Crop rotation with specific crops and green manures can help prevent the spread of perennial weeds and improve crop yields and quality in organic farming. To suppress weeds effectively, it is important to follow certain rules like incorporating green manures in rotations, avoiding growing low-competitiveness cereals for too long, and choosing crops with high weed competitiveness in fields with heavy weed pressure. For instance, avoid planting grain legumes where perennial weeds are an issue, and do not sow winter crops after lupine or broad beans. Instead, undersow cover crops and choose competitive crops wisely. Proper management of poorly established crops and cover crops is crucial to prevent weed dominance. On sandy soils, consider planting rye, triticale, or winter spelt instead of winter wheat to discourage perennial weed growth.