How old do my turtles have to be to have babies?

Question

and do they need sand to lay their eggs in?

Answer 1

It takes map turtles 10 years to reach sexual maturity.

this was all i could find on the sexual maturity of a map turtle.

Answer 2

It depends on species and size. For example, common snapping turtles reach sexual maturity at 6-8 years and about the same number of inches in shell length.

Sand is good because it is easy to dig. Sandy loam is pretty good too.