Oyster mushrooms are typically found on wood, but they are easy to grow using just about any type of substrate, including straw. Although you can buy kits to grow oyster mushrooms, you will find that it is just as easy and cheaper to grow them on your own. Oyster mushroom spawn, and indeed most other varieties of mushroom spawn, can be found at garden centers and nurseries.
Fill a large pot with chopped straw. The straw should be roughly chopped in 1- to 3-inch pieces. Pour enough water into the pot to just cover the straw and place it over high heat.
Allow the water to boil until the straw is soft and tender. Strain the straw and allow it to cool to room temperature. Dump the straw into a plastic bag along with the oyster mushroom spawn. Shake the bag vigorously to evenly distribute the spawn.
Roll the top of the bag down to the top of the straw and secure with tape. Make several slits all over the surface of the bag. Place the bag in a cool, moist, dark place like a cellar or garage. Check the bag every few days and water it to keep the straw moist.
Harvest your mushrooms after two to four months. When harvesting, grasp the mushrooms by the base and twist gently so that the stems stay intact. This will allow you to harvest more mushrooms from the same batch later on.