Soil Moisture

One of the ideas that greenscaper is advancing is use of bottle planters to become familiar with the relationship between plant, light and moisture. He can articulate the concept and how-to better than I can, but through a combination of measured watering, observation/measuring of light levels, observing the plant growth and simply peering through the clear container at the roots and soil, one can gain a better understanding of plant needs (rather than blindly subscribing to self-watering container dogma).

While the measured watering method is easily achievable with bottle planters, how should this be applied to commercially available sub-irrigated planters, where their heft makes it impractical? Use of a soil probe and common sense. I'll post more on this in the future.