Sterile Substrates - Frequently Asked Questions | North Spore (2024)

FAQs

Sterile Substrates - Frequently Asked Questions | North Spore? ›

Are sterile substrates guaranteed? Yes! North Spore stands behind its products 100%. Our mission is to help you successfully grow mushrooms, and we are here to help guide you on your mushroom cultivation journey.

To give the mushrooms you're growing a head start, sterilise high-nutrient substrates. Pasteurisation can be used instead of sterilisation for less nutritious substrates. Straw is a wonderful example of this. After all of the grain has been harvested, straw is the dried stalks of various grain plants.

Hardwood sawdust contains a rich blend of nutrients that provide essential support for the development of healthy mycelium, crucial for successful mushroom growth. The porous nature of sawdust creates an ideal structure for mycelium colonization, allowing for efficient nutrient absorption and moisture retention.

When sterilizing your substrate, longer and hotter is NOT better! A temperature of 121°C or 250°F will do the job. Just be sure the complete mass of substrate reaches that temperature for 30 minutes.

... Fresh mushroom substrate had an average pH of 7.56 (Table 1). Kumbhar (2012) reported an average pH of 7.3 for fresh mushroom substrate.

Mushroom substrates are the perfect breeding ground for unwanted microbes. If not properly treated through pasteurization or sterilization, contamination will lead to wasted crops.

Sterile substrates do not require refrigeration, we recommend storing at room temperature. If kept at room temperature and out of direct sunlight, all sterile substrates can be stored for several months before use.

Temperature Fluctuations:

Each mushroom strain has an ideal temperature range for growth. If the ambient temperature veers too far from this sweet spot, colonization can slow down or even halt.

The higher the inoculation rate or amount of spawn added to the substrate, the faster the mycelium will grow through the substrate. The substrate likely will not produce a larger amount of mushrooms, so a high inoculation rate means more money spent on spawn per pound of mushrooms.

Straw is a cheap and extremely effective substrate that works well for many types of mushroom species. Straw is the stem portion of grains such as wheat, barley or oats – it's basically what is left over after the grain itself has been removed. In many ways, straw is an agricultural waste product.

How do you sterile a mushroom substrate? ›

High-temperature steam must be constantly produced at around 121° C (250° F) or 0.5 bar at average cycle times of 6–8 hours to effectively sanitise the mushroom substrate and to ensure complete biological inactivation.

Put the pot on the stove and bring the water to a boil. Gently submerge the bag or container with the substrate into the boiling water. Maintain the water at a simmer, not a rolling boil, to keep it at around 160° F (71° C). Pasteurize the substrate for at least 1 hour.

Substrate may also be treated to reduce potential fungal or bacterial contaminants. Two common methods of substrate treatment include: Cold water with hydrated lime: Mix 6 grams of hydrated lime for every 1 gallon of water. You may need to add more or less depending on the pH of your water.

It just makes sense to grow mushrooms in coffee grounds. You make wonderful nutritious oyster mushrooms out of a bountiful waste resource that is still rich with nutrients. You can return the now composted grounds to enrich your soil at the end of the growth cycle to complete its life cycle too.

A) lots of water dripping shows that the substrate is too wet. b) a few drops released with some pressure show that the substrate is well watered. If it is too dry then with no drops will be released with pressure.

Therefore, sterilizing these substrates becomes essential as it eradicates all living and dormant organisms and fungal spores, providing the best possible start for mushroom mycelium. However, low-nutrient substrates like straw, sugarcane bagasse, coco coir, hardwood sawdust, and cardboard only require pasteurization.

If you have some mushroom growing experience and are ready to try growing medical mushrooms or fussy gourmet species, you'll need to sterilize your substrate. For small home growers, the easiest way to do this is with a pressure cooker that can maintain a pressure of 15 PSI.

For the oven method just preheat it to 170 degrees and cook the bulk substrate on baking pans with a tinfoil cover for at least 2.5 hours. To use the steam method, bag the substrate in filter patch bags and cook it in a pressure cooker or steam it until it reaches around 160-180 degrees F.