How do you eradicate poisons, be it RoundUp, Grazon or even nuclear fallout, from you gardens so that you can actually grow food in an SHTF situation? It takes time but its actually pretty simple.
"The time for war has not yet come, but it will come and that soon, and when it does come, my advice is to draw the sword and throw away the scabbard." Gen. T.J. Jackson, March 1861