Greenhouse Gas Budget Assessment of Production of Kentucky Bluegrass (Poa pratensis) Sod and Three Herbaceous Landscape Plants

To mitigate climate change, achieving net-zero carbon dioxide (CO2) emissions across all sectors is essential. In the floricultural and landscaping industries, a key concern is whether the production and use of landscape plants contribute to CO2 reduction. However, few studies have assessed the greenhouse gas (GHG) budgets of landscape plant production. This study quantified all major components of GHG budgets to determine whether herbaceous plant production acts as a GHG sink or source. Kentucky bluegrass sod and three herbaceous plants (Hedera canariensis, Liriope muscari, and Tagetes patula) were investigated for their GHG (CO2, CH4, and N2O) budgets. For Kentucky bluegrass sod production, the total GHG budget was calculated as −17.764 t-CO2e ha−1 year−1, comprising carbon sequestration (23.014 t-CO2/ha), GHG fluxes (0.049 t-CO2e/ha), and GHG emissions from energy and resource consumption (5.201 t-CO2e/ha). These results indicate that Kentucky bluegrass sod production functions as a GHG sink. In contrast, the total GHG budgets for potting production of the three herbaceous plants were positive, primarily due to higher GHG emissions from the use of potting soil and granular pesticides. To reduce net CO2 emissions in herbaceous plant production, using biochar as a growth medium and minimizing granular pesticides is an effective approach.