I grew white widow on my last indoor grow. 5 gal pots 400 watt lamps, organicare soil. I found that WW does not like the same level of nutriants that my other strains could safely take and would 'lock out' if over fed.
solution: flush thouroughly with ph adjusted water to rinse out the surplus that has built up in the soil. I do not have a ph meter, just simple cheap test strips that are as acurate as any meter, and a lot cheaper. (available at walmart, or any nursery. First check your water supply for ph. (I have a well that delivers constant 7.0) I had to buy some ph down to bring it down to the desired levels (5.6 - 6.0)
If you use city water check the ph on a regular basis, as the ph can vary quite a bit depending on where you live, time of year, and water company fideling with it. Also city water adds chlorine and other 'stuff' that may affect your plants health. Not much you can do about that. Maybe let the water sit for a few days to allow the chlorine to evaporate befor giving it to your plants.
White Widow can be a bit fussy, I had to flush twice durring my grow as lock out was a major problem. Simply take your plant outdoors ( or even in your shower) and run about 15 to 20 gallons of ph adjusted water through the soil.
All in all white widow is a good strain, pickyness not withstanding. I grew mine to just over 4 ft. and with 7 plants I harvested just under 2 pounds.
Good luck with yours.