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How to Grow Portobello Mushrooms at Home (2024 Guide)

Want to know how to grow portobello mushrooms yourself? They aren’t just a tasty and nutritious food, they’re also easy to grow at home!

Here’s a useful guide that gives you everything you need to know about growing mushrooms at home, indoors and outdoors.


How To Grow Portobello Mushroom at Home
how to grow portobello mushrooms at home indoors

What Are Portobello Mushrooms?

Portobello mushrooms are from the Agricus family and are indigenous to the grasslands of Europe and North America.

They are cultivated in over 70 countries around the world, making them one of the most widely eaten mushrooms on the market!

They are easy to identify too, with rounded shape, brown circular cap and near-black gills underneath.

They’re one of the most versatile and delicious mushrooms you can grow, with a meaty, succulent flesh that makes them an ideal ingredient for everything from vegetarian burger patties to pasta dishes, sauces, stuffing and even as mushroom steaks for the grill.

Growing Portobello Mushrooms

Now that you know why these mushrooms are so great, let’s talk about how to grow mushrooms at home. Essentially, there are two methods for growing portobello mushrooms.

You can grow them indoors in a dark room or cupboard or you can grow them outside as part of your vegetable garden. All you need is a mushroom growing kit, which you can either purchase online through Amazon or make yourself, and you can start growing mushrooms at home

how to grow portobello mushrooms at home indoors


How to Grow Portobello Mushrooms Indoors

Let’s start with the indoor method of growing portobello mushrooms at home. This method is highly recommended if you live in a colder climate or have limited outdoor space.

It’s the preferred choice for most people as it means you can control the climate and grow mushrooms all year round.

Materials Needed

To make your mushroom growing kit, get some old newspaper, peat moss, compost and a tray that is about 4 x 4 feet and 8 inches deep.

Alternatively you can purchase portobello mushroom grow boxes at Amazon and other online retailers now. Which takes out a lot of the hassle and is easy and clean.

Growing kit for portobello mushrooms in a box at home

via Amazon

Filling with Compost

best fertilizer for growing portobello mushrooms at home


After you have selected a try, fill it up with seasoned manure compost from your local nursery. Once the tray is fairly full, mix the portobello mushroom spores with a handful of compost and sprinkle it onto the tray, tamping it all down lightly.

Then place the tray somewhere dark and wait until you start to see the spores begin to grow, which looks like a white, filmy web. Keep the temperature at about 60-70 degrees F.

Adding Peat Moss

adding peat moss for growing portobello mushrooms at home


Take a layer of peat moss (you can purchase it here on Amazon) and place it over your tray, covering it with newspaper. You need to mist the newspaper with distilled water twice a day for a few weeks.

Check on the progress of your portobello mushrooms regularly and when you start to see mushroom heads, you can remove the newspaper permanently. Once your newspaper is removed, continue to mist the try each day.

Harvesting Portobello Mushrooms

Your mushrooms are ready to harvest as soon as they reach the right size for your needs. Continue misting them each day until you are ready to harvest them.

It’s best to harvest them when the caps are still a little curved downwards rather than flat in shape. They will reach full size when they are 4-6 inches in diameter. 

Growing and Harvesting Portobello Mushrooms at home


How to Grow Portobello Mushroom Outdoors

You can grow these mushrooms outdoors as long as the temperature stays between 60-70 degrees F and you can keep them in a shaded area. Many people choose to grow mushrooms at home in a raised bed because it’s easy to set up and harvest.

Growing in a Raised Garden Bed

Create a raised bed measuring approximately 4 x 4 feet and 8 inches deep. You can use logs, wood, bricks or concrete blocks to create the walls of your bed.

Fill the bed with mature compost to at least 6 inches deep and cover the bed with black plastic for 2 weeks. This sterilizes the bed, helping to get rid of any bacteria that can damage your crop.

Read more: 50+ Expert Tips on DIY Raised Garden Beds

Sprinkling Your Portobello Mushroom Spores

Remove the plastic from your raised bed and mix the portobello mushroom spores with a handful or two of the compost from the bed.

Sprinkle the spores and compost evenly over the bed. Leave the bed alone and watch for the white, filmy web of the spores to start showing.

Get your portobello mushrooms spores here

Below is growing portobello mushrooms in pots inside a greenhouse.

Growing portobello mushroom outdoors in a greenhouse


Adding Peat Moss

As with the indoor method, place a layer of peat moss over your bed and cover it with newspaper once the spores are growing.

Mist the newspaper with distilled water twice a day, every day for 10 days to keep the growing portobello mushroom spores damp.

Don’t let the soil get too wet however, as this can lead to your beds becoming a mosquito breeding ground. If mosquitoes do get out of hand, look at these mosquito control options.

Once you see that the heads of your mushrooms have started to develop, you can remove the newspaper and continue to mist them with water as they grow.

Harvesting Outdoor Portobello Mushrooms

You can harvest your mushrooms as soon as they reach the size you need, but they are best harvested when they reach about 5 inches in diameter.

These mushrooms grow quickly, so you can get about 3 batches of mushrooms over 2-3 weeks as they grow before you’ll need a new supply of spores.

It’s important to only pick whole, firm portobello mushrooms for use in the kitchen. Avoid any mushrooms that are decayed, soft and wrinkled, or damaged by birds or insects.

Portobello Mushrooms Nutritional Value


Portobellos are rich in Vitamin B, Niacin and Riboflavin, which help support the functioning of your body’s cells by converting food into energy.

Creating healthy blood cells and maintaining the health of your hair, skin, nails and organs.

These vitamins are also vital for supporting your brain function and overall good health, so it’s important to include foods rich in these vitamins in your daily diet.


Portobello mushrooms are an important source of protein, providing 4.3g of protein per 100gs.

Protein is key to muscle and cell health, providing the building blocks for a healthy body brain, and portobello mushrooms are a good source of this nutrient, especially if you follow a vegetarian or vegan diet.


Eating these mushrooms also supplies your body with a range of important minerals that are essential for a healthy and functioning body, including magnesium, zinc, iron, manganese, potassium, phosphorus, selenium and copper.

All of these trace minerals keep our organs and brains healthy, support our immune systems and help prevent disease.

Growing portobello mushrooms at home


Fiber is essential for our digestive health, keeping blood sugar and cholesterol levels within healthy parameters and reducing our risks of diabetes, heart disease and bowel cancer.

We should each get about 20-30g of fiber per day, and portobello mushrooms are a great source!

Portobello Mushroom Calories

Portobello mushrooms are a good source of healthy carbohydrates that will fuel your body through the day.

They’re also a great food to include in your diet if you are trying to reduce your weight because 100g of mushrooms equals just 35 calories. This is because they are fat free, cholesterol free and have very little sodium. They’re the ideal diet food!

Above are the nutrients that you can get from consuming this type of mushroom and the reason why more and more people are wondering how to grow their own portobello mushrooms at home.

Start Growing Portobello Mushrooms in Your Home

Now you know how to grow portobello mushrooms! As you can see, it’s easy to grow portobello mushrooms at home, creating your very own, homemade feast to enjoy!

About the Author Ann Katelyn

I'm Ann Katelyn, Creator and Chief Author of Sumo Gardener. Since I was a child I've always been fascinated with plants and gardens, and as an adult this has developed into my most loved hobby. I have dedicated most of my life to gardening and started Sumo Gardener as a way to express my knowledge about gardening with the hope of helping other people's gardens thrive.

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1 comment
StankyDanky says March 17, 2020

Very helpful information! I will be sure to try this.

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