"6 Day Delivery"
Now, I'll admit that this is probably just me, the grammar geek, but I'm pretty sure this isn't what they mean. Let me explain.
What the establishment wants to convey to its customers and the public at large, is that it delivers fresh produce six days a week. Maybe if they'd added "Monday through Saturday" it would have helped somewhat.
However, due to the way this is phrased, what it's really saying is that it takes them six days to deliver their fresh produce. Hmm. Fresh isn't exactly fresh if it's been sitting on a truck for six days. Amazon offers 2-day delivery, UPS has 1-day delivery, but fresh produce should hopefully be speedy.
So, be careful with your phrasing. Say what you mean, and mean what you say, or people like me will love the opportunity to write a strongly worded letter to tell you it's wrong.