HomePlant Care and TipsPortobello Mushrooms Information and Nutrition Facts

Portobello Mushrooms Information and Nutrition Facts

Ever heard of Portobello Mushrooms? Are they edible? Let’s dive deep into all the details along with how to grow them!

Portobello Mushrooms 1

If you want a culinary and nutritional powerhouse, then don’t miss Portobello Mushrooms. Whether you’re grilling, stuffing, or sautéeing, this versatile fungi offers more than just a meaty texture; it’s a treasure trove of flavor and health benefits.

Click here to learn about the Common Missouri Mushrooms

Portobello Mushrooms Information


Portobello Mushrooms, also known as Agaricus bisporus, are essentially mature white button mushrooms. Originating in Europe, these mushrooms have now become a staple in various cuisines around the world.

The name “Portobello” is believed to have been popularized in the United States and is likely derived from the Italian spelling “Portobello,” which is a region in Italy.

The cultivation of Agaricus bisporus dates back to the 17th century in France. However, Portobello mushrooms gained significant popularity in the United States during the late 20th century, especially among vegetarians and health-conscious consumers.

Originally, these mushrooms were often discarded or overlooked due to their size and appearance, but they eventually found a place in gourmet cuisine.

Botanical Classification

  • Kingdom: Fungi
  • Class: Agaricomycetes
  • Order: Agaricales
  • Family: Agaricaceae
  • Genus: Agaricus
  • Species: A. bisporus

Read How to Grow Magic Mushrooms here

Culinary Uses

Portobello Mushrooms are celebrated for their meaty texture and rich, earthy flavor. They are commonly used in a variety of dishes like:

  • Grilled mushroom caps
  • Stuffed mushrooms
  • Stir-fries
  • Risottos


Although Portobello Mushrooms are mature forms of white button mushrooms, they should not be confused with similar-looking species like Cremini mushrooms, which are essentially younger Portobellos.

How to Sterilize Containers and Growing Substrate for Portobello Mushrooms

Sterilization is a crucial step in mushroom cultivation. Proper sterilization eliminates competing organisms like molds and bacteria, ensuring a clean environment for your Portobello Mushrooms to grow. 

Sterilizing Containers

Submerge the containers in boiling water for 10-15 minutes.

Sterilizing Growing Substrate

  • Wet the substrate to the desired moisture level. Fill it into jars or bags, leaving some air space. Pressure cook at 15 psi for 90 minutes.


  • Place the substrate in a steam sterilizer or a large pot with a tight lid. Steam for at least 2 hours.

Growing Portobello Mushrooms

Propagating Portobello Mushrooms at home is not an easy task and requires patience and perseverance. 

Required Supplies

  • Portobello mushroom spores or mycelium
  • Sterilized compost or manure-based substrate
  • Plastic trays or bags
  • Spray bottle with water
  • Hygrometer and thermometer
  • Gloves and mask for handling
  • Dark room with controlled temperature (55-70°F)

Prepare the Substrate

  1. Sterilization: Sterilize your chosen substrate to eliminate competing microorganisms. This can be done using an autoclave or a pressure cooker.
  2. Cooling: Allow the substrate to cool to room temperature before inoculating it with mushroom spores or mycelium.


  1. Spore Syringe or Mycelium: Inject your substrate with the Portobello spores or mycelium. Wear gloves and a mask to maintain sterility.
  2. Mixing: Mix the substrate and the spores/mycelium thoroughly to distribute the inoculant evenly.

Best Edible Long Stemmed Mushrooms


  1. Set the Conditions: Place the inoculated substrate in a dark room with controlled temperature and humidity. Ideal conditions are 55-70°F and a humidity level of 90-95%.
  2. Monitor: Use a hygrometer and thermometer to monitor conditions. Maintain high humidity by misting the substrate lightly if needed.

Fruiting Stage

  1. Light Exposure: After mycelial networks have fully colonized the substrate, introduce indirect light to trigger the fruiting stage.
  2. Ventilation: Ensure good air exchange during this stage. Stagnant air can lead to mold growth.
  3. Misting: Continue to mist lightly to maintain humidity, but reduce it to around 85-90%.

Container Options to Grow Portobello Mushrooms

1. Growing Bags


  • Easy to sterilize.
  • Good for small spaces.
  • Convenient for beginners.


  • Limited yield.
  • Not reusable.

2. Glass Jars


  • Reusable.
  • Easy to monitor growth.
  • Good for small-scale cultivation.


  • Limited space for mycelium expansion.
  • Risk of glass breakage.

Read the List of Mushroom Types from A-Z here

3. Plastic Tubs


  • Larger yield.
  • Reusable.
  • Easier to manage for bulk cultivation.


  • Takes up more space.
  • Harder to sterilize.

4. Wooden Boxes


  • Natural material beneficial for mycelium.
  • Good for larger yields.
  • Can be used outdoors.


  • Difficult to sterilize.
  • Heavier and less mobile.

Requirements to Grow Portobello Mushrooms

Growing Portobello Mushrooms at home can be a rewarding experience if you follow the right steps and conditions. 


Portobello mushrooms don’t require direct sunlight but do need some light exposure to initiate the fruiting process. 4 to 6 hours of indirect light per day is often recommended.

Pro Tip: Blue or green spectrum light bulbs can be used too.

Growing Substrate

The pH should be between 6.0 and 7.0 for optimal growth. Use this mix:

  • 4 parts organic compost
  • 1 part vermiculite
  • 1 part brown rice flour

In a large mixing bowl, combine the organic compost, vermiculite, and brown rice flour.

Note: The substrate must be sterilized to kill any competing organisms before introducing mushroom spores or mycelium.


Light misting with a spray bottle helps maintain the right moisture level. Overwatering can lead to mold growth. Also, do not let the growing substrate dry completely, so keep an eye on the moisture levels.

Additional Tips to Grow Portobello Mushrooms

  • Maintain a high humidity level, around 95% to 98%, especially during the fruiting stage.
  • Adequate air circulation is necessary to keep the growing area free from mold and bacteria.
  • Serilize the growing medium in an oven or pressure cooker to eliminate competing organisms.
  • Mushrooms don’t benefit from the kind of fertilizers commonly used in gardening. Adding fertilizers can actually disturb the delicate balance of the growing medium and hinder mushroom development.

Here are some Vegetables You Can Plant in August and Harvest in September

Harvesting and Storing Portobello Mushrooms

Portobello Mushrooms 2

Knowing the right time to harvest Portobello mushrooms can make all the difference in flavor and texture. 

  • Harvest when the cap has started to flatten but is not fully opened. This is often the point where Portobellos offer the best flavor and texture.
  • Pay attention to the edges of the mushroom caps. When they begin to uncurl or lift away from the stem, it’s often an indicator that the mushroom is ready for harvest.
  • Portobello mushrooms can get quite large, but bigger doesn’t always mean better. Overgrown mushrooms may lose flavor and tenderness.
  • When the gills under the cap are visible but haven’t turned dark, it’s a good time to harvest. Dark gills often indicate that the mushroom is about to release its spores, making it less desirable for consumption.

Stem Thickness

A firm, stout stem usually indicates that the mushroom is healthy and ready for harvest. Mushrooms with thin, weak stems are often not mature enough.


The cap should have a consistent, rich brown color without any spots of discoloration, which could indicate that the mushroom is past its prime.


  • Harvest the mushroom by gently twisting it off at the base of the stem. Avoid pulling, as that can damage the mycelium and future production.
  • If preferred, you can also use a sharp knife to cut the mushroom at the base, leaving as little stem as possible in the substrate.

Portobello Mushrooms Nutrition Facts

Portobello mushrooms are not only delicious but also packed with nutrients, making them a healthy addition to your diet. Below are the nutritional facts based on a serving size of one cup of grilled Portobello mushrooms, which is approximately 121 grams.


35 kcal


3.9 grams

Total Fat

0.6 grams


5.9 grams

Dietary Fiber

1.7 grams


2.6 grams

Vitamin D

0.2 mcg (1% DV)


17 mcg (4% DV)


5.7 mg (36% DV)


0.4 mg (31% DV)


0.1 mg (8% DV)

Vitamin B6

0.1 mg (6% DV)


428 mg (9% DV)


82 mg (7% DV)


9.1 mcg (17% DV)


0.3 mg (33% DV)


17 mg (4% DV)


0.6 mg (5% DV)


11 mg (<1% DV)

Health Benefits

  1. Low in Calories: Excellent for weight management.
  2. Rich in Protein: Good source of plant-based protein.
  3. High in Fiber: Helps in digestion and maintaining gut health.
  4. Minerals and Vitamins: Packed with essential minerals and B vitamins that support metabolism and nervous system function.


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