Previous studies have shown that use of an anaerobic digester for treatment of manure and whey mixtures has not been profitable for farmstead cheese operations in the United States because of the large capital expenses and low energy prices. Our objective was to determine the feasibility of using the biomass produced by anaerobic digestion as a substitute for peat moss (a non-renewable resource) that is used extensively in gardening and potting mixes. Cow manure and a manure-whey mixture containing 15% cheese whey were anaerobically digested in a 60 L induced bed reactor to steady state with a hydraulic retention time (HRT) of 10 d at 35°C. The effluent was collected and sent for microbial profiling as a soil amendment. Mean reduction in total fungi and protozoa (flagellates, amoebae and ciliates) from their initial levels of 3 × 10³ mg/mL, 7 × 10⁴/g, 3 × 10⁶/g and 4 × 10²/g was 99.9, 99.2, 99.8, and 96.8%, respectively. Reduction in COD was 87.5% and and 92.1% for manure and manure-whey mixture, respectively. The effluent was then air-dried and analyzed for its water holding capacity and suitability for use as a potting mix by measuring total porosity, and air capacity in comparison to a commercial potting mix. Both digested manure and manure-whey effluents were significantly (P < 0.05) higher in all 3 categories. The digester biomass had almost double the total porosity (66.7%) and water holding capacity (61.0%) of the potting mix (38.1%, 35.9%). Based on computer modeling of anaerobic digestion it was determined that maximum biomass production could be achieved if the HRT was reduced to 3.3 d. For a 210-cow in which manure is mixed with 25% whey this would produce 3.93 yard³/d of biomass and 12,300 ft³/d of methane. Based upon this scenario, net present value (NPV) and internal rate of return (IRR) at 12% discount rate over 20 years was dependent on the wholesale price of the biomass and the renewable energy credits (REC) for electricity generated. At a REC of $0.01/kWh and $0.95/ft³ for biomass, the NPV is −$18,205 and IRR is 7.64%. This increases to NPV of $114,926 and IRR of 34.7% if the biomass is sold at $1.45/ft³ in comparison for peat moss that is sold at $2.45/ft³.