“…Rooting depth is also exceedingly difficult to measure in soil. Rooting depth can be easily measured in (typically small) plants grown in artificial media, with the most extreme example being humid air (“aeroponics” [Awika et al., 2021; Eldridge et al., 2020]), but also commonly including agar plates (Guseman et al., 2016; Ogura et al., 2019), solution culture (Mathieu et al., 2015), paper growth pouches (Atkinson et al., 2015), or systems in which roots grow in solid media against a transparent surface (Deja‐Muylle et al., 2021; LaRue et al., 2022; Nagel et al., 2012; Rellán‐Álvarez et al., 2015; Yuan et al., 2016). Such systems are useful in specific contexts but may not be correlated with root phenotypes observed in natural soil, which has many characteristics capable of influencing root growth including, but not limited to, mechanical impedance, soil biota, and hypoxia (Poorter et al., 2016; Rich et al., 2020).…”