Found in the produce section of your grocery store and in many of your restaurant dishes, the portobello mushroom is a common pick among consumers and chefs alike. Well known for their taste, portobello mushrooms are of the same species as the common button mushroom and are the mature version of the common crimini button mushroom. With the proper materials, growing portobello mushrooms at home can be challenging, but effective. By following these few steps you will be able to successfully propagate your own portobello mushrooms.
Purchase a manure-based compost from your local garden speciality store. Fill a raised bed with the compost to a depth of 7 to 12 inches. Cover the raised bed with black plastic sheeting and allow the covered compost to set in the sun for one full day. The sun will warm and cook the compost, releasing important nutrients.
Remove the black plastic sheeting from the raised bed and distribute the crimini mushroom spores across the surface. You may be able to purchase mushroom spores at a garden speciality store, but they are easier to purchase from an online retailer.
Use a garden rake to completely cover the spores with the loose compost.
Water the covered mushroom spores until thoroughly moistened. Place the black plastic sheeting back over the raised bed.
Remove the plastic sheeting and water the bed once per day and recover the with the plastic. Complete the process daily for one week.
Sprouting should occur after a period of two weeks. Harvest the mushrooms once they reach the desired size.
If the mushroom spores have not sprouted within two to four weeks, the spores that were purchased could have been a bad batch. You can contact the retailer or buy a new set of mushroom spores.