The role of indigenous knowledge, derived from the experiences of millennia of predecessors and integrated over time, in the management of agricultural water resources is undeniable. South Khorasan gardeners, by understanding the limitations of water resources and relying on their indigenous knowledge, have sought to adapt the type and level of planting of their crops to this limitation. The purpose of this study was to investigate the role of indigenous irrigation knowledge in determining the pattern of planting of horticultural crops with emphasis on the role of Qanats in 15 villages of Alqurat district of central part of Birjand County. This research has been applied in terms of purpose and survey method.Data were collected through in-depth interviews, direct observation and document review. Using Cochran formula, 146 individuals were selected as sample size and then gardeners randomly filled out the researcher-made questionnaires. SPSS software was used for data analysis. The results showed that indigenous irrigation knowledge was effective in determining the pattern of planting crops and there was a relationship between the Qanat discharge and the pattern of planting crops including the type, arrangement and method of establishment and trees density. The findings of the study show that the gardeners of the study area have rich indigenous knowledge in terms of optimal water consumption management and can be used for policy making in agriculture and horticulture by combining it with technical knowledge.