Rahmat Syarif, Violita Violita, Irma Leilani Eka Putri and Dezi Handayani 2022. The Effect of Use Ground Coffee (Coffea arabica L.) as a addition Nutrition To The Growth of Spinach Plants (Amaranthus hybridus L.) In Hydroponics Systems. Prosiding Seminar Nasional Biologi. 1, 2 (May 2022), 1440–1449. DOI:https://doi.org/10.24036/prosemnasbio/vol1/262.