how many plants before co2 is needed?

[UnarmedCrayon]

Hey all, I've read up a bit on using co2 for planted tanks, but no real explanation for figuring out just how much plant life is needed in a tank in order to require a co2 setup to thrive?

Here is a pic of my current community tank, its a 45L. Should I be thinking about co2 at this point?

 

[Billbug68]

Amount of plants is not really as important as amount of light. High light setups require co2. Now if you end up having a lot of plants, then you'll have to add more fertilizers to keep up with their needs.

 

[20cc]

depends what kind of plants you want to grow. low light plants dont need c02 , you can just dose excel and be done . there are very nice plants for low light setups . if you want to grow the fancier red plants and harder to grow ones that require high light then you need to get pressurized co2.