Plant–soil feedback (PSF) is an important mechanism to explain plant performance in natural and agricultural systems but is hard to quantify in field experiments. We used unmanned aerial vehicle (UAV)-based optical sensors to test whether PSF effects on plant traits can be quantified remotely. We show that PSF effects in the field occur and alter several important plant traits that can be sensed remotely and quantified in a non-destructive way at high resolution using UAV-based optical sensors.