Grow Your Own Gourmet Mushrooms (cont)
By: Charlie Nardozzi
More Mushrooms by the Log
Even though kits are the simplest way to produce gourmet mushrooms, the small harvest they produce may only whet your appetite. A more economical method is to buy spawn and inoculate hardwood logs yourself. Many gourmet mushrooms (including all mentioned above except button, crimini, and portabello) can be grown this way.
Compared to sawdust- or straw-based kits, logs provide more food for mushroom growth, producing a higher yield of mushrooms over a longer period more economically. For example, a ready-to-fruit kit costs about $20 to $30 and produces 1 to 2 pounds of mushrooms in one to two months. That's about $15 per pound. A $20 log-based kit inoculates about five logs. Although you'll need to wait 9 to 12 months for the first fruits to form, fruiting will continue periodically over four years, eventually producing about 20 pounds of mushrooms total. That's about $1 per pound. If you can't wait, some mail-order companies provide preinoculated logs with the mycelia already running throughout the log. Though more expensive than producing your own (about $38 per log with kit and soaking tray), these will usually produce mushrooms within a week of arrival, yielding 4 pounds over three to four years.
Growing your own mushrooms from logs takes more time, materials, and care than using the ready-to-fruit kits. Shiitakes, which are among the most popular log-growing mushrooms, require that you cut logs of the right type and age, inoculate them with plugs of spawn, and keep them at the correct humidity and temperature for fruiting. Follow these steps for growing mushrooms on a log.
Indoor Shiitake Step-by-Step
1. Use nonaromatic hardwoods such as alder, oak, sugar maple, or sweet gum. Cut 3- to 6-inch-diameter logs into 3- to 4-foot lengths one to three months before inoculating in spring. Spring-inoculated logs will probably fruit in fall in southern areas and in the following summer in northern area. Drill 5/16-inch-diameter, 1-1/2-inch-deep holes 4 to 6 inches apart within the row and 1-1/2 inches between rows all around the log.
2. Inoculate your logs with a plug kit -- spawn formed into small plugs you pound into holes. A kit with 300 plugs costs about $20, enough for six logs. Gently tap a plug into each hole with a hammer or mallet.
3. Seal the plugs with melted beeswax or cheese wax to retain moisture. Stack the inoculated logs perpendicular to each other in a shady, moist, sheltered location. Under an evergreen tree on the north side of the house is ideal. Water periodically to keep the logs moist, but allow them to dry out between waterings. After 9 to 12 months, you should notice irregular circles of white growth on the cut ends of the logs. This means fruiting is imminent. You can let nature take its course and allow the mushrooms to fruit when weather conditions are favorable, or you can force them by soaking the logs overnight in barrels of cold water. This shock will start the fruiting process. After fruiting finishes, let the logs rest for six to eight weeks before repeating the cold water immersion.
Charlie Nardozzi is a senior horticulturist at National Gardening.
Photography by Bill Lorenz