How To Grow Portobello Mushrooms - Step-by-Step Guide 2023

Written by Ivy

Mar 25 2023

How To Grow Portobello Mushrooms - Step-by-Step Guide 2023

Portobello mushrooms are large, flavorful mushrooms that are commonly used in many different dishes. They are easy to grow and can be a fun and rewarding project for any home gardener. In this article, we will go over the steps involved in growing portobello mushrooms.

How to Grow Portobello Mushrooms?

Step 1: Choose Your Spawn


The first step in growing portobello mushrooms is to obtain the mushroom spawn. Spawn is the vegetative part of the mushroom that will eventually produce the fruiting body (the mushroom). You can purchase mushroom spawn from a variety of sources, including online retailers, garden centers, and specialty mushroom stores.

When choosing your spawn, look for a variety that is suitable for growing portobello mushrooms. You can choose from several types of spawn, including sawdust spawn, grain spawn, and plug spawn. Sawdust spawn is the most common type of spawn and is easy to use.

Step 2: Prepare Your Growing Substrate

Once you have your mushroom spawn, you will need to prepare the growing substrate. The growing substrate is the material that the mushroom will grow on. For portobello mushrooms, the ideal growing substrate is a mixture of composted manure and straw. You can purchase pre-made mushroom compost or make your own by mixing manure and straw together.

Fill a container with the prepared compost, leaving a few inches of space at the top. Moisten the compost until it is damp but not soaked.

Step 3: Inoculate Your Substrate

Next, you will need to inoculate your substrate with the mushroom spawn. To do this, simply spread the spawn over the surface of the compost. You can do this by sprinkling the spawn over the compost, or by mixing it in with a fork or gloved hands.

Once the spawn is evenly distributed over the compost, use a sterilized tool (such as a fork or spatula) to mix the spawn into the compost. Be gentle to avoid damaging the spawn.

Step 4: Cover and Incubate

After you have inoculated your substrate, cover it with a layer of plastic wrap or a lid to keep it moist. The mushrooms will need a humid environment to grow, so be sure to keep the substrate damp but not too wet.

Place the container in a warm, dark location (such as a closet or basement) and let it incubate for 10-14 days. During this time, the spawn will grow and colonize the substrate.

Step 5: Provide Light and Humidity

After the substrate has been colonized by the spawn, remove the cover and place the container in a location with plenty of indirect light. The mushrooms will need about 12-14 hours of light per day.

Mist the substrate with a spray bottle several times a day to keep it moist. You can also place a humidifier nearby to maintain the necessary humidity level (around 80%).


Step 6: Harvest Your Mushrooms

After about a week, you should start to see small white bumps (called primordia) forming on the surface of the substrate. These will eventually grow into mature mushrooms.

Harvest your mushrooms when they reach full size (usually about 4-6 inches in diameter). To harvest, simply twist the mushroom stem gently until it snaps off from the substrate.

Step 7: Repeat the Process

Once you have harvested your mushrooms, you can repeat the process with the same substrate or start over with a new batch of compost. If you are using the same substrate, be sure to sterilize it first to prevent contamination.


Growing portobello mushrooms can be a fun and rewarding project for any home gardener. With the right materials and a little bit of patience, you can grow delicious mushrooms right in your house and enjoy a wonderful dinner!


How Long Does a Portobello Mushroom Take to Grow?

Lift up the newspaper once the two weeks have passed. In the peat moss, keep an eye out for tiny, white heads. Keep the newspaper off if they are there. Indicating the mushrooms are establishing roots are any white streaks in the soil.

Can You Farm Portobello Mushrooms?

You can grow portabella mushrooms on your own, yes. The mushroom spores must still be purchased whether you use a kit or begin the process from scratch.

Where Do Portabella Mushrooms Grow Best?

The Portabella mushroom, also referred to as Agaric cultivé, Champignon Portobello, Flat Chestnut mushroom, and the Cultivated Mushroom, is a type of individual mushroom that grows in grass, close to manure piles, and on leaf litter close to conifers, particularly Monterey cypress trees in the northern hemisphere.