This farmer claims it's about 50% of his costs. There are more steps before it hits store shelves. And price-charged is necessarily over costs for any non-failing business, so 50% (let's say) of costs won't equal 50% of the wholesale price even before shipping, storage, and all the profit and overhead of those are factored in.

Plus, the same farmer said stuff like:

"After all, he says, he cannot raise his price on a box of asparagus by 50% just because it was cut on a Sunday."

Which makes me inclined to take anything he says about his business or this law with a grain of salt(ed & peppered grilled asparagus... mmm, delicious). Because that's both a blatant math fail, and a business-sense fail.