What type of timber for a garden bed?

[yana]

Hi , I want to build garden bed but I don’t know what kind of wood or timber I should use . I looking for wood or timber that has chemical  free and last long in outdoor ?!!! What’s post should I use on edge of bed ???
please help !!!!!!
thanks

Community manager's note: Check out How to choose the right timber for the job for expert advice.

 

 

[Divaneh]

Thank you!