Your asking for magic to make plants better ok here's the spell: spend a extra 45 min per day then normal with or working on plants. You will get 20% more yield. Now for the hokey witchdocktor math that's more true then some, in that 45 min per day you will exhail some co2 the plants will enjoy, an your very likely to see more wrong with the plant when your bored but spending time then rushed to get done. Draw the plants whatever they have a lot to teach so get ready to learn.
Basically I'm saying the time an effort can't be beat, use folier feeding, remove dmged leaves, feed correctly and grow best weed Eva!!!