Eli5, how do selective herbicides such as broadleaf weed killer work? Why do they only kill certain things?
In: 46
There’s a couple of different ways that herbicides and weed killers are made to target certain things.
1. Most weed killers are root poisons. Weeds are short lived and don’t need extensive root structures for long term energy storage; they only grow enough roots to hold themselves up. So you make a poison that’s strong enough to take out their limited roots, but not strong enough to do significant damage to grass or other plants with more extensive root structures.
2. Most poisons are absorbed thru the roots, but can be designed to be applied to the leaves instead. Weeds and grass tend to have different types of leaves, so you make a poison that is better absorbed by one type of leaf. Everything gets the same dose of poison, but certain kinds of weeds absorb a lot more of it, so they’re the ones to die. Your broadleaf weed killer is probably this type of poison.
Latest Answers