A 1 litre container of 360gm/l concentrate claims to treat 3000 sq metres

so that is 120mg per sq metre. The amount of water you use really
depends on the method of application so long as you deposit the required
amount of GF.
More stubborn weed need higher concentrations so you can scale up
accordingly.
hth
Bob

Pete C wrote:
Having read the post about GF in France, I wondered what the concentration
should be for actual 'effective' use........Gm/Lt ?