It’s only a little bit of a stretch - if the landscaper buys fertilizer or tools from a supplier in another state, I’m sure they are participating in interstate commerce and at least the person doing the buying is covered by FLSA. But I’m pretty sure that they aren’t if they buy those tools from an in-state supplier even if at some point they came from another state - and I doubt many landscapers with revenue under $500K are buying tools and fertilizer from out-of-state rather than a local Home Depot/ACE/True value sort of place that offers a contractor discount.
BTW,the wheat wasn’t grown in a backyard- he was a farmer who was permitted to grow about 11 acres of wheat under the regulations. He instead planted 23 acres , which he did not sell but used to feed his own animals rather than buying feed. Whether one agrees with the decision or not, it’s not as though the court said that growing 100 square feet of wheat in your backyard for your family to bake bread with constituted interstate commerce.
It goes beyond that. Growing your own pot is illegal (federally) because no matter what you do with your home supply, you are by similar logic affecting the interstate market of an illegal substance.
When SCOTUS ruled in favour of the constitutionality of the ACA as a tax, it explicitly said the “interstate covers everything” logic did not apply, was incorrect. This was sort of snuck into the judgement as the first serious limitation I have heard of regarding the scope of the interstate commerce clause.
The scope of the Commerce Clause - which is extremely broad and determines whether Congress has the authority to regulate things - is not the same as the scope of the FLSA. In other words, while Congress could regulate the hypothetical landscaper if it buys products made in other states, it hasn’t. The FLSA only applies where the employer’s own business activities are interstate.