By Bev Johnson

Master Gardener

Gardeners get itchy this time of year. Some of them have started collecting more houseplants, even though their housemates are complaining they can’t see out the windows because of all the plants on the windowsills. Others are knee deep in seed catalogs, graphs, a list of what did well last year, what seeds they have, how old, etc. They get upset when they have to clear the kitchen table so the family can eat. 

If you recognize yourself in one of these pictures, there is another way to go to scratch that gardening itch; it’s growing mushrooms. The people at the University of Minnesota Extension service insist it’s pretty easy, and not really weird at all. Of course, first you have to like eating mushrooms.

The biggest mental block preventing people from growing mushrooms is that they grow from spores, not seeds and you can’t just buy a packet of spores and dump them in the ground and get mushrooms. Spores must be collected in a relatively sterile environment, then used to inoculate grains, seeds, or dowels to produce spawn. This is the “vegetatively growing fungal tissue scientists call mycelia.” Spawn is the “seed” to the mushroom grower.

Now that you have the spawn, you have to have something for it to grow on. Different mushrooms require different growing conditions or different “substrate” or growing medium. Since mushrooms have no chlorophyll, they must get all their nutrients from whatever organic medium they are growing in. This can be corncobs, cotton seed, sawdust, straw, logs, gypsum and nitrogen supplements. The medium is sterilized then the spawn is either worked into the compost or the spawn covered dowel is inoculated into the log.

Getting the mycelia to fruit requires as little as watering, (or for the white button mushroom) submerging the log or block in cold water for 24 to 48 hours. This can be a real log, or a bag inoculated with shitake or other types that need this treatment. Fruiting can take from 2 weeks to 2 months. You can’t go by size to determine ripeness as they vary from very small buttons to large caps. Crops can be harvested over a period of several weeks to as long as several months.

Now that you have decided to try growing your own mushrooms, the next question is how to get started. You can buy a kit that has everything you need, or buy starter culture (spawn), and getting the medium separately. For the first timer, the kit is the way to go.

The easiest to grow are the common grocery store mushrooms. Kits have spawn usually covered by sphagnum moss to keep the compost moist. You just need to get the compost wet then mist it daily. After the mycelium has covered most of the compost, you briefly chill the box. Mushrooms will pop up in about 1 to 3 weeks.

For the more gastronomically daring, try oyster mushrooms. This kit will have a bag containing a mycelial covered block in a bag.  You water the bag well then stick dowels or sticks under the bag to tent it, so it doesn’t touch the block. The fungi are alive and need to “breathe”. A fluorescent light, or daylight, not direct sunlight will encourage fruiting. Small bumps will start pushing through in 1 to 2 weeks. As the mushrooms start to form continue to mist lightly. Too wet will make them rot. After the first crop, continue to mist as the mycelium will digest more compost getting ready for the next “flush” of mushrooms.

An excellent Christmas gift for gardeners with itchy fingers and, in some cases, lots of patience.