slightly
稍 centers on a small degree or margin: something is only slightly, a little, or gradually so. The meaning is about being just a bit, not fully or completely.
稍 combines 禾 (grain) with 肖, which likely contributes the sound. The original sense may relate to the tip of a grain stalk, suggesting something small or slight.
Grain 禾 and the shape 肖 suggest a tiny tip of a rice plant. Just the very tip—only slightly, not the whole plant.
For ソウ, imagine a grain stalk so slightly bent that it looks like it's bowing: 'sow' (as in bowing) -> ソウ, just a slight bow.