Adding carbon-rich solids from pyrolysis (pyrochars) and hydrothermal carbonization (hydrochars) to soils can improve their hydraulic properties and increase the plant available soil water capacity (AWC). However, the effects of the specific char characteristics on soil hydraulic properties are still little understood and thus, difficult to optimize for soil amendment. It is often assumed that the water repellency of chars is an important factor influencing the water retention of soils. In using the evaporation method and saturated conductivity measurements, we investigated how changes of hydraulic properties of a loamy sand with 2% (w/w) char addition depend on (i) production processes, (ii) feedstocks, (iii) particle size, and (iv) wetting properties of added chars. Applied chars comprised pyrochars carbonized at 750 °C and hydrochars carbonized at 200 °C and 250 °C from two different feedstocks (digestate and woodchips) and two particle sizes (< 0.5 mm and 0.5-1.0 mm). The wetting properties of the pure chars and soil-char composites were determined by the sessile drop method. To investigate the impact of the water repellency of chars, pure chars and soil-char composites were saturated by capillary water uptake under atmospheric conditions and by saturation from the bottom under vacuum conditions.