why plants usually grow better when they are given fertiliser?

Answer 1

because it has nutrients that plants need to grow well.

Answer 2

Also to be more specific, the chemicals that are in fertilizer - usually phosphorus, nitrogen and potassium - are usually the limiting nutrients in the soil. Most of the other nutrients a plant needs like carbon and oxygen it can get from water and the air.

Answer 3

fertilizer is the essential nutrients that the plant needs to grow big and strong that they sometimes lack from the real world. you can almost consider fertilizer for plants what a daily vitamin does for humans.