• The liquid culture syringes are between 10 and 12cc and are ready to inject to your substrate of choice such as sterilized rye berries.
  • Our cultures are made by experts and are 100% clean and viable.

Grow your own edible and medicinal portobello mushrooms with liquid culture syringes!

Agaricus bisporus, more commonly known as portobello mushroom or the common mushroom, is native to the grasslands of Europe and North America. When immature, Agaricus bisporus is the small button mushroom that we commonly see in stores. It can either be white or brown when immature and is known as the portobello when mature. One of the most widely consumed mushrooms, it is cultivated in more than seventy countries worldwide. It is rich in nutrients, containing B vitamins such as riboflavin, niacin and pantothenic acid, as well as phosphorus, potassium, copper, selenium and proteins. With its high nutritional value, there are many health benefits to consuming Agaricus bisporus.

  • Antioxidant*
  • Energy boost*
  • Supports the cardiovascular system*
  • Detoxify the body*

Agaricus bisporus’ cap grows in a hemispherical shape until it flattens out at maturity. It is 5-10cm in diameter with either a white or brown colored cap. It can be grown on a mix of compost and manure and needs to be kept in the dark. It likes a lot of humidity but should not be directly sprayed on.

OutGrow® is proud to present a full line of edible and medicinal mushroom cultures. Economically priced so that everyone can enjoy the wonderful hobby and benefits of mushroom cultivation. Our cultures are made by experts and are 100% clean and viable.

The liquid culture syringes are between 10 and 12cc and are ready to inject to your substrate of choice such as sterilized rye berries.

*This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

Agaricus bisporus Facts

Agaricus bisporus is an edible mushroom originally grown in North America and Europe and commercially grown in over 70 countries worldwide. It’s known as white mushroom or Swiss brown mushroom when immature. When it's fully grown and ready for harvest, the mushroom develops a brown cap measuring 5-10 centimeters. Mushroom growers in different parts of the world sell it under different names, but Portobello mushroom is the most common name.

Agaricus bisporus accounts for approximately 90% of mushroom production in the United States but less than 40% of the world's output. The yearly value of the mushroom crop in the United States is more than $800 million. The per capita consumption of fresh mushrooms is approximately 1 kg per year in the United States.

How to Identify Agaricus bisporus

There are many ways to identify an Agaricus bisporus. The following are core qualities that define a genuine Portobello mushroom.

  • Cap: During the initial growth stages, an Agaricus bisporus has a white, hemispherical cap. It then develops into a brown convex shape before it flattens up once it has matured. The cap diameter of a mature Portobello mushroom ranges from 5-10 centimeters.
  • Gills: The mushroom has narrow and free-crowded white gills. The gills are pink in the early stages, reddish in their middle growth stage, and chocolate brown in the full-grown stage.
  • Stem: Its stem is 1-2.5 centimeters thick and 2-7 centimeters thick. It’s often bald with miniature scales, turns white and reddish over time, and then brownish after it has matured.
  • Taste/odor: Pleasant and earthy.
  • Growth season: They grow from the late spring months to autumn.
  • Basidia: Bisporus, or two-spored.
  • Spore print: They are usually deep chocolate brown.
  • Habitat/ecology: The mushrooms grow well in grassy areas, near horse manure piles, and areas with favorable conditions. They are fruitful all-year round, excluding mid-winter, provided they get adequate moisture supply.

How to Grow Agaricus bisporus

The mushroom mycelium growth method varies from the methods used to grow other mushrooms. As a secondary decomposer, the raw materials of Agaricus bisporus have to be broken down by fungi and bacteria to initiate growth. The process of breaking down Agaricus raw materials is known as composting. These mushrooms are grown commercially around the world, though the best growers are in the United States.

Phase 1

  • Add compost ingredients, water and mix them up. Turn the pile daily for two weeks until the straw becomes soft.
  • Compress your compost, and then add manure and gypsum to prevent the straw from sticking together.
  • Add enough nitrogen supplements and water while keeping temperatures above 155-degrees Fahrenheit.

Phase 2

  • Spread and cool the pile to initiate the pasteurization process.
  • Put your compost in plastic sleeves and raise the temperature to 140 degrees.
  • Ventilate the sleeves long enough until you can’t smell the ammonia.


  • Sprinkle the spawn over the compost surface.
  • Keep the growing tray in a safe room, keeping the room temperature at 75 to 77-degrees Fahrenheit.
  • Add slow-release soybean supplement to boost the growth of the spawns.


  • Cover your colonized compost using a uniform 2-inch layer.
  • Keep the growing room dark, and keep the room humidity levels high.

Pinning and Cropping

  • Reduce the room temperature to around 60 to 66-degrees Fahrenheit, and don’t reduce the humidity.
  • After three weeks of casing, harvest your mushrooms.

Tips on Cooking This Mushroom

After harvesting your fresh mushrooms, you can mix them with many dishes. You can sauté them and mix them into pasta. You can prepare pizza mushrooms, curried mushrooms, white wine and garlic Agaricus bisporus, mushroom marinara ravioli, stuffed mushrooms, and more.