A common misconception is that high light makes plants grow well. A balance of lights, CO2 and nutrients is what's needed to create a successful planted aquarium. The key to a great planted aquarium is making light the limiting factor. Many aquariums have plenty of light yet neglect CO2 and nutrients, leading to algae issues. Ideally, the CO2 would be able to easily keep up with light over the aquarium and nutrients would be sufficient to allow plants to grow healthily.
You can create an excellent natural looking aquarium with little light, you just need to select appropriate plants, mosses, java fern, etc. But you mention you want a carpet, in which case you may need to upgrade your lighting. Just keep in mind that balance is key.