Raising environmental awareness among farmers is the key to successfully reaching environmental goals. The present study assessed the knowledge development process and the raising of environmental awareness among 30 farmers from Poland exposed to four approaches aimed to reduce phosphorus (P) and nitrogen (N) losses to water. The farmers were interviewed with open-ended questions on-farm both before and after the project intervention. As hoped, the farmers attempted to adjust their farm practices to the European Union regulations, which are in some cases supported by subsidies. As a complement, the project offered tools for system-thinking based on farm data and support from agricultural advisors: a) a survey of plant-available P, potassium (K), magnesium (Mg), and soil pH, resulting in soil maps; b) assessment of nitrogen leaching risks from individual fields; c) compilation of a farm-gate balance. Farmers were positive to soil surveys and maps, but had limited understanding of the nutrient balance concept and calculations. They generally relied on their own experiences regarding fertilization rather than on calculated farm nutrient balances and leaching risks. Farmers’ understanding and willingness to adopt new approaches to improve nutrient efficiency and reduce negative environmental impacts are discussed.