Nitrogen and spent coffee ground for enhancing nutritional, morphological, flowering and antioxidant properties of Chrysanthemum (Chrysanthemum morfolium Ramat)

Chrysanthemum is one of the most attractive flowering plants widely grown commercially worldwide. Having a good source of organic fertilizers plays an important role in meeting the increasing demand for these plants, which requires high-quality flowers and a high survival time for the longest period. The effect of nitrogen (N) coupled with spent coffee ground (SCG) at various levels (0.0, 2.5, 5.0, 7.5, 10.0°% w/w) was evaluated on growth performance and chemical components of the Chrysanthemum over two years in a pot scale. Overall, total dry matter (TDM) was significantly enhanced with N+ by 125 and 97°% over N− in the first and second years, respectively. SCG also enhanced TDM up to the highest level of application in the range of 27–98°% and 18–81°% over SCG (0.0°%) in the same years, respectively. The interaction effect between N and SCG was perfect on TDM, flower number, and flower dry weight. Similarly, total antioxidant activities when N and SCG were coupled together gave respective increments ranging from 11.8 to 45.9 U/g DW and from 2.1 to 15.9 U/g DW compared to N alone (5.8 and 0.9 U/g DW) in both leaves and flowers, respectively. Extracts of plant treated with N and 10°% SCG exhibited a higher content of rosmarinic, caffeic, chlorogenic, vanillic acids, and rutin in the leaves. SCG as a natural organic source is easy to obtain and is a practical and cost-effective solution to plant nutrition, which can be valuable for ornamental plants, especially when combined with nitrogen. [Display omitted] •Fresh SCG either alone or with N was applied to growth media of Chrysanthemum plant.•Nitrogen and SCG enhanced TDM in the range of 36–69°% over control.•Flower number was the main reason for the increase in TDM more than flower dry weight.•SCG at 10°% with N nearly doubled antioxidant activity in the leaves and flowers.•Soil pH and plant species should be considered before using SCG as a biofertilizer.