The grower's question was: "Just trying to learn here, with coco how do you get them to decide to change up what they will absorb?"
Instead of LMAO, why don't you tell how plants can decide what to take up? (like the plant has a brain...).
A plant can only take up what is available and doesn't "decide" anything. If that were the case then we'd never see leaf tip death from too much nitrogen as plants would decide they have enough and stop. There's no decisions being made. If you over fert your plants, they will die, pretty simple.