Hardwood Oak Pellets for mushroom substrate

by | Dec 19, 2021

What is a Mushroom Substrate?

A substrate is a bulk material used by the mushroom to grow and produce fruiting bodies. It is the growth medium for the mushrooms themselves. Straw, wood chips, hay, and even cardboard make great substrates. There are many types of substrates available, but the most common ones include straw, sawdust, and wood chips.

The mushroom substrate needs proper preparation before being inoculated. Broken pieces of mycelium covered grains need to be added to the substrate. Mycelium will then quickly grow and consume the substrate. Once the substrate is fully colonized, the mushrooms are ready to fruit.

If you use a more modern and sterilized approach to inoculation, you are in your lab and using an air flow system to minimize contamination while transferring your grain spawn into your grow bags.

Common Mushroom Substrates

Oyster mushrooms are very popular because they’re easy to cultivate, and they taste delicious. Their flavor is somewhat similar to chicken or beef, but they also have a subtle mushroom flavor. You can use them in soups, salads, casseroles, stir fries, etc.

Oysters love what is called the Masters Mix. This simple to – use mushroom substrate grows very healthy, great looking, and tasting oyster mushrooms. The Masers Mix is a combination of 2 ingredients and water. Oak hardwood pellets, and Soy Hulls.

Other varieties or species of mushrooms prefer different forms of substrate. You should do your homework and choose both the substrate and the variety of mushroom you want to grow and pair them together.

What Makes a Good Mushroom Substrate?

A good substrate is made up mostly of carbon, oxygen, hydrogen, and nitrogen. These elements make up about 98% of the mass of the material. Nitrogen makes up most of the remaining 2%, but some other elements must be present to meet the 1 to 2 percent requirement. Sawdust, straw, and similar natural products do not have enough nitrogen to support healthy growth. You’ll need to add something else to get there.

Mushrooms require a pH of around 4.0 – 7.0. The optimal pH range for growing mushrooms is 5.0 – 6.0.

In order to grow mushrooms successfully, you need a healthy substrate. You need to add enough nutrients to feed the mushroom mycelia. Moisture levels should be kept around 70%. Competing organisms must be eliminated or controlled.

This is one of the reasons that Mushroom Media Online carries the Fast Fruiting Mix, which is their own pre-measured Masters Mix pellets. The fast fruiting mix is commonly referred to as the ideal substrate by mushroom farmers. With this product, you only have to weigh the pellets and the water. Then add those to your grow bag mixed.

Mushroom Media Online also carries many brans like oat bran that are used both for supplementation with oak pellets, and straw.

Using the Fast Fruiting or Masters Mix

Use 5 cups (2lbs) of the fast fruiting pellets then add 1.4 liters of water (3lbs).

Mix well and then add to your grow bag to sterilize.

Preparing Substrate

In order for mushrooms to grow, they must be placed into a suitable environment. First, water needs to be added to the medium. Then, you may also need to add a supplement to your substrate. Just as in the Masters Mix or Fast Fruiting Mix described above, where the soy hulls are the method of nutrient supplementation.

With other substrates that are prepared for optimal growth of another variety of mushroom, the supplementation used will vary. When using straw pellets, often growers supplement them with a grain for nutrition. Just remember you are going for the ultimate substrate for nutrition and the proper environment for the mushroom you want to grow. So, do your research.

All too often we see growers asking questions online about growing mushrooms in various waste and surplus materials. Remember, if you are growing mushrooms for sale at the gourmet market, you want your mushrooms to look, taste, and be their best.

As a business owner, I completely understand the desire to save money and increase profits. In the mushroom business, going as cheap as you can on the substrate is not the place to save money.

Think of it just as if you were growing another cash crop. There is a reason Dole grows pineapples on the Hawaiian volcanic soil. It helps grow the very best pineapples in the world. Your gourmet mushrooms will look, taste, and sell better when you use the very best substrate.


Different Substrates for Different Mushrooms

Different species of mushrooms prefer different kinds of substrates. Straw gives you a high yield, but your mushrooms look less attractive than if you grow them with sawdust (for certain varieties). You may want to experiment with different types of substrate before deciding how much money you’re willing to spend on growing mushrooms.

It all comes down to what your mushroom mycelium prefer as their ideal medium for mushrooms. So, doing your research is great, but testing is king. With all the varieties of mushrooms, it matters less what the mushroom culture at large says and more, what your testing results say.

Reishi, Lions Mane, and Oyster mushrooms, grow very well on straw. Standardized recipes work well for all the mushroom species listed here, but there are some slight differences in how each species grows on different types of materials. When in doubt, try the masters mix or fast fruiting mix. It is the most universally used substrate for gourmet mushrooms.

Now, if you are growing the common button mushroom, you will want to use a different substrate. They love soil with vermiculite, and manure. In my mind, that is a different form of mushroom growing all together. Growing common mushroom strains over gourmet mushroom varieties often means a large scale operation and more competition in most markets.

The Masters Mix

Oyster growers often use a mixture of wood chips or sawdust and rice hulls called “Master’s Mix” because it produces more than twice the amount of growth per square foot compared to other mixes.

Soy hulls are a great supplement for composting because they contain nitrogen and phosphorus. However, you should use them during the fall or winter months if you want to maximize nutrient availability.

Using Straw as a Substrate

Straw is a cheap material that works well for many kinds of mushrooms. Straw is the stem part of cereal crops, such as wheat, barley and oats. It’s essentially what remains after you remove the grain. In some cases, it’s considered an agricultural waste product.

Straw pellets are often used because of the tremendous savings on labor costs, increase in efficiency, and the benefits of a finer substrate.

Imagine no more chopping, and cutting straw. Just measure your pellets by weight, and your other ingredients and water, mix, and you are done.


Mushrooms can be grown on any substrate, but some are better than others. Brans, such as oat bran, are often added to help speed up growth. Too much supplementation can lead to contamination, however. So make sure your substrate is clean before you add supplements.

Growing Mushrooms on Coco-Coir

Cococonut fiber is another name for coconut coir. Coconut coir is a natural material that is often used as a substrate for mushroom cultivation. Although it is not very nutrient rich, it provides adequate amounts of nitrogen and phosphorus for healthy growth. However, because it does not contain any potassium or calcium, it should be supplemented with kelp meal or rock dust.

Coco coir is a natural material that supports mushrooms well. It also helps retain moisture, making it ideal as a growing medium. Cocoa shell is a waste product from cocoa beans, and it contains some nutrients. Pasteurization is required to kill off harmful bacteria.

Uses for Spent Mushroom Substrate

There are lots of ways to use your mushroom compost! You could make mushroom tea or mushroom wine, you could turn it into rich soil for new plants, you could use it as mulch around perennials, shrubs, and fruit trees, or you could even use it as fertilizer for lawns, gardens, and houseplants.

With a small amount of spent mushroom substrate, you should consider adding it directly to your soil as a fertilizer. You’ll likely see some benefits within a few weeks, but it could take several months before you notice any major changes in your plants.

It is also possible to recycle substrate as a source of nutrients for growing other types of fungi. However, there may be diminishing returns. You’ll likely need to supplement your substrate with something else to get the full effect.

Composting is a great way to recycle organic matter into soil nutrients. You can make money by selling your compost to farmers.

Some growers are now saving and bagging their spent substrate for sale to local flower growers, and garden enthusiasts. It helps the gardeners and turns a waste product into another income stream for their business.

Mushroom Media Online Logo
Mushroom Media Online Pallet

What Is Masters’ Mix?

Masters’ mix is a substrate blend pioneered be TR Davis of Earth Angel mushrooms. It’s blend of HWFP and soy hulls. Colonies grow fast and yield well. It encourages a large first flush, allowing for a quick turn around. It’s heavily supplemented and requires sterilization.

In order to grow mushrooms you need three things – air, water, and substrate.

Does Masters Mix Need Sterilizing?

Masters’ Mix is designed to be used as a sterile medium for growing microorganisms. However, it is also very prone to contamination because it is nutrient rich and contains no living microbes. To prevent contamination, you must use aseptic techniques during transfer. You may want to try growing your bacteria in another container first before transferring them into Master’s Mix.

Most growers use grain spawn bags to grow their mycelium through the spawning stage. Then they transfer this to their prepared substrate that has been sterilized and prepped. This provides the best change for a strong fruiting stage that may contain 3 or more flushes of healthy mushrooms.


The Advantages of Wood Pellets for Growing Mushrooms

Wood pellets, like hardwood oak pellets, are ideal for growing mushrooms when they are properly supplemented. Pellets are easier to measure, and work with than sawdust, and much cleaner as well.

Wood pellets are less likely to become contaminated. Due to the high temperature produced by the process of making the pellets, wood pellets are a non-toxic, sterile medium for growing mushroom. Since you are adding supplements to the substrate made with wood pellets along with water, you should still sterilize your substrate mixture for safe production before use.

Softwood or Hardwood Pellets?

Softwood pellets contain lignin, a chemical compound that makes them unsuitable for mushroom cultivation because it inhibits mycelium growth. Hardwood pellets do not contain any lignin, making them ideal for mushroom cultivation.

Pine is often used as a mushroom substrate because it contains antifungals. However, some sources state that it may actually inhibit growth. In any case, there are better choices available. Oak wood pellets are the most common used in gourmet mushroom production.

Is it OK to use heating pellets?

Again, mushrooms will grow on almost anything. The question should be, are heating pellets the best choice for my mushroom farm?

While heating pellets do come in a pellet form, they are not the same as pellets made specifically for use in mushroom farming. It is true that on the larger market, these pellets may be similar to BBQ pellets. But the best pellets are custom-made for mushroom substrate for safety.

You see heating pellets are often made from waste materials like used pallets. Those pallets can have any number of chemicals on them, or in the wood itself. No one knows how many of the contaminants may make it through the pellet making process. So the chances of contamination may be higher from these heating pellets.

When it comes to your substrate materials, just do not chance anything. You do not want any chance of contamination making it into your block of substrate. Ultimately, your mushrooms will be sold to the public in grocery stores, direct from your farm, or even via restaurants. So, be careful to use only the very best.

Use the best sterilization process possible

The best sterilization process known is to take your sawdust fruiting block, into the mushroom grow bags, and place it in a pressure canner, or sterilizer. By putting the substrate under pressure and using heat, you sterilize faster and better.

No matter the substrate mix, most common species of mushrooms will respond best to the sterile environment this creates in your substrate. Some mushroom farmers use the most complicated mushroom sterilization methods imaginable. Do yourself and your farm a favor and keep it simple and dependable. When you can afford the upgrade, choose a high quality All American pressure canner, or sterilizer for your sterilization efforts. These are what the old guys would refer to as the Cadillac of sterilizers. The gold standard if you will.