"One inch of water"

[IDemo]

2. So it's still a subjective measure

What it comes down to is the variables of local climate, soil conditions and container versus earth planting. Wouldn't it be more helpful to simply advise the optimal soil moisture for a given plant? Say, "keep uniformly damp without allowing soil to dry out, but not drenched". Most people (well me, anyway) are going to have a much better idea of how much water is needed to meet this description than by having to guess what is meant by 'inch of water' or by having to calculate that volume.