as Rex already posted, it's enough to grow all plants in a very healthy way.
however some plants may not produce desirable growth without more light.
for example; Glossostigma may grow vertical instead of horizontal, and some
plants won't show off their red shift coloring until they are closer to the light.
keep in mind that over the bulbs life it will dim considerably, so a year from
now you will actually have 2.0wpg burning over your tank. this does not
mean you should run out and buy more lighting, I just post this so you have
realistic expectations when choosing which plants to populate your tank.