Could be. Here's the scoop. The case I was thinking of concerned a New Deal farmer growing a crop over his quota and feeding it to his chickens.
It seems that they have stopped at banning home gardens, solar panels and garage sales and maybe by daughter's babysitting.
That would be Wickard v. Filburn, which IMHO marked the death knell of the Tenth Amendment and the end of limitations to federal powers. I had some hope that the current Court was working to roll it back, with rulings like Printz and Morrisson, but Gonzales v. Raich put an end to that. I'm terribly disappointed in Justice Scalia. Justice Thomas is the last true hero on the Court.
Yes. It's illegal if a judge says it is: to grow any plant not explicitly stated as legal to grow for personal consumption, in a legally proscribed quantity, with legally proscribed restrictions on the rights of the grower to gift the crop to a neighbor. The mere ability for the crop to be part of a economic transaction, or to be passed across state lines, is all the justification needed for the federal government to make the growing, packaging, transferring, gifting, selling, transporting of a crop illeagl in the US today.
This is a liberal interpretation of the ruling, it could explicitly prohibit the growth of all crops without government granted priviledge, as the decision was written.
Wheat and marijuana are illegal to grow for private intra-state use, according to the Raich decision by the supreme court, delivered earlier this month.
Google "Raich Ashcroft" for more info.