ASHS 2024 Conference

The integration of sustainable technologies in waste management systems has become imperative in addressing the escalating challenges of agricultural productivity and sustainability. Plugs are essential when starting crop production in controlled environment agriculture (CEA) setups and greenhouses. Horticultural crops such as vegetables, fruiting, and ornamental plants that utilize plugs have demonstrated higher success rates, healthier plants, and higher total yields. The APS Laboratory for Sustainable Agriculture at explored the innovative utilization of digestate from the Home Water-Energy-Food Systems (H-WEF), the H-WEF system converts household food waste into biogas, electricity, and nutrient-rich digestate. The digestate from the H-WEF system was used to produce agricultural plugs, presenting a novel approach to circular resource utilization. We carried out the growth of Rex Butterhead Lettuce Latuca Sativa plugs with eight different treatments, 1) control synthetic fertilizer; 2) 5% Digestate – 95% RO Water (5D–95RO); 3) 10% Digestate – 90% RO Water (10D–90RO); 4) 15% Digestate – 85% RO Water (15D–85RO); 5) 20% Digestate – 80% RO Water (20D–80RO); 6) 25% Digestate – 75% RO Water (25D–75RO); 7) 30% Digestate – 70% RO Water (30D–70RO); 8) 35% Digestate – 65% RO Water (35D–65RO). The seeds were sowed with their fertigation treatment and watered every day. The plugs were cultivated for 15 days in a controlled environment until two leaves had developed after the cotyledon. After 15 days, we collected data on wet weight (g), plug head area (cm2), total leaf area (cm2), total nitrogen content (mg/g), total chlorophyll content (mg/cm2), and dry weight (g). In addition, we collected data on the Leaf Area Index (LAI, cm2/cm2) and Specific Leaf Area (SLA, cm2/g). The synthetic fertigation yielded a higher wet weight than the following treatments: 5D–95RO, 10D–90RO, and 35D–65RO. While the 30D–70RO treatment produced a larger plug head than all other treatments. The digestate-based fertilizers were comparable to the synthetic fertilizer at dilutions of 25D–75RO and 30D–70RO. Results from this study may inform growers about the viability of utilizing digestate for plug production.