Inoculating Rice Bags with magic mushroom spawn

Growing magic mushrooms can be a rewarding endeavor for both beginners and experienced cultivators. One of the most accessible and efficient methods for home cultivation is using rice bags as a substrate for mushroom spawn. This technique leverages the simplicity and nutrient-rich properties of rice, making it an ideal medium for mushroom mycelium to colonize and eventually fruit.

Inoculating rice bags with magic mushroom spawn involves several key steps, from selecting and preparing the rice substrate to sterilizing the bags, introducing the mushroom spawn, and maintaining the optimal conditions for growth. Whether you are interested in this process for personal use, research, or expanding your cultivation skills, understanding the fundamentals of rice bag inoculation will set you on the path to a successful harvest.

In this guide, we will walk you through each step of the inoculation process, providing detailed instructions and tips to ensure a smooth and productive cultivation experience. From the initial preparation to the final stages of mushroom fruiting, you’ll gain the knowledge needed to produce healthy and potent magic mushrooms using rice bags.

Supplies:

• 6 bags of Uncle Ben’s 90-second Brown rice. Off-brand bags of brown rice can be used. DO NOT USE bags with herbs or seasonings. If using the substrate recipe below, you will want to inoculate all 6 bags of rice to have a 1:2 ratio with the substrate recipe. 
• One (1) Mycelium spawn syringe. Grain-to-grain or agar transfer is possible. I have found one (1) 10cc syringe or one (1) agar dish will inoculate 6-7 bags.
• First Aid Tape, also known as paper tape. Nexcare is the brand name but off-brand works. This prevents contamination while allowing FAE.
• Scissors.
• Lighter or torch.
• Gloves.
• Marker to write.
• 70% rubbing alcohol in a spray bottle.
• Recommended: SAB (Still Air Box), and bright light to view bags.

Prep:

Once you have your supplies gathered, wipe everything down with 70% rubbing alcohol. If possible, perform this in a SAB (Still Air Box), but if not, take steps to limit airflow and contamination by wearing masks, turning off fans/furnaces one-hour before starting, and sterilizing everything. Perform the below steps for each bag of rice.

1. Write the date and strain on the left-hand side of the rice bag.
2. Prepare 3 pieces, 2″ long, of first aid tape to cover holes.
3. Break the rice up and squish all rice grains to the bottom of the bag, then twist the top of the rice bag to compact the grains on the bottom.
4. Please ensure all rice grains have been pushed to the bottom using a bright light behind the bag, as stray grains can cause contamination. In this image, you can see grains stuck around the “AD” in “Ready” on the left bag, while the right bag has had the stray grains pushed down.
5. Open the spawn syringe, sterilize the needle with a butane torch or lighter, and wait just a minute to allow the tip to cool.
6. Insert the needle into the bag at a downward angle below the word “GRAIN” on the front of the bag.
7. Inject a small amount (1-2cc) and immediately cover the puncture hole with first aid tape. Tip: If the needle is clogged with a grain of rice and the plunger is not depressing, partially withdraw the needle without removing it from the bag and try depressing the plunger again.
8. Using your fingers as a clip to ensure no air and contamination get into the bag, diagonally cut the corner of the top of the bag off. Then immediately cover the hole using two pieces of first aid tape without removing your fingers.
9. Leave the bags of rice upright at room temperature (73-78 is ideal but not required). Colder temperatures can cause slow growth which can lead to loss due to wet rot and mold.
10. Over the next two weeks, you should periodically check the clear bottom window of the rice bag to see the growth. You should also see the bag expanding with gas that will be expelled through the first aid tape on the top corner.
11. Between days 7 and 14 after inoculating, you should do a break and shake on the bags to help distribute the mycelium throughout the rice. Where the mycelium has grown, the rice will be firm. Once all of the rice is firm and the clear view window on the bottom is completely white and fluffy, it is time for substrate.

If at any time you see green, the bag is moldy and needs to be tossed. Do not open the bag unless you are in a well-ventilated area and are wearing the proper facemask.