How to choose mushroom grow bags?

4 min readMar 7, 2021

When you think about mushrooms you tend to think about them growing in forests or fields. Well, that’s mostly true as mushrooms thrive in these environments but what about indoors mushroom growing? You can grow certain mushroom species in your own home! You may start thinking about how to perform this task and what sort of equipment you may need and here comes the big surprise… You can grow mushrooms by using specialized bags known as a mushroom grow bags, also known as spawn bags! You can use these specialized bags and grow some of your favorite mushrooms thanks to them. Let’s find out how you can achieve this.

What is a mushroom grow bag?

Ok, let’s first make things clear, you do not have to be a professional grower to manage to culture mushrooms as even enthusiastic hobbyists can make it. Meavien will guide you on how to choose spawn bags. When we are talking about a mushroom grow bag we are talking about a gusseted autoclavable polypropylene filter patch bag. Many unknown terms here but we can explain their meaning. So gusseted refers to the way the bag is folded so that it can facilitate the growing of mushrooms and at the same time it can prevent contamination from the air that can enter the bag after the sterilization.

Polypropylene is a thermoplastic that can sustain very high temperatures and won’t melt unless temperatures are sustained between 260 to 350 °F. This plastic is ideal for autoclave use as it is resistant to high pressures operating at 15 PSI and 250 °F temperatures. Finally, the filter patch as the name implies is the filter on the front of the bag. It allows the circulation of fresh air by blocking air contaminants such as mold, bacteria, and spores. Fresh air is vital for mushroom growing as, without it, mushrooms cannot grow.

How to use spawn bags?

Now that we examined what a mushroom grow bag is, let’s stress our focus on how to use it. In general, the most common uses of mushroom grow bags include sawdust fruiting blocks and spawn bags. Filter patch grow bags are an indispensable tool for making sawdust fruiting blocks. A large bag will typically make a 5 lbs fruiting block, including the weight of your spawn. A big-sized bag like this allows you to easily mix the spawn after inoculation, and the filter patch allows your mushroom culture to breathe while it grows throughout the sawdust. Once the mushrooms have fully colonized the bag you can either cut the top of the bag or cut the side of the bag so the mushrooms can fully grow.

In terms of the spawn, if you have it in a grow bag, it is easier to break up the spawn, mix it, and speed up the colonization. You can add up to 5 lbs of spawn in a large spawn bag and you can even use it to inoculate ten more spawn bags. The big advantage with mushroom grow bags is that you can reuse them as long as you haven’t cut the bag before when fruiting. However, you should keep in mind that the filter patch and the bag integrity decreases after many sterilization cycles, so be sensible when it comes to bag reusing and reuse for 2–3 times only the same bag and only if it is in good condition.

Three important things to consider:

As soon as you are ready to purchase the equipment you should keep in mind 3 main things:

The bag size.

As there are several different bag sizes available, you will need to consider what size you will choose. This will depend on the size of your sterilizer and on the quantity of the substrate you want to put in the bag. In general, the bigger the size of the bag the better the results are.

The bag thickness.

Bag thickness can range between 2.2 mil to 4.0 mil. Thicker bags are stronger and less likely to tear but they are expensive. It is recommended to pick the 2.2 mil bags but use them carefully as they are more likely to tear than thicker bags.

The filter size.

Filters have sizes and this depends on the pore size of the filter. Typically, filters can range between 0.2 to 5 microns. It is advised not to use a filter higher than 0.5 microns as higher than that can lead to a higher contamination rate. The one Meavien uses for its mushroom grow kits has 0.2 microns.

Final tips a successful culture

Finally, let’s see the last details for successful mushroom culture. It is recommended to use a filter sleeve to prevent post-sterilization contamination. You can use a Tyvek sleeve as a filter and place it between gussets and above the substrate. In that way, any air drawn into the bag during cooling off will be passed first through the Tyvek sleeve.

Furthermore, if you are planning to set up large-scale grows you can purchase 100+ mushroom grow bags already filled with substrate and sterilized directly from Meavien. You will skip using an impulse sealer and autoclave in this case, so it will save you a lot of time and money.

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By Paul S.

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