Posted: 10/06/2014 at 07:26
Googling Cornmeal Gluten comes up with this
suggesting that it has been marketed as a pre-emergent anti-weed treatment - however the efficacy seems unproved at the very least.
I presume that Rosemary Freeman is in the USA.
As for the garden - the first thing to establish is whether the weeds are originating from below the weed barrier and growing through it - in which case it needs replacing with a better quality membrane - or whether the weeds have their roots in the soil above the membrane - in which case the answer would seem to be consistent weeding.
It may well be that weed seeds are blowing in from elsewhere - it would be helpful to look around and identify a possible source of weed seeds - if these could be eliminated it would be helpful.