Get to know your Mushroom Substrates

mushroom substrates

All About Mushroom Substrates

One of the first things you do when creating your mushroom growing kit is to collect your equipment. Depending on your preferred mushroom choice you could need a variety of different items from bags and/or trays to inoculation guns and scalpels, but the one thing that every mushroom grower needs is a substrate to grow their mushroom in. Be it straw, manure, rye berries/rye grain, or millet and seed, a good, nutrient-rich substrate is vital to your mushroom growing success.

What is a substrate?

The substrate is the nutrient-dense medium that serves as the food and support for your growing mycelium and fruits.

Pretty simple right? Well, something to bear in mind as you get starting growing is that not all substrates are created equal. Researching your particular strain of mushroom before getting started and choosing the proper growing medium is one of the best things that you can do as a grower to ensure you produce a successful crop.

Types of Mushroom Substrates


Although it may be one of the messier of the substrate options, straw is an excellent choice for beginner growers as it is readily available, relatively cheap, and easy to use. The preferred choice of growers of oyster mushrooms, enokitake, and garden giants as well as many other species.

miniature bales of shredded wheat straw

Brown Rice Flour

Made from, you guessed it, brown rice, brown rice flour is a wonderful, readily available choice especially when combined with vermiculite. It is an excellent choice for growing a variety of gourmet mushrooms including oysters, shiitakes, and reshis.

brown rice flour


Made from a naturally occurring mineral called mica, vermiculite is an excellent additive to other substrates to help increase the nutrient density.

vermiculite for mushrooms


Manures are a nutrient-rich and excellent choice for a substrate. Cow manure or cow dung is generally sold moist, whereas horse manure is generally sold dehydrated which is nice because you are getting all the nutrition without paying for the water. This is a particularly nice attribute if you are planning to order online. Manure or dung is generally used in conjunction with something like straw, although if leeched of its ammonia, horse manure, in particular, can be used as a standalone to grow certain mushrooms like inky caps. White button mushrooms, portabellas, and creminis, however, prefer a mix, preferably compost or straw or both.

Rye Grain/Rye Berries

While a plethora of grains are available for growing mushrooms and mycelium including millet, wild bird seed, rye grass seed, and even popcorn, rye is hands down the most popular choice. Rye grain, or rye berries as they are known in the south, are nutrient-dense, ultra-absorbent, and mushrooms just love them. Rye grain can be used for most edible mushrooms either by itself or mixed with other substrates.

rye grain and rye berries

Ready to get started?

Once you have chosen your species of mushroom and done a bit of research you are probably ready to move on to trying your hand at growing. No matter what substrate you choose, remember to be sure you have all of your supplies at hand before you get started to ensure that you have a successful experience. Browse all substrates available for purchase.

Still need to purchase your supplies? Everything you need to get started can be found here in our shop. Still not sure what all you need? One of our knowledgeable staff are happy to help.