I have done it with both duration and intensity, as well as each individually, and I think it’s a good idea if running a homogeneous garden. Otherwise it’s kind of difficult and possibly counterproductive in a multi-strain garden or perpetual flowering room. In those cases it’s best, like St. Phatty says, to move individuals off to the side. Even into a shadowed area.
§467. I am sitting with a philosopher in the garden; he says again and again “I know that that’s a tree”, pointing to a tree that is near us. Someone else arrives and hears this, and I tell him: “This fellow isn’t insane. We are only doing philosophy.”
― Ludwig Wittgenstein, On Certainty