How To Grow Portobello Mushrooms [All You Need To Know]

Who doesn’t love a good mushroom? Real mushroom lovers often crave to grow their own, and today, we will tell you how to do that!

Portobello mushrooms are beautiful, large mushrooms that taste heavenly when grilled. These popular mushrooms are often used as a vegan alternative to beef burgers, owing to their chewy texture. Moreover, they are relatively easy to grow at home and don’t require too much attention or maintenance. 

In today’s guide, we will tell you everything you need to know about growing Portobello mushrooms. Depending on whether you want to grow them outdoors in the garden or indoors at home, there are a few aspects you need to remember. 

So without further delay, let’s begin the guide. 

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How To Grow Portobello Mushrooms

Fried champignon mushrooms in a cast-iron old pan on an old dark wooden rustic background for frying. Top view.

About Portobello Mushrooms 

The internet can be a fascinating but also a confusing place. If you Google Portobello Mushrooms, you will come across several other terms like “Portobella Mushrooms,” “Cremini Mushrooms,” and “Crimini Mushrooms.” So, what is the difference?

Let us address the first conflicting issue – Portobello vs. Portobella Mushrooms. There is absolutely no difference between them. The difference in spelling or pronunciation lies in who you are asking. Technically, both of them are correct.

Now, what are Cremini or Crimini mushrooms? Cremini mushrooms are the smaller (or younger) version of Portobello mushrooms. The former is around 3 to 7 days younger and slightly smaller than the latter. 

Again, the difference between Cremini and Crimini simply lies in their spelling and how individuals prefer its pronunciation. 

MarDona 2oz Dried Portobella Mushrooms
  • Dried Portobella Mushrooms
  • In re-Seal Pouches

Growing Portobello Mushrooms

The simplest way to grow these beautiful mushrooms is to purchase a growing kit. Remember to mist it regularly and allow the mushrooms to breathe, and that’s about it. Growing Portobello Mushrooms this way is straightforward and convenient, not to mention a lot of fun. 

The real challenge begins when you decide to make a DIY growing kit. To do this correctly, you need to purchase the mushroom spores from a reputed store and choose the right kind of soil for them to thrive.

Let us begin by discussing how to grow Portobello Mushrooms outdoors.

Growing Portobello Mushrooms Outdoors

Growing Portobello Mushrooms outdoors can be fun but requires a little preparation. For starters, ensure that the temperature outside is suitable for these mushrooms to grow and thrive. As such, the temperature outside must not rise above 21°C (70°F). It should also not fall below 10°C (50°F). 

Next, you need to prepare a raised bed to plant the mushroom spores. Begin by building a bed that’s at least 4 feet long and wide and is 8 inches deep. 

You also need to procure well-seasoned compost (preferably manure-based) and fill the bed to at least 5 inches high. Take a few pieces of medium-sized cardboard and cover the raised bed with it. Also, cover the top of the bed with a black plastic sheet. 

This process is essential for sterilizing the bed. It engages the process of solar radiation, which automatically destroys germs, foreign bodies, and prepares the plant bed for growing mushrooms. Ensure that you keep it covered for at least two weeks, enabling the process to complete successfully. 

Planting The Portobello Mushroom Spores

After two weeks:

    1. Remove the cover carefully to expose the sterilized plant bed.
    2. Take the mushroom spores and sprinkle about an inch of them over the soil.
    3. Mix the soil lightly (be gentle and avoid unsettling it).
    4. Allow it to sit for a couple of weeks undisturbed. 

In just a few weeks, you may notice something called the “mycelium” across the surface. This is a white web-like film that indicates that the spores are beginning to grow.

The next step is to apply a thin layer (1-inch) of moist peat moss. Cover this layer with an old newspaper and mist it lightly with water at least twice a day (for ten days). Depending on personal requirements and how large you want the mushrooms to grow, harvest them once you feel they are ready. 

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Growing Portobello Mushrooms Indoors 

Growing Portobello mushrooms indoors is relatively easy as long as you take the right measures. It is essential to build a planting bed, which we will discuss in the following section. Depending on how many mushrooms you wish to grow, build an adequately spacious bed. 

  1. Building The Plant Bed

The process is similar to building a raised plant bed outdoors in the garden. Use a tray or build a planting bed from scratch using wood or cardboard, which is at least 8 inches deep and 6 inches long. However, the size may vary according to your needs. 

Purchase a bag of manure-based compost and fill the tray with it to about 6 inches deep. Do not fill the entire 8 inches, as the mushrooms require room to grow high. Moreover, this leaves adequate room for adding peat moss and additional soil at a later stage. 

  1. Sterilizing The Soil

As we discussed in the previous section, it is vital to sterilize the soil before planting mushroom spores. This is especially important if you plan on keeping the planting bed outdoors. 

Lay a single piece of cardboard over the soil (before adding the mushroom spores) and cover it with a black plastic sheet. Ensure that the soil is packed tightly inside before tying the top of the plastic sheet securely. Place the bed outdoors in the sun for two weeks, ensuring any harmful bacteria or contaminants are naturally killed in the process.

In case there is rainfall, don’t disturb the bed and let it remain outdoors. Rain is good for the soil and mushrooms, so you don’t need to worry.

If you don’t want to place the bed outdoors, keep it in a dark corner of your basement, shed, or any other darkened area. Ensure that the temperature of the area does not dip below 10°C (50°F) or rise above 21°C (70°F).

Consider monitoring the soil temperature with the help of a soil thermometer. This isn’t compulsory, but doing it will help you track the soil temperature accurately. 

  1. Adding The Mushroom Spores 

You can easily purchase Portobello mushroom spores from any local gardening shop or online store. Wear rubber gloves before starting the process. Then, add the mushroom spores into the soil and mix it lightly without disturbing the soil too much. Pat down the top layer gently once you are done. 

Add some peat moss over the soil before covering it with a layer of newspaper carefully. Add another light layer of peat moss over it. Mist the layer with water twice a day for ten days, ensuring that the mushrooms have a moist environment to thrive. 

After about two weeks, you may notice the tell-tale white webbed film, which tells you that the mushrooms are beginning to grow. Place the newspaper back and continue misting it daily. Once you are satisfied with the Portobello mushrooms’ size, harvest them and add them to your food!

A lot of agaricus bisporus mushrooms growing in a forest

Summing It Up

The process of growing Portobello mushrooms is relatively simple, and the results are stunning.

You may refrigerate the mushrooms after harvesting them or add them to your dishes. Of course, ensure that you clean them thoroughly before doing so to avoid contaminants and soil in your food.

It is best to wait until your Portobello mushrooms’ edges are flat and white instead of curled. This tells you that the mushrooms have reached full maturity.

Let us know how your mushrooms turned out. Until next time!

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