How to Use Sterilized Grain Bags

How to Use Sterilized Grain Bags

IMPORTANT 1st step

Make certain to provide the cleanest environment possible! Sterilize entire area for minimum contamination. Use sterilized glove box when available.

After injecting with needle the black round injection site will self close.
The white square filter patch located at the top of the bag allows proper gas exchange.


To begin:
1. Wipe the syringe needle and the injection site with an alcohol swab
2. Pull the syringe needle cover away from the syringe- be cautious not to accidentally stab the bag (speaking from experience)
3. Sterilize the needle with flame until it is red hot and allow to cool for a few seconds.


Push the needle about 1/2 inch into the bag and inject spores. Pull the needle half way out and angle it in a different direction and inject another 1-2 cc’s of spores We recommend a total of 4-5 cc’s of spores per bag. Depending on how easily/ affordably you can access spores - the more you use, the faster it grows!

Stand your sterilized spawn bag upright and unroll the top if folded, pull sides apart, try not to touch filter while doing so.


Keep your spawn bags in a warm, dark spot (75-77 degrees optimally) and try to leave it alone!


Spawn bags colonize from the inside out so you will most likely won’t see any mycelium growth for 7-14 days. Spawn bags gen- erate their own internal heat while colonizing so the internal temperature of the bag is usually 3-4 degrees warmer.


Around day 10 - 14 you will see white mycelium slowly spreading- at this point I always check carefully for mold (black or off colored spots in bag) to make certain I did not accidentally contact mold during injection process.


Spawn bags will colonize fully on their own with- out doing anything except maintaining temps.

Patience is once again a virtue! 
Spores can germinate anywhere from 30 to 60 days, it is  helpful to let your bag fully colonize before moving to the next step. However 14 days into this process if your bag is primarily covered in white mycelium gently break up the mycelium up by kneading the bag with your fingers. Be careful not to squeeze to tight to pop the bag and avoid puncturing with fingernails! I love this process as I now my bag is moving in the right direction. 

After breaking your bag up, reform the grain so it all sits back on the bottom and doesn’t create air pockets. Put it back in incubation spot and let it do its magic! Once again try to leave it alone for two to three more weeks.  The bag is ready when you have a completely white solid block of mycelium. The more solid the mycelium the less likely it will allow mould in if it accidentally comes into contact. In fruiting chamber.

There is a large variation in colonization rates of grain bags. If you have used jars in the past, remember that grains grow at different rates. End results depend on how patient you are in allowing for full germination.


Leave a comment

Please note, comments must be approved before they are published