Because of limited space for gardening, we have a fairly large number of trees and plants in flower pots. In particular I have found that citrus trees seem to demand a lot of mulch around them and so I am doing sheet mulch and in place composting in the pots. There is usually a 2-4 inch layer of leaf fall mulch covering a thin layer of kitchen waste in these pots. The leaf fall is currently mostly mango and papaya leaves. The mango leaves are usually green when put in, the papaya leaves may be harvested when the show that they are about to fade. I would assume most of this would be considered a "green" for composting purposes and that the soil and plant acts as the main nitrogen sink. Sometimes I add mango twigs as a brown, however.
I would also like to add that most pots contain between one and three different plant species. Examples include lemon and ginseng, eggplant and ginseng, some sort of sour starfruit relative, celery, and ginseng, eggplant, lime, and durian, and the so forth (yes I am growing a lot of ginseng-- I have almost 20 ginseng plants and counting, most of which are only a few months old).
My question is this. When composting above-ground parts of plants in an area where there is not much topsoil, such as a flower pot, to what extent do I need to worry about allelopathy between plant species? Is this a serious issue I need to keep a close eye on? Or is it less of an issue since typically I am not dealing with a lot of roots?