Project Overview
Commodities
- Vegetables: greens (leafy), peppers
- Additional Plants: herbs
- Miscellaneous: mushrooms
Practices
- Soil Management: composting, amendments
Abstract:
Thousands of tons of spent coffee grounds (SCG) are sent to landfills each year, and with the recent growth in cold-brew coffee production this is expected to increase. Waste utilization is a key component to sustainable agriculture and creating a circular economy. The use of SCG in agriculture can improve soil properties and plant growth by increasing organic matter and nutrients. Increasing sustainable practices in the horticulture industry has been an ongoing dilemma for many years. Sphagnum peat moss is the main ingredient of commercial potting mixes and when harvested releases large amounts of CO2 into the atmosphere. A number of organic wastes such as composted bark have been tested, and somewhat adopted by some growers as a substitute for peat-based potting media. There are a number of possible uses for SCG due to their valuable physical, chemical, and biological qualities. Our research investigated the use of non-composted and composted SCG (CSCG) as a source of ammonium and nitrate when added to soil. We also studied the effect of SCG on germination, growth and carotenoid concentration when amended to a potting mix.
Our research demonstrates:
1. Composted SCG can act as a biostimulant for seed germination (spinach, radish, pea, eggplant, basil) when used as a partial peat replacement. Future research should include a variety of different plant species and an investigation of the mechanisms responsible for the biostimulant effect on germination.
2. Composted SCG can be used as a partial replacement for peat-based media with no effect on biomass, but should be used at species-specific rates.
3. SCG may serve as a long-term fertilizer due to the time it takes to mineralize. They may increase the nutrient and water-holding capacity of soil, which can improve plant growth over a shorter time period.
4. Carotenoid concentrations showed no clear trends and further research is needed for conclusive results.
Project objectives:
- Develop research-based data to establish composted spent coffee grounds as a viable peat substitute by assessing the range in physiochemical properties of different proportions of composted SCG (CSCG) and peat-based media mixtures and leachate from the mixture creating more sustainable and cost-effective practices.
- Improve the competitiveness of basil and eggplant by enhancing their nutritional properties without increasing economic inputs by evaluating the effect of composted and non-composted SCG on their growth and carotenoid concentration.
- Characterize the nitrogen mineralization dynamics of composted and non-composted SCG compared to other commonly used fertilizers