Portobello mushrooms are the mature form of the Agaricus bisporus fungus that are known for their savory flavor and hearty, meat-like texture. If you want your own supply of tasty portobellos, they’re easy to grow. Just fill a container with compost, sprinkle on the mushroom spores, and keep the soil moist. Then, set the container in a cool, dark spot. Keep reading below to learn how to grow portobello mushrooms indoors and outdoors and when to harvest them!
The Best Way to Grow Portobellos
Fill a container with manure compost and sprinkle mushroom spores on top. Then, set it in a cool, dark spot that stays between 50-70°F (10-21°C). Mist the soil daily with water and cover with peat moss when mycelium forms. Harvest the shrooms when the caps grow 4-6 in (10-15 cm) wide.
Steps
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Fill a container with a 6 in (15 cm) layer of manure-based compost . Find a growing pot or container that’s 8 in (20 cm) deep and at least 6 in (15 cm) long. Then, pour in a bag of manure-based compost until it’s about 6 in (15 cm) deep. This leaves enough space to mix in more soil and peat moss later. [1] X Research source
- The manure compost is dried, so it shouldn’t stink up your house. However, you may try other organic compost products in place of manure-based compost.
- If you don’t have a container on hand, build your own planter box using scrap wood. Simply nail the wood pieces together to form the bed.
- As an alternative, purchase a portobello mushroom-growing kit . It has all the components you need for growing mushrooms, including a container.
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Cover the bed with black plastic if you're growing portobellos outdoors. To sterilize the soil, lay a piece of cardboard over the compost. Then, cover the cardboard with a single layer of black plastic sheeting . Make sure it’s tight inside the bed and won’t get blown away by the wind. [2] X Research source
- If you’re growing portobellos indoors, sterilizing the soil isn’t necessary. However, you can still do it to help ensure your mushrooms grow big and healthy.
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Leave the bed in the sunlight for 2 weeks if you're growing outdoors. Leave the black plastic sheet in place and let the bed sit outside in the sun. The sunlight passes through the plastic and cardboard, clearing the compost of harmful bacteria that can damage the mushrooms. [3] X Research source
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Mix portobello mushroom spores into the compost. Put on a pair of rubber gloves and sprinkle the spores on top of the compost. Then, gently mix them about 1 in (2.5 cm) deep into the compost. Press down on the compost when you’re finished mixing. [4] X Research source
- Some garden stores carry mushroom spores.
- If you covered the container with cardboard and plastic, remove the pieces and then mix in the spores.
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Mist the spores with water to moisten the soil. Portobello mushrooms need a lot of moisture and humidity to grow. Simply fill a spray bottle with water and mist the compost so it is moist but not soaking wet. [5] X Research source
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Place the container in a cool, dark room if you're growing indoors. Set the mushroom container in a spot that stays cool and dark, like a shed, closet, or basement. Make sure the place you choose stays between 65 to 70 °F (18 to 21 °C). [6] X Research source
- Monitor the soil temperature by placing a soil thermometer in the compost.
- Place a sheet of opaque plastic on top of the container if you don’t have a room that stays dark.
- If the room is too cold, place a heating mat under the container. Maintain the temperature around 65 to 70 °F (18 to 21 °C) to ensure it doesn’t exceed 80 °F (27 °C), as this can damage the growing mushrooms. [7] X Trustworthy Source Penn State Extension Educational organization dedicated to delivering science-based information to people, businesses, and communities Go to source
- The great part about growing mushrooms indoors is that you can grow them year-round.
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Set the container in a shady cool spot if you're growing outdoors. For portobello mushrooms to grow outdoors, the temperature needs to be no higher than 70 °F (21 °C) in the daytime and no lower than 50 °F (10 °C) at night. Simply find a spot in your garden that receives partial sun, like in an area that gets shade from your house, a bush, or a tree. [8] X Research source
- Place a soil thermometer in the container to monitor the soil’s temperature.
- If you don’t have a spot outdoors that stays shaded, set a sheet of opaque plastic on top of the container.
- Choose a spot that doesn’t get soaked with water. While mushrooms like to stay moist, they don’t like to be soaked.
- If the temperatures go beyond the 50 to 70 °F (10 to 21 °C) range, move your container indoors.
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Mist the soil twice daily to keep it moist and to boost humidity. Simply give the compost a spray in the morning and night to ensure the soil is damp. [9] X Research source Keep the humidity in the container between 60 to 70%. To monitor the humidity levels, use a hydrometer . [10] X Research source
- If you’re growing the mushrooms indoors, place a humidifier in the room to keep the humidity level up.
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Cover the soil with peat moss and newspaper when mycelium grows. After about 2 to 3 weeks, you should start to see mycelium covering the compost. This is a white, web-like substance that acts as the mushrooms’ roots. [11] X Research source Just grab some peat moss and spread a 1 in (2.5 cm) layer over the compost. Then, add a single layer of newspaper on top of the peat moss. [12] X Research source
- The peat moss and newspaper help keep the compost moist, encouraging the mushrooms to grow.
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Mist the newspaper daily to keep it moist. Use a spray bottle at least once a day to keep the newspaper damp. This helps keep up the humidity level in the bed and ensures the mushrooms grow and thrive. [13] X Research source
- If you’re growing outdoors, mist the newspaper twice a day.
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Remove the newspaper when you see mushrooms growing. Lift the newspaper after 1 week passes and look for tiny, white heads coming out of the peat moss. If you see any mushroom growth, completely remove the newspaper. [14] X Research source
- If you don’t see any white heads, keep the newspaper on. Check on the mushrooms every few days and remove the newspaper when you see growth.
- It can take between 1 to 2 weeks for the heads to poke out of the moss.
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Continue misting the mushrooms daily as they grow. Spray the peat moss with water every day so the mushrooms stay moist and humid. Each day, the mushrooms should grow taller and their caps should expand in diameter. [15] X Research source
- Be patient, as it can take 1 to 2 weeks for the mushrooms to grow.
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Pick the mushrooms when the caps are 4-6 in (10-15 cm) wide. Portobello mushrooms reach their peak when the mushroom caps completely separate from the stem, open up, turn brown, and are about 4 to 6 in (10 to 15 cm) in diameter. To harvest them, cut the cap off from the stem with a sharp, clean knife or pair of scissors. [16] X Research source
- Alternatively, grip the mushroom just underneath the cap and twist it to harvest it.
- Harvest the mushrooms sooner if you want button or cremini mushrooms:
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Keep moistening the compost until new mushrooms grow. Mushrooms will continue to grow in your container as long as the compost is rich in nutrients. So, keep spraying the container with water daily until a new layer of mycelium forms. Then, add another layer of newspaper and wait for more mushrooms to grow. [19] X Research source
- You typically get 2 to 3 batches of mushrooms out of 1 tray before the mushrooms use up all the nutrients in the compost.
Expert Q&A
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QuestionHow do you get spores from mushrooms?Maggie Moran is a Professional Gardener in Pennsylvania.The process works the best with gilled mushrooms. To create a spore print, cut off the stalk of a fresh mushroom and lay the gill side down in a glass container and cover. Allow 6-12 hours for spores to be released and collect them from the glass.
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QuestionCan you grow portobello mushrooms at home?Maggie Moran is a Professional Gardener in Pennsylvania.Yes, actually mushrooms grow the best inside. Obtain mushroom spores and a growing tray. Fill the tray with compost materials and sprinkle approx 2 cups of spores on the top. Keep the tray moist and in the dark.
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QuestionWhat are the best mushrooms to grow?Maggie Moran is a Professional Gardener in Pennsylvania.While many types of mushrooms are relatively easy to grow on your own, button mushrooms are widely accepted as a wonderful beginning plant.
Tips
- Portobello mushrooms are the mature form of the Agaricus bisporus fungus. Button mushrooms (also called white mushrooms) are the white, immature form of Agaricus bisporus while cremini mushrooms (also called baby bellas) are the brown, immature form. [20] X Research sourceThanks
- Portobello mushrooms are low in calories, fat, and sodium. They are also a great source of vitamins and minerals like selenium, potassium, and vitamin B2. [21] X Trustworthy Source Penn State Extension Educational organization dedicated to delivering science-based information to people, businesses, and communities Go to sourceThanks
- Cook your portobello mushrooms by roasting, grilling, or sautéing them. Or, enjoy them raw or on top of pizzas, salads, and more.Thanks
Things You’ll Need
- Growing container that’s at least 8 in (20 cm) deep
- Manure-based compost
- Cardboard, optional
- Black plastic sheeting , optional
- Portobello mushroom spores
- Spray bottle
- Soil thermometer , optional
- Opaque plastic , optional
- Heating mat , optional
- Hydrometer , optional
- Peat moss
- Newspaper
- Sharp knife or scissors
References
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://extension.umn.edu/planting-and-growing-guides/solarization-occultation
- ↑ https://extension.umn.edu/planting-and-growing-guides/solarization-occultation
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://ecommons.cornell.edu/server/api/core/bitstreams/ab0d7e54-ebf8-45e5-9aee-7ba9eb011875/content
- ↑ https://extension.psu.edu/seeding-substrate-and-management-of-growing-agaricus-bisporus
- ↑ https://www.mushroom-corner.com/posts/how-to-grow-button-mushrooms
- ↑ https://ecommons.cornell.edu/server/api/core/bitstreams/ab0d7e54-ebf8-45e5-9aee-7ba9eb011875/content
- ↑ https://mushroomgrowing.co.uk/how-to-grow-portabello-mushrooms-at-home/
- ↑ https://ecommons.cornell.edu/server/api/core/bitstreams/ab0d7e54-ebf8-45e5-9aee-7ba9eb011875/content
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://ecommons.cornell.edu/server/api/core/bitstreams/ab0d7e54-ebf8-45e5-9aee-7ba9eb011875/content
- ↑ https://garden.org/learn/articles/view/4100/Growing-Mushrooms/
- ↑ https://www.mushroom-corner.com/posts/how-to-grow-button-mushrooms
- ↑ https://www.britannica.com/topic/portobello-mushroom
- ↑ https://ecommons.cornell.edu/server/api/core/bitstreams/ab0d7e54-ebf8-45e5-9aee-7ba9eb011875/content
- ↑ https://www.britannica.com/topic/portobello-mushroom
- ↑ https://extension.psu.edu/six-steps-to-mushroom-farming
About This Article
You can grow portobello mushrooms indoors or outdoors, and it should only take you a few weeks. To get started, you’ll need a wooden box to grow the mushrooms in. Fill the box with a layer of manure-based compost, and cover it with a piece of cardboard and a layer of black plastic sheeting. Leave the box outdoors for 2 weeks so the sunlight can kill any bacteria. Then, move it into the shade or indoors where the temperature will stay below 70 degrees Fahrenheit. Mix your spores into the compost, and cover it with peat moss and a layer of newspaper. Mist the newspaper with water once or twice a day, and in a couple of weeks you should start to see the mushroom heads peeking out of the soil. For more tips from our Gardening co-author, including how to harvest your Portobello mushrooms, read on!
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