How-to: The Beginner’s Guide to Preparing Mushroom Grain Spawn

Growing mushrooms at home is not only fascinating but surprisingly easy, even with everyday household items. This article delves into the world of preparing mushroom grain spawn, a crucial step in home cultivation. We’ll explore a variety of grains you can use, including whole oats, whole corn horse feed (Producers Pride is a commendable brand), wild birdseed, millet, rye, popcorn, wheat berries, brown rice, and different colors of milo. These grains are readily available at local feed stores, online retailers like Tractor Supply, or even your local supermarket.

Grain spawn acts as the ‘seed’ from which mushrooms grow. It involves sterilized grain that’s been inoculated with mushroom spores or mycelium. This process is the backbone of mushroom cultivation, providing a nutrient-rich environment for the fungi to thrive.

Different grains offer unique benefits. Some cultivators choose grains based on nutritional content, cost, or the specific preferences of their mushroom variety. While many grains require rinsing to remove dust and impurities, a mix of whole oats and whole corn horse feed can often be used without rinsing, saving water and time.

Begin by rinsing your chosen grain. This step is crucial for removing dust and impurities that might interfere with the cultivation process. However, it’s important to be mindful of water usage; avoid over-rinsing to conserve this vital resource. After rinsing, proceed to boil the grain. Most varieties require about 30 minutes of boiling, though smaller grains like milo need only about 15 minutes. If you’re using a mix of whole oats and whole corn horse feed, you’ll find they often require minimal rinsing, further conserving water.

Once boiled, strain the grains and let them dry. You can use multiple strainers, a window screen, a sweater dryer, or spread them on a cookie sheet. The grains should dry for about an hour, but you can use the toilet paper method to check if they’re ready. Press a piece of toilet paper against the grain; if it sticks or leaves a wet mark, the grain is too wet.

Pack the dried grains into 0.2 micron plastic mushroom spawn bags or modified canning jars, ensuring not to overfill them. Leave some space for air exchange

When using a pressure canner, raise the bags or jars off the bottom, using jar lids under the raiser to prevent direct heat contact.

Pressure cook the grains for 90 minutes at 15psi. Fill the canner with enough water – usually about 2500-3500 ml – so that the bags or jars are covered by at least an inch of water. Once it reaches 15psi, wait 5-8 minutes, then slowly walk back the heat until the rocker barely moves. This prevents bag melting and grain overcooking.

The easiest method is to prepare the grains and pressure cook in the evening, allowing the canner to cool overnight. Avoid opening the canner until it has fully cooled to prevent contamination.

Creating your grain spawn is a fulfilling part of mushroom cultivation. Experimenting with different grains and methods can enhance your experience. We encourage you to share your experiences and tips with the community!