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Gardening: Growing your own mushrooms

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oyster mushrooms

Oyster mushrooms growing on a roll of toilet paper. Tony Bertauski/Provided

This has been a strange semester.

I started teaching spring classes like I have for the past 22 years. And then, in mid-March, the education system went online. If you have kids, I’m sure you noticed.

The challenge has been to deliver engaging content. Since it was mid-semester, classes were in the middle of experiments that came home with me. Through the magic of an iPhone and a robust virtual classroom, I kept the experiments ongoing.

In the horticulture program at Trident Technical College, we discuss the vital role of microorganisms in a stable and thriving environment. Fungi are essential to nutrient availability, mitigating disease, and plant health. Many symbiotic fungi aid plants in nutrient and water uptake. In forest ecosystems, they help trees communicate as well as redistribute nutrients between trees.

Mushrooms are the fungal fruit much like the apple is on an apple tree. Edible mushrooms, those that won’t harm us when ingested, are nutritious and many are medicinal. Mushrooms only need the correct moisture, temperature and a food source to grow. In class, we cultivate mushrooms with a variety of techniques, all of which can be done at home. One of our methods involves toilet paper, a lab we started before the great toilet paper shortage in March.

Oyster mushrooms are one of the easiest edible mushrooms to grow. Many things serve as a food source for them, such as straw or grain. We used paper. The fact that it was toilet paper sounds a bit odd, but it’s a convenient way to execute on a small scale.

Each roll was dipped in water. If you’ve never done this, toilet paper soaks up water very quickly. Technically, the lab calls for boiling water and a pair of tongs to avoid contaminants. We experimented with cold water this year and had success.

After a quick dunk, a soggy roll of toilet paper was placed in a plastic bag with a filter patch to allow for air exchange. The cardboard roll was filled with inoculum. This is grain that has been colonized with the fungus that will ultimately produce oyster mushrooms.

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The bags were stored in the dark at room temperature. This would be the natural environment for fungal strands, or mycelia, to grow. With the right temperature, moisture and a readily available food source, the fungus spread through the cardboard tube into the paper. After four weeks, the roll began to resemble a small meringue cake.

Once fully colonized, the fungus senses its limited food source and will initiate fruiting. We moved the bags into indirect sunlight, an environmental cue for mushrooms to begin growing. We experimented with placing half the bags in the refrigerator for 48 hours. For some fungi, exposure to cold hastens fruiting.

Within a week, the frosted-looking paper rolls began to pin. These were clusters of small mushrooms. We found that the cold treatment did initiate fruiting faster than the bags kept at room temperature by a few days. There were a few other experiments to note. The rolls that were held in water for 10 seconds were contaminated by too much moisture. Bags that were left open were also contaminated.

Oyster mushrooms are ideally picked before the caps completely unfurl. Any debris can either be brushed off or cut away. Don’t wash them until they are ready to cook. They can be stored in the refrigerator for a couple of weeks. Ideally, place them in a paper bag to allow them to breathe.

In the years I’ve run this lab, I haven’t had one student interested in eating them. Maybe they don’t like mushrooms or that they grew on toilet paper. But I can confirm they are delicious. My wife is an excellent cook of toilet paper-grown oyster mushrooms.

You can purchase mushroom kits like this at Field and Forest ( or Mushroom Mountain ( Most are easy to grow and fun to watch. And remember that while some fungi cause disease, the bulk of them are beneficial to us and the environment.

Bon appetit.

Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback, e-mail him at

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