Concentrated Humus Reduces Disease Note: John & Bob's Soil Optimizer consists of the concentrated humus used for this study along with three other organic ingredients to maximize benefits by blending calcium, iron, and soluble concentrated humus. Concentrated humus treatments also reduced dollar spot incidence at Virginia Tech. Dollar spot incidence was evaluated on July 11, 1997, on a scale of 1 to 9, where 9 indicated highest dollar spot incidence. Concentrated humus creates a more favorable environment for plant growth and strengthen the plant's natural defenses. It also promotes the growth of beneficial fungi and bacterial species in the soil to discourage plant pathogen populations through competition.