How to Grow Mushrooms at Home

Embark on an exciting journey into mushroom cultivation, where patience and nurturing lead to a bountiful harvest of delicious, homegrown fungi. Mycology, the study and production of mushrooms, is a vast field. The basics, though are easy to learn and all you need to be a successful grower at home.  

This comprehensive guide will walk you through the entire mushroom growing process, from start to finish, equipping you with the knowledge and confidence to navigate each stage successfully.

If you are looking for a related project to do with your kids or in a classroom, be sure to check out our Mushrooms are Decomposers activity. 

Understanding the Mushroom Life Cycle

It is great to have a basic understanding of the specialized vocabulary and life cycle of a mushroom before you get started. If this is your first experience growing and learning about mushrooms, don’t worry. We have included a basic review below.

To start understanding fungi, let’s begin with what they need to survive. Fungi need many of the same things that all other lifeforms on earth need to survive. They just get them in different ways. 

 The Basic Needs of Fungi

• Nutrients - from the substrate they digest, be it wood chips or coffee grounds.
• Water - from the moist substrate and the humidity in the environment
• Fresh Air - mushrooms breathe in oxygen and exhale carbon dioxide just like us
• Light - mushrooms do best with light that mimics the dappled sunlight they would get from living on the forest floor. Indirect sunlight, like a shady spot outside or inside on your counter. 
• A Temperate Environment - most fungi like to produce mushrooms between 55-70℉. A little higher or lower is okay for oyster mushrooms. 

The Life Cycle of Mushrooms

Mushrooms grow in four basic stages. This cycle has more complex substages, but you don’t need to be an expert to grow mushrooms at home. In fact, you will only really be working within the middle two stages for this project. 

1. Spore germination
2. Colonization
3. Fruiting
4. Sporulation

Before we move on to understanding how these stages affect the growing you will do, let’s review the basic terminology used in mycology.  

Here is a simplified explanation of fungi terms:

Mycelium - This is the largest part of the fungus that lives (mostly) underground. It resembles a large tangle of thin white threads, similar to plant roots.

Substrate - This is the food and home for the mycelium. Mushrooms that we eat typically grow on substrates like wood, straw, coffee grounds, or other agricultural leftovers like coconut husks, wheat bran, or cottonseed meal.

Substrate Block - This is a bag filled with mycelium and its food (substrate). When you open the bag, mushrooms start to grow.

Spore - This is how fungi reproduce. Spores are tiny and can join with another spore to create new hyphae.

Hyphae - These are long, thin threads that make up the underground mycelial network of a fungus. They help the fungus grow and get food from its surroundings by spreading out and branching. Think of them as the fungus's building blocks.

Sporulate - This is when a mushroom finishes growing and makes spores. Mushrooms should be picked before this happens or moved outside so the spores don’t spread indoors.

Fruiting Body - This is the part of the fungus we see and eat, commonly known as mushrooms.

Fruiting Chamber - This can be any place set up for mushrooms to grow. It maintains the proper humidity, temperature, and airflow for mushrooms. Fruiting chambers can be small tabletop kits like the one pictured below all the way up to massive climate-controlled warehouses. 

Inoculation - This is the process of adding mycelium to fresh food (substrate) so it can grow.

Spawn or Mushroom Spawn - Any pre-inoculated substrate that contains mushroom mycelium. It is often sold as plugs made from compressed sawdust or rice bran. 

Spawn Run - This is when mycelium spreads through its food (substrate).

Pins or Primordia - These are baby mushrooms just starting to grow.

Understanding the Stages of Mushroom Growth

When growing mushrooms on a small scale, you will start with either an inoculated substrate block or mushroom spawn. Mushroom spawn represents the completion of the first stage of the mushroom life cycle. The experts have already done the spore germination for you so you don’t need to worry about contamination with mold or any fungi other than the ones you are trying to grow. You come in at the second life cycle stage, colonization, which we will cover below.

A mushroom block has already gone through both the first and second stages of growth. It was inoculated with germinated spores and allowed to go through its colonization phase in a controlled environment. When you receive your block it is ready to fruit. Most fruiting blocks must be set up as soon as they arrive, although they can be stored in the fridge for up to a week if needed.

Preparing for Mushroom Growing

The first step in growing mushrooms is deciding what kind you want to grow. There are a few excellent choices to get you started. Some are more forgiving than others, so start where you feel comfortable.

Best Mushroom Varieties to Start Growing:

• Oyster mushrooms, the easiest to grow and most forgiving of all mushroom species. Oysters also come in fun colors, including blue, pink, and yellow.
• Lion’s Mane, this mushroom has a unique shape, is easy to grow, and is very versatile in cooking. 
• Pioppino Mushrooms or Black Poplar Mushrooms are relatively easy to grow and have a nice, almost crunchy texture. 
• Shitake mushrooms are great to grow from mushroom blocks but have a long incubation time and are more challenging to grow using spawn.  
• For more info on good mushrooms to start with check out this video Top 5 Gourmet Mushroom Varieties to Grow | GroCycle

Choosing the Right Mushroom Variety for Your Growing Conditions

Different mushrooms have different environmental requirements for ideal growth. Even different types within a variety can be better suited for your growing space. For example, some pioppino species like to grow in cold temperatures, like an unheated basement, while others would rather be in a warmer spot, like the top of your bedroom bookshelf.

When you order your mushroom fruiting blocks or spawn, check the growing requirements for the varieties you want to grow. You will have a lot of control if you are growing indoors, but outdoor grows less so. 

Essential Equipment and Supplies for Growing Mushrooms at Home

In many cases, supplies can be cobbled together from things you have already around the house. Or you can purchase a kit to use with your experiment. We like the Bootstrap Farmer Mushroom Grow Kit because it has both a humidity dome and a blackout dome for all the growing phases. You will need: 

• Mushroom spawn or mushroom substrate block
• Watertight growing trays 
• Humidity domes or another covering to maintain proper humidity
• Blackout domes or other lightproof cover 
• Spray bottle for misting to maintain humidity
• Optional: hydrogen peroxide or alcohol for sterilizing equipment
• Sterilized substrate for growing mycelium can be any of the following. (More on this process in the instructions below.)
• Coffee grounds
• Straw
• Cardboard
• Sawdust
• Wood chips
• Wheat bran
• Coco coir
• Wood pellets

Setting up a Suitable Growing Environment 

The two most essential factors in the environment you will want to set up are temperature and lighting. Mushrooms grow best in even low temperatures, 55℉-70℉. Some varieties will need to stay at the lower end of that range. 

You will need two distinct lighting conditions: darkness for the incubation period and low-dappled or indirect light for the fruiting phase. The darkness should be somewhere that you can ensure airflow. Remember that mushrooms need to breathe oxygen, and stagnant air can encourage unwanted mold growth. 

Humidity is also essential to proper fruiting, but it can be easily controlled by misting your grow once or twice daily. Since mushrooms like high humidity, it is unlikely that you will need a way to lessen the ambient humidity.  

Now that you are set up to start growing we will move on to the steps you need to take to grow great mushrooms. If you are starting with mushroom substrate blocks you can skip down to Step 3. If you are using spawn, read on. You can also come back and use your spent fruiting block as spawn later. 

Step 1: Inoculation

Inoculation is most often done with small amounts of already myceiliated material added to a large batch of sterilized substrate. It can also be done with a syringe of liquid-suspended spores when you get a little more advanced.

Pasteurize your chosen growing substrate from the list below. 

• Coffee grounds
• Straw
• Cardboard
• Sawdust
• Hardwood chips
• Wheat bran
• Coco coir
• Wood pellets 

To properly pasteurize the substrate and avoid contamination, you will need to maintain a temperature of at least 167℉ for two hours. The simplest way to do this for small quantities is on the stove in a large stock pot with a lid. You can also use a pressure cooker at a higher temperature for less time to speed up this step and achieve a sterile substrate. 

• Place about 25 cups worth of substrate in a large pot. This is enough for one to two 1020 trays like the ones included with the mushroom growing kit. 
• Fill with water to cover and bring to a boil.
• Cover and simmer on low temp for at least 2 hours. Add water if needed to keep covered.
• Drain excess moisture and cool. 
• The moisture level should be similar to a wrung-out sponge.
• Place in a clean container until ready for use. (Should be inoculated as soon as possible to avoid mold growth.)

Keep Your Growing Space Clean.

Sterile equipment is crucial to good mushroom growth. Spores from other fungi can be present in the air, on our clothes, and hands. Always wash your hands before working with mushrooms. Sterilize your equipment by washing it with hot, soapy water and finishing with a mist of hydrogen peroxide or alcohol.  

Once all of your equipment is clean and your substrate has cooled to below 70℉, you are ready to inoculate. When mixing your purchased spawn with the substrate, follow the ratio instructions that came with it. Too much spawn and there will not be enough food; too little spawn and the inoculation phase will take much longer and be susceptible to mold growth. 

Break up the spawn into the smallest pieces you can and mix it thoroughly with the substrate. After mixing place the blackout dome over the tray and leave the vents just barely open. If you will be placing the trays somewhere that contamination is possible you can cover the vent holes with a coffee filter. This allows air exchange but prevents unwanted spores from getting in. 

Step 2: Incubation and Colonization

Factors affecting incubation and colonization rate include temperature, humidity, and gas exchange. Humidity must remain high throughout the process. Because the dome will stay on and the substrate is already moist, you may not need to mist the inside of the dome until the fruiting phase. The temperature should stay as close to ideal as possible, and swings should be avoided. A small amount of gas exchange is vital since the mycelium needs oxygen to grow. Mushrooms also exhale CO2, so you need to provide a way for them to breathe. 

If the temperature or humidity factors are too low or too high, you will see slow colonization of the substrate and possibly mold growth. If there is no gas exchange, growth will slow. If there is too much airflow, the mushrooms may fruit before they fully colonize the substrate. 

How Long do Mushrooms Take to Grow?

Successful colonization takes about 2-4 weeks, depending on the variety you are growing. You will know that the incubation is working when the white threads of mycelium begin to spread through the substrate. After a few weeks, the mycelium will form a thick white mat over all of the substrate; this process is the colonization stage of the growth cycle. Once this process is complete, you can start the fruiting stage. 

Step 3: Initiating Fruiting

Triggering fruiting in most species of mushrooms requires increasing the humidity, light, and air exchange. For easy-to-grow mushrooms, this is enough to trigger the fruiting phase. 

• Remove the blackout dome and replace it with a clear humidity dome. 
• Mist the inside of the dome to increase humidity. Do not spray the mycelium directly.
• Open the vents completely. If there is low airflow in the room where you keep the fruiting mushrooms, prop the lid open slightly.
• Place the tray in an area with indirect sunlight or brighter artificial light. 

Maintain these conditions for the 1-2 weeks needed for your mushrooms to fruit. Mist the inside of the dome once or twice a day. You should start seeing pins form within a few days. If you do not see the signs of pinning by the end of week one, increase the airflow and humidity.

Step 4: Mushroom Development and Harvesting

Mushrooms will continue to develop during the first flush for a week or two. The pins will proliferate into full-sized mushrooms quickly. Check on them every day and keep misting for humidity levels.

Signs of Maturity for Harvesting Mushrooms

Each mushroom variety has its maturity signs. 

• Oyster mushrooms are ready for harvest once the outside edge is curled under and feels similar to the curve at the top of your ear. 
• Shiitakes are ready once the cap has fully separated from the stem.
• Most mushrooms that have a veil underneath should be harvested just before the veil separates from the stem. 
• Lion’s mane are ready when the spines are around a ¼ inch long.

Heat, humidity, and light all affect the speed of growth. 

Proper Mushroom Harvesting Techniques

Use a sharp knife to cut the mushroom even with the surface of the substrate. Harvest mushrooms as soon as they are ready for the longest shelf life. Use your bounty immediately or store in a paper bag in the fridge.

Step 5: Subsequent Flushes

With a little extra attention, you can often get a second and even third flush of mushrooms off of your substrate. Subsequent flushes will usually be a bit smaller and less plentiful, but they are worth aiming for. 

In most cases to trigger subsequent flushes within 1-2 weeks you will want to:

•  Mist the inside of your blackout dome again.  
• Close up air vents 
• Move the block into a darker, cooler spot
• Allow the block to rest until you see new pins forming
• Return to step 3 and follow the instructions again

If your mushroom substrate gets too dry you can soak it in water for 2-3 hours, drain it and then try to trigger a flush again. After 4-8 weeks the substrate will have been all used up and stop producing mushrooms. At that point, you can break it up and add it to your garden as mushroom compost. 

Once you have mastered these somewhat simple steps you can think about adding mushrooms to your plan on How to Make Money on Your Homestead. 

FAQs

How long does it typically take for mushrooms to grow from start to finish?

With purchased spawn mushrooms generally take 4-8 weeks to begin fruiting. This can vary widely with different varieties but those mentioned in this article should produce within that time frame. 

With mushroom blacks that arrive ready to fruit, you should see mushrooms forming in 1-2 weeks. 

What are the ideal temperature and humidity levels for mushroom cultivation?

It depends on the variety you are growing, but most culinary mushrooms grow well at temperatures around 65℉ and humidity levels between 80% and 90%.

Can I grow mushrooms indoors? What are the requirements?

Yes! You can definitely grow mushrooms indoors. You just need a little shelf space for a kit and a room with stable cool temperatures and indirect light. 

How do I know if my mushrooms are ready for harvesting?

Each mushroom variety has its maturity signs. In general you will want to harvest your mushrooms when they are a similar size and texture to what you have seen in pictures or what is recommended by the spawn provider you bought your block from. 

Can I reuse the growing medium for subsequent grows?

No, after the subsequent flushes are done, the substrate has been exhausted. The mycelium has digested all the fungi's food. At that point, it makes an excellent additive to garden soil or compost. 

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