Plants that don’t have to struggle don’t grow strong. While you might want to give some plants a good start by growing them indoors for a while, many plants won’t end up nearly as strong or impressive if you don’t put them outside where they must weather the elements. Some plants will even be useless for their intended purpose if they grow up too soft.
An oak tree will not grow big and strong if it doesn’t have to. If God didn’t send us trials now and then, we wouldn’t grow either. You don’t get stronger without weathering some resistance.