Due to increasing world population and increasing water demand pressure on limited fresh water resources, studies have focused on more effective water uses. One of the effective water using ways is rainwater harvesting. In this study it was intended to increase soil moisture for crop production in semiarid areas in Karapınar Desertification and Erosion Research Center. Ridge and furrow system called micro catchment water harvesting methods were applied in the study. The effects of different ridge widths and different covering materials on soil moisture were investigated. The treatments consisted of three ridge widths (g1= 30 cm, g2= 45 cm and g3= 60 cm) and two different covering materials (P= plastic mulch and S= straw mulch) and compressed soil ridge (T) as rain water harvesting application and a conventional soil cultivation and growing melon on flat area as a control. A fixed 50 cm-width furrows were left to allow harvested rain water infiltration and also to grow melon in water harvesting treatments. The experiment was conducted in a randomized complete block design with split block with three replications. In all plots soil moiture was monitored with a neutron meter up to 90 cm depth. During the growing period the highest precipitation was 46.6 mm in Jun 2015. According to soil moisture measurements after the rainy period, the highest soil moisture content was 294.6 mm in 0-90 cm deep at plastic covered ridge which had 60 cm ridge width at 30 Jun 2015. After that, decreasing order of soil moisture were Pg2 (277.8 mm), Pg1 (261.9 mm), Sg3 (209.3 mm), Sg1 (205.9 mm), Sg2 (204 mm), Tg1 (200.3 mm), Tg2 (194.9 mm) and Tg3 (194.8 mm). The control plot had the least soil moisture with 170.2 mm. The highest soil moisture was determined in Pg3 during the trial period. It was observed that even a small amount of precipitation caused increases in soil moisture for water harvesting treatments especially in the plastic covered ridge plots. Although the increased accumulation of moisture in the soil with increased ridge width it wasn`t obtained marketable melon yield in Karapınar region due to lack of enough precipitation.