I'm no expert but I've heard some bad things about borax. I searched the web for 'borax natural pesticide' and found the following.....
If there are no children or pets in the home and if birds have no access to the floor, the following mixtures can be used to kill roaches.
Mix together 2 tablespoons flour, 4 tablespoons borax, and 1 tablespoon cocoa. Set the mixture in dishes inside cupboards and behind large appliances where animals have no access.
Mix equal parts of oatmeal, flour, and plaster of Paris. Set out in dishes.
Sprinkle Borax where roaches travel.
Set out dishes containing equal parts of granulated sugar and Borax. Roaches are attracted to sugar, and the boric acid in Borax is deadly to roaches.
(Boric acid and Borax are toxic and should not be accessible to parrots and other pets. Baking soda is said to work as well as Borax in this formula and it is non-toxic.)
The laundry soap may be different. Don't know.
I do know that our roaches are big enough to drive our MH away. Art
Here's one site....