I think it would be useful to have a way to get Barley seeds other than punshing grass.
You already added a Recipe to convert Wheat into Seeds so I think something like this should be added to iguanaman.hungeroverhaul.module.ModuleNatura:

GameRegistry.addRecipe(
 new ShapelessOreRecipe(
  new ItemStack(NContent.seeds, 1, 0),
  new ItemStack(NContent.plantItem, 1, 0)
)); //1 Barley -> 1 Barley Seeds

edit: The main reason for my suggestion is that on left click fully grown barley only drops barley and no barley seeds the same way wheat does. If the barley isn't fully grown it does drop one single barley seed, so there is no way to multiply existing seeds. It seems like cotton has the same problem but I didn't test it enough to be sure about it.

Isn't the wheat -> seeds recipe from vanilla Minecraft?. Not sure why this should be implemented by HO instead of Natura.

EDIT: Never mind, didn't realize HO added that. Ignore me.

@progwml6 / @Parker8283: Thoughts on this?

Better late than never :P

Makes sense and seems fair. I say add it.