In 2002-2003, studies were carried out to investigate the effect of the duration of weed covered period on leek production by designing the experiments as randomised blocks. Following the emergence of plants to soil surface weeds were taken off at 10 days intervals during a period of 50 days (permanently weed free, 10-, 20-, 30-, 40-, 50- days weed covered and permanently weed covered). In the completion of the study, the highest yield was 28407kg ha(-1) from weed free fields. This was followed by fields where weeds were taken off after 10 days (27312kg ha(-1)), and 20 days (26793kg ha(-1)). The lowest yield of 3079kg ha(-1) was obtained from continuously weed covered fields.