Kind of an old post but.... I've used ironite with great success. Only the granular and yes, it takes time. I have never used the liquid, but will be doing so this weekend on my front yard. I have also, in the past, used actual IRON shavings. If you have a machine shop near you, ask them to sell you the shavings (dust) from thier brake lathe. Wash it and use a magnet to pull out only the iron. (You don't want any grease or brake pad dust in the mix.) It works GREAT and lats a LONG time. If you have pets or kids, don't use these shavings!