Planted Tank Guru
Join Date: Jul 2008
Location: East Lansing, MI, USA
The question is valid. The answer can be very complicated and confusing. Or simple.
Any light that will produce sufficient PAR (photosynthetically active radiation) will grow plants.
Ignoring the evaporation, a 96 watt actinic on a 10g tank probably won't grow anything a freshwater plant enthusiast would want to grow and look at.
So, yes, a 36 watt of the wrong temp (degrees kelvin) could be way off.
Hoppy's chart has gained wide acceptance here and while it does mention wattage, the more important part is low light, medium light, and high light for a given combination.