The little sticker on the apple.
If the code is four numbers, the apple is considered 'conventional'. It's not certified organic. Unless you got it from a trusty, local farmer, it was grown using some form of chemical.
That chemical is probably harmful. That chemical was a reaction to mono-cropping, ignorance, and greed. That chemical isn't just one chemical, but a thousand black magic potions copyrighted and incorporated.
Back to the sticker number thing...
If there are five numbers on that apple code, then that first number is always 9, for some reason. *
Before the invention of synthetic fertilizers and pesticides, all gardening was organic. No label necessary. The best stuff comes from nature.
Forget chemicals! They're expensive, complicated and they suck!
Organic gardening is simple. It's healthier for you and the planet. If you're in Canada, it's healthier. If you're in Kenya, it's healthier. If you're here, you probably want to do your own thing.
What do you want to grow?
* My favorite number is 9 because I was 9 in 3rd grade and that's when I decided 9 was my favorite number. If you went to public school in the U.S., you might have been 9 in 3rd grade too but you may have been 8. I don't know why 9 is the organic sticker number.