Firstly welcome to the forum....

To identify yr plants, you can goto :

www.tropica.com
or
http://www.aquaplant.org/

Since someone have helped you identified those plants, you can goto the above site to see their requirements...

You also probably need some base fert or substrate for the roots to take up certain nutrient from the substrate.

If you really do not want to inject CO2 into the tank.. you probably need to follow the Diana Walstad book titled " Ecology of the Planted Aquarium". She preach using natural way for the plants to take up Carbon, uses garden soil as base fert, have natural sun light into the tank... only does a water change every 6 months and probably can grow only slow growing plants..

You can read the reviews at Amazon.com

Photosynthesis depends on 3 factors, temp, co2 and lights... so with low or little co2, the plants might grow slow or slower.

Of coz, if too many slow plants grows in your tank and you have excess nutrient... algae will pay you a visit... The above mention book also have a full chapter that talk about combating algae in details...

Most of us probably start by using DIY CO2 using sugar n yeast to produce te CO2 before moving into CO2 cylinder...

Hope this helps to get you going...


Stanley