing at the bottom or at the sides of the tub, which would otherwise be difficult to harvest.
  • Mushroom substrate: The choice of mushroom substrate depends on the mushroom variety
  • Drill or Scissors: To make holes for air circulation
  • Polyester Fiber Fill: To control the airflow
  • Heavy-Duty Duct Tape: To cover the air holes

For a detailed walk-thru on how to build your own Monotub mushroom growing setup look here: Monotub Tek Bulk Mushroom Grow * How-to DIY

How It Works

  • Cut holes in the tub and cover them up with non-breathable tape. These holes are usually at the level of the mushroom substrate for letting the cool air in. Then, there are holes on the top to let the hot air out.
  • The mushroom substrate mixture is mixed with the grain spawn at the bottom of the tub. The mycelium in the grain spawn will start colonizing the mushroom substrate in the mix. This action, combined with the decomposition of the mushroom substrate, generates carbon-dioxide and heat.
  • Hot air will rise up the tub, and the heavier carbon-dioxide stays at the bottom. The tub becomes saturated with the two gases until the mushroom substrate is fully colonized, which leads to primordia growth or pins.
  • At this time, the holes in the monotub are opened to let the cool fresh air rush in. Hydrated Casing is added now if called for.
  • This is the time when the mushroom start growing all over the mushroom substrate.

Growing Mushrooms Using Mushroom grow bags

Growers and enthusiasts use mushroom grow bags in different ways to cultivate gourmet (or even everyday) mushrooms using this method.

What are Mushroom grow bags?

Mushroom bags can be seen as containers that offer a sterilized environment for mushroom growth. The sides of the bag are folded flat and inwards. The gusseted design makes sure that the bag packs compactly and can be opened to reveal a large volume.

The mushroom grow bags are made from a thermoplastic called polypropylene. This material can withstand high temperatures of up to 250oF for long periods, which the bags must endure in a sterilizer. Regular or sub-standard bags would completely melt under such conditions.

Lastly, a mushroom grow bag also has a filter in the front that allows constant airflow. The filter also protects the mushroom culture from the contaminants present in the air.

This refers to the filter on the front of the bag and is one of the most useful aspects of the grow bag. The filter allows for the mushroom cultures inside the bag to receive fresh air, free from contaminants like mold spores and bacteria.

Mushroom grow bags work well for most species and varieties of mushrooms.

What You Need?

  • Polypropylene Bag: This is the grow bag that acts as the container
  • Zip Tie: Zip tie or wire to tie the top of the bag
  • Substrate: As a medium for mushroom growth
  • Rubbing Alcohol: For sterilization
  • Cotton Balls: For cleaning
  • Syringe: For inoculating the mushroom culture
  • Surgical Tape: To cover needle holes

How It Works

  • Put the mushroom substrate in a sterilize-able spawn bag and autoclave at 15 psi. for 90 minutes.
  • Alternatively you can purchase per-sterilized mushroom substrate grow bags. Our BOOM Blocks are perfect for a huge variety of mushrooms and are ready to inoculate with spore syringe.
  • Wipe the needle with rubbing alcohol and fill the needle with spore solution
  • Dip a cotton ball in the rubbing alcohol and wipe the area where you intend to inoculate
  • Inoculate the mushroom substrate and then wipe the needle again with rubbing alcohol
  • Once the mushroom substrate is inoculated, the holes should be covered with surgical tape
  • Place the bag in a humid and cool environment to grow
  • Wait for the formation of primordia and open the top of the bag to allow air transfer.
  • Harvest the mushrooms after 2-4 days. If the substrate is in good condition, it can be reused for another 2 or 3 harvests

Understanding the Differences & Their Consequences

The Container

The Monotub Tek uses a sterilized, clear tub instead of a gusseted bag typically used in the grow bag technique. This is the primary difference between the two methods which introduces the differences in the final result.

As compared to a tub, a bag keeps the mushroom harvest more organized. A grow bag also needs more careful handling. While a tub is self-sufficient, many growers use a sleeve with a grow bag for easy handling. There are also slip-in filters that keep the bags from getting contaminated after the sterilization process.

In addition to this, the clear tubs used in Monotub Tek can be reused. On the other hand, the integrity of a bag and the filter patch progressively weakens after each use. So, growers are better placed if they use new bags after every 1 or 2 harvests to ensure the purity of the harvest. Since the tub is reusable, it makes the Monotub Tek a much more eco-friendly option than the grow bags.

Differences in Sources of Air Flow

The Monotub Tek uses the drilled-in holes as a source of airflow. On the other hand, grow bags rely on filter patches for contaminant-free air supply.

The holes in the tub are centimeters-wide. They are secured with the help of heavy-duty tape and polyester fiberfill. So, if the grower does not properly secure the holes, it can lead to contamination of the mushroom colony in the tub. On the other hand, the filter patch on a grow bag comes with a micron-rating. With a size ranging from as small as 0.2 microns to 5 microns, the probability of contamination reduces dramatically. If the mushroom grower takes adequate care during sterilization, mushroom grow bags can produce completely unadulterated colonies of mushrooms.

Securing the Growth Medium

The Monotub Tek is easier to manage than a mushroom grow bag. After the bag has been inoculated, the bag must be secured. The bag is either tightly wrapped with a twisted knot, with a zip tie, or with a steel wire. On the other hand, you just need to close and latch the lid of the tub in use in the case of Monotub Tek.

Method of Inoculation

In the Monotub Tek method, the inoculation is done by directly by mixing the mushroom substrate with the grain spawn. On the other hand, in the case of grow bags, the inoculation is usually done with a spore solution using a sterilized needle. If you are growing from spore syringe grow bags are much better, and if using pre-colonizegrain both are effective.

Ease of Harvest

When it comes to ease of harvest, both the methods have their pros and cons. In the Monotub Tek method, all the mushrooms grow inside the tub. To harvest, you need to open the lid. You can then use the tub for another harvest.

On the other hand, many mushrooms can directly be harvested from outside the bag without even opening it. However, some other varieties need more air, or grow as large clusters and for them, you may have to tear the bag open. So, it really depends on the type of mushroom as to how easy it can be to harvest it from the bag.

And the Winner Is…

Growing mushrooms using Monotub Tek and Mushroom Growing Bags are both popular techniques for cultivating mushrooms. Both require a certain level of care, focus, and learning to achieve high yields. Both methods are proven to grow good mushroom harvests even if you are a hobbyist or a small-time mushroom grower.

Depending on your scale of operation, availability of materials, available space, and type of mushroom, you can pick the technique that gives you better results.