I am not very good with White Widow , at least 20 crops , and never lost a plant yet. So if you have grown more crops , I'm sorry.
Now I only get .468 grams per watt pre month.
A expensive ph and ppm meter is the cheapest way to grow. Even then calib. it every week , with lab test samples.
Now trimming them to fit the lighting area, is important so you maximize the total light. I use the FIM the first 3-4 nodes , then the headge clipper to a given size.
I use about 5.6 to 5.2 ph and 1000 to 1200 ppm over background water. Plain tape water, works great , I have used eco grow and eco bloom for decades. tried other brands and they did not come up to Eco . Note system is automated so I have a real stable growing system. Its so stable you can run it over the internet. Relayrunner soft ware on a old 486 computer.