still not enough light city...
a 42wCFL only puts out about 2600 lumens on its own. the more lumens, the better...as long as your temperatures aren't being affected too much by radiant heat.
u said you're only growing one plant...well i'd say go with at least 4, maybe 5 of those buggers. go to a good sized hardware store, LOWES or HD, and read the back of the packages about luminosity and spectrums of light for each bulb.
when vegging, u want a more BLUE spectrum light, still lots of it, in the higher frequency range (4000-6000). to flower, switch over to a lower frequency bulb (you still want to at least maintain the same amount of LUMENS, so don't use less light) in the 2000 range.
read these:
https://www.rollitup.org/general-marijuana-growing/723-things-know-about-lighting.html
https://www.rollitup.org/cfl-growing/107992-tutorial-growing-cfls.html