Just yesterday, for my 15th birthday I received my very first phone : D It was a hand-me-down of sorts from my mom, and since my family is wary of spending money we opted not to get 3G or 4G or anything like that (basically, no internet anywhere but my house), which is fine for me since most things I need internet for I figure I can do with my laptop.
However, one of the first things I did was download Pokemon GO! At first, I was having a ton of fun, catching my very own Bulbasaur and Ekans in my own backyard (still within range of my house's internet.) However, as I explored the neighborhood I found that I was unable to see any other Pokemon, even though I'd walked around for about an hour. Occasionally I'd see leaf particles pop up in certain areas, but they were all on private properties and as such I was unable to interact with them (without getting shot by my neighbors o_o").
My hypothesis is that the leaf patches are places where I would be able to battle Pokemon, but that I can't because I don't have internet. However, my trainer walks around on the map just fine, and the Pokemon's locations relative to me on the tracker still show up (if I move to different locations some Pokemon will move further or behind on the tracker).
tl;dr: Do I need internet (3G, 4G, whatever) to be able to catch the Pokemon in Pokemon GO? Or am I just a bad player? Or both XD I'm sorry if this question sounds silly or stupid, I have had no experience with anything beyond a basic flip phone until just this morning.
Thank you very much for your help!!