Just to make sure the OP knows what a plug is:
Buy a kit with monkey rubber strips, a rasp and an insertion tool. Clean the hole by inserting the round rasp, insert the rubber strip onto the end of the insertion tool at it's mid-point, cram the strip into the hole leaving a quarter inch or better on the outside of the tire, twist the insertion tool and pull it out. I usually trim the excess from the outside of the tire and done. The strips cold bond to the tire material and form a very good seal. We have lots of thorny plants around here, Acacia being the worst, and I probably have ten plugs in my fronts and they don't leak a bit.