I only have a small tray below my pot and I have another situation where I'm using a bucket and a bowl as a container for run-off water. For the main suffering plants there's some room for wicks (maybe a couple of centimeters total) since the pot is slightly hollow from underneath. The reason why my plants are MG deficient is because my soil PH is below MG availability range, hence the roots can't absorb it from the soil. I think it would be pain in the ass to maintain or set up (for the bucket at least, since it has a lot of soil between the roots and the plant, where as my other pot has very little soil under the roots). Holes below the pot are not equally distributed, how would I stick the wick in and guarantee that mg will reach the plant? I like the wick system, but for me it would create a bunch of other problems (no room for new run-off water from watering [existing tray is too small to contain enough water], no space for a new resevoir etc). I have to mix and match everything here and right now all my plants are sitting on the same level and lights are adjusted equally. I think I would be better off watering with a mildly salted water to see how it goes first and hopefully the plants will be able to absorb some of that MG that gets in contact with the roots.
Thanks.