I have fishlessly cycled a number of planted tanks and always set them up, planted them and then begin the cycling with ammonia. The thing is the plants eat ammonia which is why the more high tech planted tanks will often have 0 nitrates and one must actually add them. because the plants in them consume the ammonia, there is almost not nitrite and no nitrate. plants can use it all.
In a more moderately planted tank, the kind most folks will have, then the plants will consume some of the ammonia but not all. The rest will go for the needed bacteria. However, due to the plants, the size of the bacterial colonies will be smaller than they would were there no plants.
If you cycle the tank without the plants and then add them what will happen is some of the bacteria you worked to establish will die back when you add the plants which will then begin to consume some of the food that would be available to your bacteria.
Normally one can expedite a fishless cycle by raising the tank temps into the mid 80sF (about 30C) or more. Most plants wont be happy at these temps which means you cant do the temp raising while cycling a planted tank with ammonia. However, the fact that the plants assume some of the work of the bacteria means you need fewer bacteria which means it takes less time to reach that number.
