How To Grow Portobello Mushrooms The Right Way

Last updated: 07/10/20

Food enthusiasts, like me, who have a soft spot for mushrooms and have tasted virtually all the popular and edible types, should be able to testify to the fact that portobello mushrooms are delicious. 

They have a rich, meaty, and earthy flavor that you’d love to always have in your sandwiches, soups, and salads.

For me, I love growing my mushrooms indoors. They are an all-important addition to my meals, which is why I need to be able to easily access them without having to go to a store, 1 or 2 miles away from my home.

If you’d like to know how to grow portobello mushrooms, then this article is all you need to get started.

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How to Grow Portobello Mushrooms

To grow portobello mushrooms indoors and outdoors, you can follow these tips.  We have a more detailed step by step guide below:

  • Prepare a growing space, i.e., where you’d like to grow your delicious mushrooms. If you’re growing outdoors, make sure they’re safe and protected from farm pests and rodents.
  • Prepare your growing materials. You’ll need a container filled with manure composts that the mushrooms will depend on for food and energy as they grow.
  • If you’re growing outdoors, you might want to sterilize all your materials; the container and compost would need to be sterilized.
  • Cover the manure compost in your growing tray with the spores which you’d have purchased, and prepared for this purpose. 
  • Mix the spores properly with the compost.
growing portobello mushrooms at home
  • Spray the surface of the compost with water to keep moist.
  • Cover your growing tray with newspapers or with a cloth to retain the moisture.
  • Spray the newspaper or cloth regularly for about 2 weeks, until the white buttons of the mushrooms begin to appear.
  • Once the mushrooms are all out and there are no visible white web-like streaks in the soil, you can then uncover and continue to spray until the mushrooms mature.
  • Leave for 2 more weeks for the caps to unfurl.
  • Harvest by picking with your bare hands.
  • Cook in your meals and serve!

How Do You Grow Portobello Mushrooms at Home?

Portobello, sometimes referred to as portobello, mushrooms were not so popular in the past. However, over the past few years, they have continued to grow in popularity.

This increase might largely be due to the way these delicious adult criminis can successfully retain their heavy nutrients and intense flavor for long, even after they’ve been cooked or stored for a long time.

Portobello mushrooms are also known for their health benefits. They’re said to contain nutritious properties like minerals, vitamins, sterols, and so on, that help boost our immune system, fight inflammation, as well as the development of cancer, in the body.

So, how can you grow your own mushrooms at home? The following steps will help you from start through to the time they’re ready for harvest.

STEP 1: Choose Your Grow Area

The first step, if you want to be able to grow your mushrooms without the stress of worrying over temperature, humidity, and other environmental conditions, is to find your babies a perfect growing area.

Make sure your grow space is spacious enough to accommodate the quantity you’d want to grow. 

Be sure to also confirm that your mushrooms will not be exposed to intense heat or sunlight, as they do not really need the sun for their growth.

Step 2: Prepare Your Planting Medium​

The next step is to prepare the planting medium(s) you’d like to use.

One quite important thing to note, when growing larger types of mushrooms like the port​obell​o, is that you’ll need a lot of space. Your planting medium shouldn’t be less than 8 inches deep and 6 inches long.

Whether you decide to build a portable planting medium or purchase one for yourself online, you have to ensure it is going to be comfortable for you and your mushrooms as they grow.

Step 3: Prepare Your Other Planting Materials

Mushrooms are unlike plants in their biology, they do not process their food on their own like the plants typically do through photosynthesis.

Mushrooms are fungi. They need to directly depend on another source for the nutrients they need to survive, which is why you need mixed, dried manure-based composites, fertilizers, and other growing materials.

These materials will help in starting and growing your mushrooms in the best way possible, right from the beginning until the time they’re completely ready for harvest.

Mushrooms can only grow from spores. So, you’ll also need their spores too. You can easily purchase these online or from gardening stores close to you.

Step 4: Fill Your Planting Medium With The Composite

This may sound quite simple. However, it is one simple step you wouldn’t want to miss out on.

After successfully building or purchasing a growing medium, the next step would be to fill with the manure compost. Make sure to fill them in properly.

If you want to ensure your mushrooms grow big and without any health problems, you may also want to sterilize your planting materials.

You can do this by tightly covering the compost for about 2 weeks or more before going ahead to plant the spores.

However, this is not entirely necessary if you’re growing indoors. What sterilization does is to just reduce the risk of contamination in your mushrooms.

Step 5: Sprinkle Your Mushroom Spores

After filling the compost in, you’d also want to sprinkle your portobello mushroom spores on the compost material.

Mix the spores, properly, with sufficient compost in the bed you’ve prepared. Instead of mixing, you can also cover lightly with peat moss or some more compost material.

Step 6:  Cover With A Newspaper/Cloth

The next thing to do would be to cover the compost with a newspaper or with a cloth to keep your bed moist always.

You’d also have to regularly spray the newspaper or cloth for adequate moisture.

Mushrooms need adequate moisture to grow. So, you might want to keep the humidity in and around your growing bed up by spraying once or twice per day.

Step 7: Remove Newspaper/Cloth

After two weeks, the mushrooms should start shooting out.

You can lift the covering to check for the tiny, white sprouts. If they’re there, then it’s time to remove the covering.

However, if you still notice some white streaks in the compost, leave the newspaper or cloth in place. These white, web-like streaks are an indication that your mushrooms are yet to fully take root in the compost.

Step 8: Keep Spraying Until They’re Fully Mature

When you’re entirely sure the mushrooms are rooted properly, you can then remove the covering you used.

Continue to spray the compost until your mushrooms are grown. This shouldn’t take long—between 10 to 20 days, all things being equal.

You might still want to wait a bit longer for the mushroom caps to fully unfurl if you want the portobellos. They are usually about 1.6–2.4 inches long.

When your portobellos are out, then they should be ready for harvest. And, ultimately, for your consumption!

You can harvest your portobellos early if you want to. However, you’d only be harvesting criminis and not the portobellos you want exactly.

Here is a good video that shows you how to grow in a 5 gallon bucket:

​How Long Does It Take to Grow Portobello Mushrooms?

Portobello mushrooms should not take long, at all, to grow. They should be ready for harvest after about 10–12 days of spawning them.

However, if you harvest them at this stage, you’d only be picking criminis, which are equally delicious, but not as chewy as mature portobellos.

If you want mature portabella mushrooms, you might have to wait a few more weeks (a minimum of two) for them to increase in size. Mushrooms are said to increase to almost double their size in about 24 hours.

So, in all, the cultivation of portobello mushrooms shouldn’t take you more than 6 months. With a mushroom grow kit, it should take you less than that, say 4 weeks.

growing portobello mushrooms

The duration of cultivation should depend entirely on how big you want them to grow. Once you’re satisfied with the size, and it’s not up to 6 weeks yet, you can go ahead to pick and devour your mushrooms however you want. 

Is It Difficult to Grow Portobellos?

Portobellos have been described as the easiest species of mushrooms you can grow, whether indoors or outdoors, using any preferred growing medium and method.

Portobellos are easiest to grow indoors because you wouldn’t have to worry about extreme changes in weather, pests and other issues mushroom farmers are likely to encounter.

To make growing even a lot easier for you, you can use mushroom growing kits that you can easily purchase online. Mushrooms growing kits are handy, and shouldn’t cost you too much. 

Is Growing Portobellos Expensive?

The straight answer is an emphatic, NO.

Portobellos are really not expensive to grow.

All you need is a growing medium (which you can easily build by yourself), adequate water supply, manure compost, mushroom spawns, and a few sheets of newspapers or a piece of cloth. 

And, of course, you need a comfortable growing space in your home too.

The growing materials that might cost you are the spores and the growing kits (which come at a price for no stress at all). Other than these, every other thing you’d need should not be beyond your reach.

Green thumb Gardener occasionally links to product and/or services offered by vendors to assist you with all your gardening needs. Some of these may be affiliate links, meaning we earn a small commission if items are purchased.

Greenthumb Gardener Expert Mushroom Growing BIBLE
mushroom growing for you

Mushroom Growing 4 You

  • Growing Organic, Healthy Gourmet Mushrooms at Home
  • Learn to SELL Mushrooms for Profits
  • Step-by-step PDF guides and videos
  • 60 Day, 100% Money Back Guarantee

Final Thoughts

Now that you already know how to grow portobello mushrooms, you can then go ahead to start making your preparations already. 

Growing port​obell​os is quite easy and not at all expensive. You’ll definitely have fun growing these mushrooms, whether you grow indoors or outdoors. 

So, enjoy farming your mushrooms!

Meanwhile, why haven’t you even started already?

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Related Questions

Where do portobello mushrooms grow?

Portobellos are native to Italy. However, they can grow anywhere, indoors or outdoors, as long as they’re grown under the most comfortable growing conditions.

Can you grow portobello mushrooms in coffee grounds?​

Mushrooms generally depend on other materials like coffee grounds that contain the nutrients they need to survive. So you can.

Green Thumb Gardener
growing portobello mushrooms
Jeremy Starke

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