What is SMS?

Spent Mushroom Substrate (SMS) is a composted, growing medium that results from the mushroom growing process. SMS is generically refered to as muchroom compost. SMS is made from agricultural materials, such as wheat-straw, bedded hay, poultry manure, cottonseed meal, cocoa shells and gypsum. Mushroom production takes place in specialized, climate-controlled rooms and lasts for approximately 70 days before new compost is required.

When new compost is needed, the SMS remaining from the completed mushroom crop is steam pasteurized to reduce hygienic problems for the next mushroom crop, and is then removed from the growing rooms. SMS can be used for other agricultural crops and products since it is an ideal soil amendment with important nutrients and other attributes.

To download an SMS brochure, click here. To download an SMS booklet that contains more detailed information about what SMS is and how it can be used, including scientific research and practical applications, click here.

Why Use SMS?

The most valuable aspect of SMS is its high organic matter. This allows soil to retain moisture in dry weather and shed it during wet weather. By creating air spaces, SMS acts a sponge in gravel or sandy soils and permits clay soils to drain. SMS will not leach from the ground. Nutrients remain in the soil and, unlike inorganic fertilizers, do not contribute to groundwater pollution if applied correctly. There are many advantages of SMS over other composts produced from food and garden wastes including:

• A consistent, formulated and homogeneous product. The SMS production cycle occurs all year-round with consistent materials and compost products.
• High water and nutrient holding capacity, SMS includes sphagnum peat and an organic matter formulations resulting in moisture and nutrient retention.
• The pasteurization process of SMS ensures that weed seeds cannot enter the product.
• No nitrogen “draw-down” problems. Unlike wood and paper wastes frequently found in other products, SMS has been supplemented with nitrogen.
• Absence of heavy metals, reduces consumer concerns and associated heatlh risks.