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How to Grow Button Mushrooms: Grow Guide

Maybe you are an avid gardener or love to keep your home green with house plants. Or perhaps you love mushrooms and just want to grow some of your own. Whatever the reason, growing button mushrooms is a great entry point into the exciting and rewarding world of mushroom growing.

You may think that growing mushrooms is straightforward and easy. After all, they grow all over the place, right? Well, you would be right and wrong. Growing button mushrooms is rewarding and straightforward, given the know-how and the correct guidance. That is where we come in. Read on to discover the right way to grow and enjoy your very own mushroom harvest.

Why Button Mushrooms

Why button mushrooms? Besides their delicious flavor and the fact that they are suitable for numerous dishes, they are also one of the easier mushrooms to grow.

These factors make them a perfect starter mushroom for a beginner and an ideal addition to an ongoing mushroom garden. Furthermore, unlike many of the more exotic varieties of mushrooms, button mushroom spores are readily available from many suppliers.

Your Mushroom Garden: Materials

To start your mushroom garden, you will need to gather a few materials.

  • Growing Bed: this “bed” is the box in which your mushrooms will grow. We recommend using a container that is approximately 14 in (36 cm)  by 16 in (41 cm) and 6 in (15 cm ) deep. The box can be made of cardboard, wood, metal, or plastic, as preferred.
  • Plastic Sheeting: this sheeting lines the box to protect it from moisture.
  • Growing Medium: this is the substrate in which the mushrooms grow and feed. This medium is included in mushroom growing kits or made by DIY and adventurous types. The ideal medium is a mixture of manure, compost, gypsum, or vermiculite (more on this below).
  • Potting soil or Peat: you can buy this at any gardening supply shop.
  • Spores (or spawn): be sure to buy spores from a reputable seller to increase the likelihood that you will have a good harvest. The spores will come in an “inoculum,” or a medium with spores mixed in. This mixture is called spawn.
  • MIster: a mister is necessary for evenly moistening your mushroom bed as they grow.
  • Heating Pad: keeping the temperature of the growing medium stable is imperative for successful growth. A heating pad is a simple and effective way to achieve a stable temperature.
  • Cloth or Newspaper:  these items are necessary to ensure stable and continuous moisture in the growing medium. Be sure to have enough on hand to cover the medium in the growing-bed evenly.
  • Thermometer (optional): an easy way to make sure that your medium’s temperature is optimal. Not a necessary item, but valuable.

Your Mushroom Garden: Getting Started

There are two approaches to mushroom farming. You can start from scratch and make all of the necessary ingredients yourself, or you can buy a mushroom growing kit from a reputable vendor.

Here’s a video showing the opening and use of a mushroom growing kit, with more info below:

Mushroom Growing Kits

We recommend starting with a kit for first-time growers, as there is a bit of a learning curve. A kit will help you to learn the basics and get confidence. Not to mention the thrill when your first crop is harvested successfully.

Depending on the kit, the necessary growing medium and the spores will be provided. Some kits only provide the growing medium, so it is essential to check your kit before buying.

I recommend starting your search with this Button Mushroom Growing Kit from Amazon.

Growing Mushrooms From Scratch

For those with an experienced hand, a kit will still facilitate growing but making some of your ingredients will save money in the long run. For those who are up to the task, creating appropriate growing media is a viable option.

Making the Substrate

For those who want to make the substrate, it is essential to use suitable media and proportions. Mushrooms require a lot of nitrogen to grow. Furthermore, they cannot grow in a media that has already decomposed but is in a state of decomposition. 

The best substrate for button mushrooms is a combination of horse manure and partially decomposed straw. If you can not get your hands on partially decomposed straw (most of us probably), compost from your garden is a suitable replacement. Alternatively, mushrooms can also be grown in a pure manure medium if you want to keep things simple.

  • First, mix the compost (or straw) and manure in equal parts.
  • Next, add an equal half the amount of vermiculite or a portion of gypsum to your mixture. This addition will help aerate the mix as well as holding moisture and releasing it gradually.

Depending on how many trays you are planning to start with (one is a good start for newbies), be sure to make enough growing medium. If you make extra, be sure to cover it with a wet cloth or plastic to trap the moisture and keep it in a ventilated area as it has a distinct odor.

Here’s a video showing how to grow button mushrooms from a few mushrooms if you don’t want to start from scratch:

Fill the Growing Beds

Once you have your growing media, you are ready to start!

  1. Take your growing-bed and line it with plastic sheeting (a garbage bag works well for this).
    • The plastic sheeting prevents moisture from damaging your box (if you use metal, wood, or cardboard). It further helps maintain the growing medium’s moisture level.
    • As the mushrooms grow, the medium tends to shrink away from the sides of the box. Using plastic sheeting prevents mushrooms from growing in areas that are not suitable for harvesting.
  1. Fill the growing-bed with enough growing medium to fill the bed to about 4 in deep with a few inches to spare.
  2. Add water to the growing media. The ideal amount is enough to make it moist but not enough to saturate it.
    • Mushrooms need a damp environment to grow, but too much water can damage them.
  3. Take your “inoculum” or spawn (the mixture of mushroom spores and media they are mixed in) and spread it evenly over the top of the growing media.
    • Evenly spreading the spawn will help your mushrooms grow well and yield a maximum harvest.
  1. Using your mister, evenly mist the surface of the growing medium.
  2. Place a layer of damp newspaper on top of the growing media.
    • The newspaper will help trap moisture and evenly release it over time.
  3. Cover the growing bed with a plastic sheet (not touching the media) to create a high CO₂ environment and trap moisture.
    • A high CO₂ environment will encourage your mushrooms to “germinate” and start their first stage of growth.

Caring for Your Mushroom Garden

Now that you have “inoculated” your growing medium, you need to maintain an ideal growing environment for your mushrooms to grow. As mushrooms do not need light, you can place them in a suitably dark environment. Consider areas such as the attic, crawlspace, root cellar, garage, or closet (you get the idea).

  1. Place the growing-bed on the heating pad and set for 70℉ (21℃). Place the thermometer into the growing media to easily monitor the temperature.
    • The ideal range for growing button mushrooms is between 65-75℉ (18-24℃). Too hot, and you risk killing the spores and limiting your harvest.
  2. Mist the growing media with water twice a day. (source)
    • Be sure to check the moisture level carefully. If the medium is wet enough, do not add more water.

Under ideal growing conditions, you should start to see a web of white roots growing over the growing medium’s surface after 2-3 weeks. These are the mushroom “roots” or mycelium. If you do not see growth, be patient and wait. Growth may occur after a month or more.

Caring for Your Mycelium

As your mycelium grows, keep misting, ensuring a moist environment. After the mycelium has covered the growing medium’s entire surface, lower the heating pad to 50℉ (10℃) to encourage the mushrooms to “fruit” or grow.

  1. When full coverage has been achieved, add a layer of potting soil, peat, or compost (about 1 in, 2.5 cm).
    • This layer is called the “casing” and protects the delicate mycelium and provides additional nutrients for the growing mushrooms.
  2. Continue to cover the bed with wet newspaper and mist the medium to keep it moist. (source)

At this point, remove the plastic sheeting used to encourage mycelium growth. Mushroom fruiting is motivated by lower CO₂ levels and increased airflow. This will increase evaporation, so be sure to be vigilant.

Harvesting Your Button Mushrooms

After about a month, you will start to see mushrooms poking from the bed.

  1. When the mushrooms start to sprout, remove the newspaper to give them room to grow.
    • Continue to mist the growth medium as the mushrooms grow. Try to avoid soaking the tiny mushrooms, or they may abort their growth.
  2. Wait to harvest until you have mature mushrooms.
    • Mushrooms are ready to be harvested when the cap pops open.
    • Harvest the mushrooms by twisting the caps or cutting the stem with a sharp knife.
    • Fill any holes left by the harvested mushrooms with casing to allow for additional growth.
  1. As your mushrooms grow, keep an eye out for any that are off-color or withered. Remove and discard these and fill the space with casing.
  2. Continue to mist the soil as your mushrooms grow.

With proper care and attention, your mushroom harvest should last between 3-6 months.

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