Will plants grow best if watered with water or milk?

Definitely water. Plants don't have a need for milk. Good luck

Water, which is why it doesn't rain milk.

Water of course. Because milk contains fat and lactic acid and hence, minerals and other nutrients plants require will not easily dissolve in it. Instead, they will better mix with water. Plant cells including roots are not built to absorb a thick substance like milk or digest the milk nutrients.

i did that 4 a science project when i was young the plant i watered with milk got nasty and moldy

H2O

water

I have heard that whenever the plants turn yellow, you could water it by a little ammount of milk. On the other hand, i have seen my plants died 2 days after i water it by milk ^.^

Water. Milk might also entice herbivore mammals to eat them -- especially young mammals that have just been weaned!