I test the leaves closest to the growing veggie/fruit during the growing season to see if I am going to achieve the Brix I want for each different veggie. Then, I test the veggie when I pick it to see what the Brix is so I can make more adjustments or leave everything the same for the next season. I sometimes take the refractometer to farmer's markets and I may test a sample they have set out. I am very careful not give them any chance to perceive insult and mostly don't even let them know that I am testing. I don't take it to the grocery store because I am convinced that their produce is of the lowest Brix possible. If the tomato is beautimus looking chances are it is a market tomato, not grown in enlivened garden soil and certain growers are known to grow in a hydroponic system. I just measured a tomato from the grocery store. It wasn't bad but the Brix was 4. A good tomato should have a Brix of 8 and an excellent one should be 12. I started Brix testing because I am convinced that strong healthy plants do not attract bugs/pests/insects. Sure some things are unavoidable like a hoard of locusts or hoppers, but for the most part insects seek out unhealthy plants.
