Populate isn't that great of an ability in this deck. Sure, you have tokens to copy, but take Wake the Reflections as an example. At best it will copy a 1/1 flyer. Is that worth a card in your deck? If you're populating 5/5 trampling Wurms it is a whole different case, but a 1/1 flyer? And it's even worse, because it's a conditional 1/1 flyer (you can have boardstates where there's nothing to copy).
Therefor Growing Ranks isn't that good either. Add to that the fact that it doesn't do a thing the turn it comes into play and it becomes a card I wouldn't run in this deck as well. And four copies of it seems like overdoing it a lot.
If you really want to go down the populate route you should make it a white/green deck I think. If you want some inspiration you might want to take a look at my Populate deck:
http://deckstats.net/decks/2657/66487-selesnya-populate-deck-rtr-cas/en. It's a budget deck, so don't expect big trampling Wurms there as well, but it is quite streamlined at the moment and it abuses the populate mechanic quite well. Good luck and have fun!