How To Open
A Grow Bag

Learn How To Open A Mushroom Grow Bag

What Is A Mushroom Grow Bag?

Mushroom grow bags are strong, heat resistant bags which are used to sterilise supplemented substrates for mushroom growing and spawn production.

Mushroom grow bags feature a filter patch to allow for fresh air exchange which is essential for the healthy growth of mycelium while ensuring that the substrate remains free from contamination.

Lion's Mane Mushroom Pakora Vegan Recipe
open a mushroom growing kit

How To Open A Mushroom Grow Bag

There is no singular correct answer. Most mushroom hobbyists prefer to leave the bag in place while making a small incision through the plastic to expose a layer of substrate that has been well colonised by a thick layer of mycelium. This method ensures that the block is protected and maintains high levels of humidity. 

Mushrooms will grow in search of fresh air. Mushrooms will typically form where fresh air and high humidity converge on the surface of the substrate.

A few exceptions are species such as king oyster and lion’s mane which will often try to form fruits beneath the plastic where humidity is highest. This is due to these species having a lesser need for fresh air exchange. In this case the bag may need to be adjusted to allow for the fruiting bodies or mushrooms to develop.

Removing The Bag Completely

This yellow oyster grow kit (pictured) has had the bag completely removed to allow for the growth of numerous sets of pins or primordia. Some growers may decide to allow for some sets of pins to remain trapped and abort.

By removing the bag completely, the risk of the grow kit developing contamination or dehydrating has increased.

This grow kit is being stored in a greenhouse with humidifier to ensure that it remains healthy.

How To Grow Mushrooms

Making A Single Cut

Making a single cut is one of my preferred methods for fruiting side-fruiting oyster mushroom varieties like the pink, blue, white, brown and phoenix oyster.

These species of oyster mushroom will begin to form primordia within days of being exposed to both fresh air and humidity along the newly exposed cut in the bag. Apply tape to each side of the cut to keep the bag tight which will reduce the number of stray pins forming beneath the edges.

The taped edges also helps retain more moisture allowing the grow kit to produce larger yields for longer.

Making A V or X-Shape

This method is similar to making a single cut, however a V or X-shape cut is made to expose a well colonised area of substrate.

These formations can result in impressive looking flushes, especially with the V-shape turning into some large heart-shaped flushes for Valentines day.

King Oyster Grow Kit

Opening King Oyster & Enoki Grow Kits

Some species like king oyster and enoki mushroom don’t require much fresh air exchange. For these species it is often recommended to allow them to begin form primordia within the bag before opening due to their high humidity requirements.

If fruiting is delayed a cut can be made in the top of the bag before resealing which will allow for increased fresh air exchange to stimulate growth.

Once primordia has formed the top of the bag can be removed leaving a 10 – 15cm tall edge to create a reservoir which will allow carbon dioxide to accumulate. This will encourage king oysters to develop their classic, thick meaty stems and for enoki mushrooms to grow long and slender.

4 Ways To Open A Mushroom Grow Kit

In this video tutorial we demonstrate how we open our mushroom grow kits using 4 different methods, removing the top, the v, the x, and the single slice. Follow the growth of these kits and their yields.

View Our Range Of Grow Kits

Who We Are

We’re a small scale producer of gourmet mushroom grain spawn and ready to grow kits located in South East Queensland. We’re passionate about fungi and we love sharing our obsession with the world.

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