Grow-Your-Own Mushroom Kits Are Fun for Adults and Kids Alike

They grow super fast and are delicious to eat.

harvest day
Mushrooms on harvest day, only 11 days after starting.

K Martinko

Last month I received an unusual birthday present in the mail. My sister sent me what she described as a "moldy log" in her card, but was really a miracle waiting to unfold. It was a block of substrate inoculated with mushroom spawn, and when tended properly, would fruit into a magnificent crop of firm, chewy king oyster mushrooms.

My kids were utterly baffled by it. "This old thing will grow mushrooms?" they exclaimed in disbelief. I have to admit I shared their skepticism, but I followed the directions, which included cutting open the plastic bag, spraying the block inside with non-chlorinated water three times daily, and flapping the plastic bag to allow for airflow. 

mushroom substrate, day 1
Mushroom substrate on day 1, when I first opened the bag.

K Martinko

Our diligence was rewarded. Within a few days, little nubs appeared and before long they were doubling in size every day. They grew so fast, it almost seemed like they were growing before our eyes. When we harvested them, they were one of the most delicious things I've ever eaten—a consistency similar to scallops, fried in butter and olive oil with a bit of garlic and fresh basil added at the end. Even my mushroom-hating children downed them with some trepidation.

The whole idea of DIY mushroom-growing fascinates me, so I reached out to Emily Nigh, founder of Forest Floor, a new mushroom-growing company based in Winnipeg, Manitoba. When I described my kit to her, she expressed enthusiasm. 

"There are a ton of different kinds of oyster mushrooms you can grow—king oyster, Italian, pearl, blue, golden, pink, and others. While they all have the typical oyster shape, with gills running down the stem, they can be all different shapes and sizes," says Nigh. "My favorites grow in large clusters. The smaller the cap, the tastier they are for eating, and should be harvested while the cap is still curled under a tiny bit."

Oysters, she says, tend to be a popular choice because they're not picky about conditions and are so delicious. They should always be cooked, too.

My kit used a plastic bag to keep the substrate moist, but Nigh says she prefers plastic food-grade buckets. "Most growers grow in thin plastic sleeves with a filter, but [that creates] a lot of plastic waste," she says. "There are more and more urban growers, especially indoor growers, who are experimenting with alternatives."

mushroom growing bucket
Nigh's mushroom growing bucket.

Emily Nigh/Forest Floor

"What is the substrate made of?" I asked. I'd assumed it was a block of wood, but Nigh says it was probably straw or sawdust inoculated with spawn.

"Spawn is mycelium, cultured on sawdust and a little grain, under sterile conditions," says Nigh. "Most growers don’t produce their own spawn unless they have a lab, but there are many good sources for cultured spawn."

"Mycelium is the vegetative part of the fungus, which consists of a network of white filaments—you can see the bag is white before it fruits," she adds. "When you poke a hole in the bag, it releases CO2 and introduces oxygen, and fresh air inflow triggers fruiting out the hole, just like it would from a hole in a tree."

baby mushrooms
Tiny mushrooms starting to fruit, day 6.

K Martinko

That's why my kit said to keep it in a cool, dark place with the plastic bag sealed until I was ready to start growing. As soon as that air and moisture hit it, the mycelium sprang to life.

Nigh explains that, while my substrate-grown mushrooms tasted yummy, they're even better when grown on logs. (Although, she's doing some experiments growing on coffee grounds). This is her particular specialty, striving to replicate a forest setting in her own urban backyard.

"What I specialize in are oysters and shiitake, grown outdoors on cut logs by various methods. So-called 'forest-grown' mushrooms are superior in flavor and freshness, but they have a long spawn run—up to two years before they fruit," says Nigh. "The process involves drilling holes in logs (different wood types depending on the type of mushroom) and inoculating them with spawn. Then they are kept in the shade and put on a schedule of soaking, to keep them from drying out. I currently have a few hundred of these logs, kept in a rotation of stacks."

Once harvested, Nigh packages both fresh and dried mushrooms—she prefers sun-drying, as it dramatically boosts the vitamin D content—and loads them into her electric cargo bike for transport to the farmer's market. 

mushroom log
Shiitake mushrooms growing on backyard logs.

Emily Nigh/Forest Floor

Her company, Forest Floor, is based on an interest in small-scale urban farming, and on seeing how much food can be produced in a small space. "The aim is to keep my market base within a small, local sphere, that can be accessed and provided for by bicycle," she tells me.

I was sad to see that my DIY kit was a one-and-done deal. It might fruit again in two weeks' time if I keep spraying it regularly. But if not, I can plant it in the garden and possibly get another crop in the fall. Regardless, Nigh says "the kit is great compost once it has finished fruiting."

homegrown oyster mushrooms
Homegrown oyster mushrooms, 11 days after starting the kit.

K Martinko

If you've never tried a DIY mushroom-growing kit, I urge you to give it a try. It's a wonderful home science experiment for kids with much faster and more dramatic results than any other food-growing project I've tried.

As more people strive to reduce the amount of meat they consume, mushrooms are only going to become a more important part of our diets—and if we can produce them at home, or buy from local growers, all the better.