In order to assess the possibility of using waste from agri-food processing for fertilization, residues in the form of apple pomace, carrot root, onion husks and dried nettle were selected for the tests. The research material came from food plants located in north-eastern Poland. In selected waste, the pH value, dry matter content, organic matter, nitrogen, phosphorus, potassium and carbon were determined. It was found that apple pomace, carrot root and onion husk were acidic and dried nettle was alkaline. The nitrogen content in the tested waste ranged from 0.61 to 2.29%, phosphorus from 0.07 to 0.55%, and potassium from 0.19 to 3.72%. Based on the results obtained, it was found that the examined post-production residues are characterized by good fertilizer properties. However, it should be remembered that fertilizers or soil improvers must meet a number of requirements and above all, they must be safe for the environment.