With some caution: This works for specific plants only. I'm getting into cacti and other succulents as a hobby and I'm learning that minimal water and minimal s

With some caution: This works for specific plants only. I'm getting into cacti and other succulents as a hobby and I'm learning that minimal water and minimal soil fertility is actually the desired environment... which means such a monitor wouldn't help me. (This possibly also applies to bonsai- there is several overlapping growing mediums which makes me suspect this is the case.)