You need to match your tank specifications to the type of plants you can keep. So we need to know how many watts of light you have above your tank and how big the tank is.
From this you can then select the type of plants that you can keep.
Generally CO2 is not required in tanks under 2watts per gallon i.e 60Watts of light over a 30 gallon tank.
If you want to really get into planted tanks you can upgrade your tank to grow just about every plant available. But be warned, it can become expensive once your addicted to creating the perfect planted tank.
So first things first, whats your current lighting and size of tank?
Then we can sort of your plants, fertilising routine etc...
Only look at the following link if you wish to get addicted to planted tanks, and throw endless supplies of money into your tank
Dont look... ah go on.
Paul