Woodland Valley Mushrooms, Jackson SC

... mushroom production
from spawn to food ...

The Elements

Mushroom production, be it for personal use or on a commercial scale, requires some basic elements.

Spawn is usually sawdust with mushroom mycelium mixed in. Mushroom mycelium is mushroom spore that has started to root. Although it is possible to start with spore, it is tricky and best left to the professionals, so buying spawn from a home gardening supply store or using spawn in a mushroom growing kit is a better option for beginners. A version called plug spawn is specifically designed for use with newly fallen hardwood. All spawn should be used within a short period of time or refrigerated until use.

Substrate is organic matter that serves as food for the spawn. In nature, mushrooms grow naturally in soil, manure, decaying leaves, and downed hardwood. Substrate can be made from any organic materials containing carbohydrate and nitrogen. Typical substrate materials include cardboard, coffee grounds, wood chips, straw, and compost. Each type of mushroom grows best in a substrate designed for it.

temperature control
Mushrooms require warm temperatures during the colonization phase, and cooler temperatures once fruiting begins. Commercial operations have rooms with temperature control, but a warm room or heating pad can be used for home mushroom farming.

humidity control
Some moisture must be present throughout the mushroom production process. Commercial operations have rooms with humidity control, but misting with a spray bottle can be sufficient for growing mushrooms on a small scale.

light control
Direct sunlight inhibits mycelium growth in the colonization phase. Most mushrooms require only blue light for proper fruiting body development.

Some ventilation is required to help dispel the carbon dioxide given off by the growing mycelium. In a home environment, a fan can be used to keep air moving as long as there is no direct draft.

The Process

Create Mushroom Compost

Mushroom compost, the substrate or growing medium in which mushrooms develop, is created when the raw organic ingredients are converted by the activity of microorganisms, heat, and heat-releasing chemical reactions. The composting process takes a week or two and requires the optimal combination of moisture, oxygen, nitrogen, and carbohydrates. For best yield, the compost is customized to the specific preferences of each type of mushroom.

Pasteurize or Sterilize the Substrate

In order to prevent contamination from unwanted spores or molds, the substrate must be pasteurized or sterilized using heat an/or boiling water. It is essential that all surfaces cleaned with antibacterial agents during this phase to ensure that they are free from contaminants.

Inoculate the Substrate with Mycelium

First it is essential to sterilize all areas and tools with antibacterial soap or alcohol to avoid contamination.

Spawn (containing sterilized grain and germinated mushroom spore) is mixed or inserted into the substrate. Although mushroom growers can create their own spawn, the process is specialized and complicated, and most mushroom growers purchase spawn from commercial sources.


During this period, the spawn colonizes the substrate with mycelium. White patches of mycelium gradually appear, develop, and grow. Mycelium is always white, so any other color indicates that the substrate is contaminated and must be discarded. Full colonization takes 2-5 weeks, depending on the kind of mushroom.

The temperature should be steady and maintained between 60° and 75° F. A small amount of moisture is necessary, but standing water and saturated substrate must be avoided. The room can be dark or dimly lit; bright light inhibits colonization.


Once the mycelium has formed a thick mat, it is ready to fruit and produce mushrooms. The temperature requirement at this stage is lighter, 55° and 80° F, and humidity over 90% is necessary.

When the mushrooms first appear, they are called buttons. Over the next few days, the button grows larger and develops a stem. The bottom of the button separates from the stem, and becomes a mushroom cap. The cap gradually opens, becoming a cup and finally a flat. When the cap starts to invert and the edges become wavy, the gills under the cap are mature and ready to dispel spore.

Each flush of mushrooms lasts 3-5 days, after which mushroom growth is dormant for a few days. Harvesting can continue for several weeks or even months if the conditions are ideal. Once all mushroom growth has stopped, the growing medium cannot be re-used because all of its nutrients have become food for the mushrooms. It must be composted, and the cycle begins once more.


Mushrooms can be picked at the cap, cup, or flat stage. Harvesting mushrooms is labor intensive, as each must be stabilized around the stalk with one hand while the stalk is gently twisted off of the base. This is done to prevent the mycelium that is still developing mushrooms from being disturbed. Once harvested, mushrooms are used immediately, refrigerated, packaged for distribution, or dried for future use. The mushrooms can also be pickled for longer shelf life.