The USDA Forest Service requires approximately 550 cubic yards of an 80/20 peat moss–vermiculite container planting mix meeting the specified physical, chemical, and packaging requirements. Material shall be delivered in opaque tote bags to the USDA Forest Service Placerville Nursery, 2375 Fruitridge Road, Camino, CA 95709 in the Eldorado National Forest.
• The mix shall be 80% peat moss and 20% Vermiculite or agreed upon ratio.
• Peat Moss specs: Choice cut sphagnum peat moss, vacuum mined, light (blond) peat color, percentage of fines in peat to be less than 8% from the #100 mesh sieve with a course/fine ratio of 1:2 using the # 10 sieve.
• Vermiculite specs: #2 grade agricultural (horticultural) vermiculite, no more than 10% of fines, less than 1mm in size, and certified to be asbestos free.
• Mixed media will have a bulk density of 0.09 gm/ml, pH range after wetting 4.0 – 5.4, dry density will be 8 to 10 pounds per cubic foot, salinity (salt) shall be less than 1.5 mmhos/cm, and media shall contain a wetting agent like Aquaduct at a rate of 1 pound per cubic yard.
• Media shall have a moisture content of from 25 to 40 percent by dry weight and aeration porosity shall be between 25-35%.
• Desired exchangeable nutrient range includes nitrogen, phosphorous, potassium, calcium, magnesium, iron, copper, zinc, and chlorides within specified parts per million.