Posted: 22/09/2013 at 09:26
Two things. You mention "lawn grubs" and "little mounds"
I think you may simply be talkIng about little mounds of soiI on the lawn....these are worm casts....worms coming to the surface of the lawn. Just brush them off with a stiff broom.
Or, you may be referring to leatherjackets......larvae of the crane fly/daddy long legs. You can buy lawn grub killer to use right now. Organically you can cover areas of the lawn with canvass or dark plastic. Leave overnight. Next morning these grubs can be seen so,pick them off and destroy.