save that seed she is a female stress seed if she has not seen pollen. Hemies get male flowers and will be yellow and noticable. You may have had a stress in the light cycle maybe when switching from veg to flower. Not always a bad thing and is how people make femalized seeds. I water everyday with a garden sprayer but every three days is alright if you dont have the time or hundreds of plants. I feed them at a constant ion consentration everytime to reduce stress. I only use 100ppm when your numbers are correct. Say if I was using earth juice I would use 60ppm grow 15ppm bloom 20ppm maxicrop and 2 ppm thrive alive green. You will not get a single yellow leaf if your conditions are correct(keep above 45F) and you will not need to flush just stop watering a week before they are done. I fed thousands of plants this mix from veg to flower and never switched numbers from veg to flower to reduce stress and promote growth. I grew single cola foot tall solid flowers with supercropped lower stems the size of my thumb. I have to leave yet another state right now but soon enough the fam. will be back. That is all they need and taste so good.
One love
c