I was curious if there are any existing resources or documentation on optimal soil moisture by plant type? E.g. A Peace Lily grows better in moist soil vs. a Cactus. I’m essentially looking for any documentation that outlines differences in soil moisture needs by plant type; either qualitative (soil wet/dry to the touch), water content in soil (volumetric water content or gravimetric water content), or matric potential in soil (kPa). I’m doing some research on optimal watering techniques by plant type and have been unable to find existing info on this. Thanks!
Thank you for contacting Toronto Master Gardeners.
Here is an excellent overview article on optimum watering techniques for plants: Watering Plants Correctly – When and How to Water . Essentially, you water when the soil needs more water.
Documentation with quantitative data tends to focus on soil moisture requirements for specific crops, for example, this Food and Agricultural Organization report on water harvesting, or this paper from Iowa State University on soil moisture conditions and crop water use.
In terms of resources or documentation on optimal soil moisture by plant type, moisture meter manufacturers appear to offer the most comprehensive lists. For example:
This guide lists recommended soil moisture levels (four categories from tolerates extremely dry soil to tolerates wet soil) by plant type.
This table lists qualitative soil moisture requirements for various house plants.
Good luck with your research.