Sorry, but fluoride is among reasons for leaf burn. As stated in the article by George (Doc) and Kay Abraham which was linked to (just above), "Easter lilies, dracaenas, spider plants and marantas actually have been proven susceptible to leaf scorch injury from too much fluoride in their soil." Among the several sources of fluoride which affect those senstitve plants is perlite (AKA sponge rock), fluoridated water, and some fertilizers. So, dormilona, what plants are affected? Beyond that, probably most common reason for leaf burn in potted plants is insufficient water to the top of the plant. That can occur from multiple reasons, among them these: -- dry potting mix; and/or -- excess water at the roots; and/or -- erratic watering; and/or -- recently transplanted; and/or -- excessively low humididty.

I've been growing radishes pretty much everywhere. Generally they seem to be ready for harvest before the main plants are big enough for their to be any competition.

Maybe a little old fashioned, but Tidal Wave Petunias work great in hanging baskets and they LOVE hot sun. Tidal Waves are mostly self cleaning, which is a big plus for me.

Porto, Portugal... Nobody else growing on the same side of the building, but there are only 2 other apartments on this side, of which one is empty and the other an elderly couple, so not much to go on. Winds are not extreme — it's an elevated part of the city so the wind can get up a little, but it's not a protruding balcony, it's inset into the building so it only has the front exposed, sides are enclosed, so wind protection is decent Bouganvilla is seen a lot here, probably a bit further south than me mostly, but could be a good option — one point I left out is that there's an inquisitive 1-year-old to contend with (hence the original aversion to cactus), so something without thorns would be preferable, though I could elevate the pot so it's starting from a higher point anyway