When legal, they would have freedom to choose exactly how their plants are prepared. Either by growing themselves or purchasing from a legal business. The best dispensaries test and certify their plants as organic. It's the free market at work.
Government should have no damn say in what plants you grow for your personal use. The current guilty until proven innocent policy is against the word of God and it's no wonder we have lost so many freedoms because of it. Next time the IRS combs through your personal life or emergency cash is taken from you until you can prove it's NOT illegal, thank the drug warriors.
And God said, Behold, I have given you every herb bearing seed, which is on the face of all the earth, and every tree, in the which is the fruit of a tree yielding seed; to you it shall be for meat. Genesis 1:29
And God said, Behold, I have given you every herb bearing seed= Food.