Isn't this exactly what we are currently doing?
The feds go quite a bit further, especially regarding the medical marijuana issue, where the pot does NOT cross state lines, and regarding cultivation for personal use, where no commerce occurs. And the judge recommends that the feds REGULATE drugs, not issue idiotic blanket prohibitions that usurp powers that should be left to the states.
So, wouldn't you then conclude that cultivation for personal use interferes with interstate commerce because, as a result, no commerce occurs? Just a thought.
You're saying that growing your own has no effect in interstate commerce. Sure it does. Affects intrastate commerce, too.