Methane gas resulting from combining cotton gin trash and dairy manure in a two phase anaerobic digester is easily marketed. Digestate solids are not. This study was conducted to determine digestate toxicity and its potential as a soil amendment. Compost was prepared in two ways (anaerobically and conventionally) from the same mixture of dairy manure and cotton gin waste. Lettuce was grown in pots filled with different proportions of anaerobic or aerobic compost mixed with sand or native soil. Fresh and dry leaf mass were used as indicators of plant growth. Germination and emergence were not statistically different, indicating that even full strength digestate is not toxic. Potting soils with various amounts of conventional compost had an order of magnitude greater nitrate (NO3-N) and produced yields that were an order of magnitude greater despite having more sodium. Anaerobic digestate used as potting soil did not compare favorably with conventional compost made from the same materials. However, its lower sodium content makes it more attractive in the long run.