Consider a container of adequate size with sufficient drain holes underneath and a tray to hold any amount of drained water.
Is it harmful for the plants in the container if the excess water in the tray remains high enough to contact the soil for long? If so, what does 'for long' mean? Is it universal or rather dependent on the species?
Each plant species adapts to its native local environment. A species on the rainy side of the mountain range will adapt to frequent and reliable rain, so it will make little effort to store moisture, not hesitate to open leaf pores to breathe, and will develop strong resistance to water borne bacteria and fungi in the root zone. On the dry side of the mountain where rain is much less reliable, a related species will adapt to grab and store as much water as it can when it can, keep leaf pores closed to retain what moisture it has, and will not bother to develop resistance to soil bacteria in the root zone, instead using the roots much more to breathe.
Moving a species to a different environment does not change its internal chemistry or inclinations. Moving the latter type to a strange environment and giving it lots of water continuously goes against its heritage. Forgetting to water the former results in a sad specimen. Raising the water table for both can have dire results.
So yes, it much depends on the species. In a commercial growing environment each plant gets individual attention. In other environments we frequently see stressed plants.
We plant all our above-ground plants in containers with reservoirs.
We haven't had any plants die on use for over-watering. This includes chillies, tomatoes, strawberries, eggplants, okra, capsicums, blackberries, raspberries, lettuce, and houseplants
Self-watering cone
Self-watering planter example
Self-watering Vegepod
Note, links are posted because I got the images from them. I am not associated with any of these, they are just first ones in the search.
