How to Grow Portobello Mushrooms (6 Easy Steps!)

Are you looking to begin growing delicious portobello mushrooms at home, but you don’t quite know how or where to get started? The good news is it isn’t difficult or terribly expensive, and you only need a few supplies to get your mushroom crop going. Note: If you click some of the links in this article we may earn a small commission at no additional cost to you.

How to Grow Portobello Mushrooms

Step 1 – Get a Large Container and portobello spores

When growing a larger species of mushrooms like portobellos, you need a sufficiently sized spot to plant and grow them, such as a large plastic under-bed storage container – at least four feet by four feet – as well as compost, peat moss, and newspaper.

Step 2 – Add prepared compost and spores or spawn

Fill your container with compost at a depth of six inches, sprinkle with your spores, and gently tamp the mixture down.
Note – in the video below they show you how to take a spore print and grow directly from store bought mushrooms. This is a slightly more advanced technique. We recommend you start with a kit, then start from spawn, then use this spore technique last after you are comfortable with the easier methods.
100 Grams of Portobello Mushroom Spawn Mycelium to Grow Gourmet Mushrooms at Home or commercially - G1 or G2 Spawn

Step 3 – Store in a dark room

Your growing container should stay in a dark room or cabinet that you can keep between 65 and 70 degrees Fahrenheit until you begin to see white growth across the surface, then spread a layer of dampened peat moss over the top.

Step 4 – Keep covered with moist newspaper or moss

Cover the container with newspaper and mist water over the top twice a day for two weeks before you look underneath the paper to check in on your portobellos.

Step 5 – Mist daily when mushroom heads appear

When you can see tiny white mushroom heads, you can remove the paper and then mist it with water daily. If you don’t have mushroom heads yet, leave the newspaper on and continue misting twice daily for one more week.

Step 6 – Harvest

Harvest to suit your preference in size – you don’t have to wait until your mushrooms are the size of your hand to pick and enjoy them. Since you can closely control the temperature indoors, you can grow portobello mushrooms year-round. Check out the video below on easy ways to grow mushrooms at home. The video uses cremini mushrooms; however, Portabello mushrooms are just slightly older button mushrooms and cremini are simply the brown version of button mushrooms.

How Difficult Is It to Grow Portobellos?

While the popular belief is that growing mushrooms is incredibly difficult and time-consuming, portobellos are not only easy to grow, they’re also robust enough that you can grow your crops inside or outside. All it takes are interest, patience, and the supplies to grow beautiful mushrooms.

Acquiring Supplies

While you can go to the hardware store and garden supply to obtain all of the items needed to grow portobellos, you don’t necessarily have to. There are several websites out there that assemble kits containing everything you need to start growing right away. The fastest way to grow portobello at home is to use one of these starter kits from Mushroom Adventures. You’ll simply mist daily till it grows. What you’re buying is mushroom compost that is fully grown with portobello spawn. All you need to do is water and wait. Once you get comfortable with that move on to making your own mushroom compost then innoculate it with either a portobello mushroom spawn or a portobello spore syringe. Click either of the pictures below to check the current price for these things on Amazon.
Gourmet and Medicinal Mushroom Cultures (Portobello Mushroom (Agaricus bisporus))
  • 10cc - 1st Generation Mother Culture for Mushroom Cultivation
  • A Very Large Selection of Mushroom Cultures to Choose From
  • Grow Your Own Mushrooms at Home
  • Mushroom Cultures can be Stored for Over One Year from Arrival
  • Grown and Harvested in a Professional Mycology Laboratory

An Investment of Time

Mushrooms’ growth period doesn’t typically take a long time – portobellos, for example, take only a couple of weeks from the time you put spores in the growing material to harvest time. Aside from waiting for your mushrooms to grow, the most time you’ll spend is gathering supplies and getting everything ready.

Companion Crops for Portobello Mushrooms

Companion crops are two or more plants that grow well together for any reason, such as pest control, pollination, or simply maximizing space. If you are looking to grow mushrooms in your vegetable garden, they grow well with perennials like asparagus and Jerusalem artichokes. Since mushrooms grow well in shade, they can also be planted beneath trees that provide heavy shade all day, provided you are in a temperate climate. Just make certain to keep them moist and safe from animals that may be tempted to dig.

Don’t Go It Alone

While growing mushrooms seems like an incredible niche pastime, there is an enormous community of amateur mushroom growers out there, especially if you look online. By connecting with others, you can get tips you might never have thought of, celebrate successes, and have a shoulder to cry on just in case you have the trouble of one sort or another with your crops.

Is Growing Portobellos Expensive?

Getting started growing your own portobello mushrooms at home isn’t at all expensive. The basic supplies are quite cheap, and chances are high that you can obtain everything locally. Be careful buying supplies online, as some specialized mushroom supply sites do put a higher price on equipment that they claim you absolutely must-have. Amateur home growing of mushrooms requires very little, and you shouldn’t have to spend an arm and a leg to get started. The mushroom grower in this video takes you through the entire process performed via one method. She shows everything from preparing the portobellos for making spore prints, to creating a growing container.

Getting Serious

If you enjoy growing mushrooms once you get started, you might consider becoming more serious about it by selling them to local shops or at your farmer’s market. Buy a good book on mushroom cultivation, explore other growing techniques, and have a chat with other mushroom farmers to expand your horizons. You could also think about getting in touch with professional mushroom farmers for advice and tips. Most farmers are happy to help, many of them have started right where you are in the beginning.

How To Grow Portobello Mushrooms on Coffee Grounds

First, you’ll want to make sure you have enough grounds for the weight you’re working with. Consider using a mixture of 70 percent grounds, 20 percent sawdust pellets or straw, and 10 percent mushroom spawn. Try following these steps to build a successful mushroom garden:
  1. Disinfect the growing area to prevent the spread of bacteria
  2. Boil your straw or sawdust at 170°F to kill any organisms in it, then use a salad strainer to get the loose water out
  3. Mix coffee grounds with straw, sawdust, or another substrate
  4. Pull out any clumps
  5. Break up your mushroom spawn and add it
  6. Dump the mixture into a cleaned container
  7. Seal it with a twist tie after burping out all the air
  8. Poke a few holes in the bottom for air
  9. Place the container in a humid area around 65-75°F
  10. Periodically increase the size of the holes
  11. Move the container into an area with a slight bit of light once the mushrooms start to grow
  12. Sprinkle them with moisture occasionally, but never use enough to cause mold to grow
Most people will want to use a dedicated clean plastic bag as a container.

FAQ

Can you grow portobello mushrooms in coffee grounds?

Coffee grounds are an excellent growing material for homegrown mushrooms including portobellos. The grounds need to be pasteurized which you can do at home with boiling water. Then you mix them with sawdust or straw to make an ideal growing substrate for portobello. See the full instructions above.

Are button mushrooms and portobello the same?

Portobellos, button mushrooms and cremini mushrooms are all the same species. The only difference is usually the size they are harvested at and the names they are sold under to differentiate those sizes.

Are mushrooms good for your health?

Like most edible plants, mushrooms do have some great health benefits. If you enjoy them, rest assured that they are a wonderful addition to a healthy diet. Mushrooms are chock full of niacin, riboflavin, and pantothenic acid, which are good for your heart. Niacin keeps your nervous system working properly, riboflavin breaks down food into components your cells can use, and pantothenic acid helps your body to convert your food into energy.