Cool idea. I'm guessing most of the value to your users is in the content in your app since the hardware can be replaced by bookmarks for those have >10 or so plants.
For me, I'd more excited about well organized plant content than the NFC hardware. Is there a preview of the content itself? That's where I imagine most of the "features" will be.
For me, I'd more excited about well organized plant content than the NFC hardware. Is there a preview of the content itself? That's where I imagine most of the "features" will be.