I have a couple of white widow plants that grew together from seeds. It has been in veg for about 4 weeks. The leaves on bottom are starting to yellow. I looked iit up and found that its either ph or nitrogen. My ph meter reads 6.9 to 7.0 ph. I have been using a ph down to get the ph down. I flush the soil with 12-14 gallons of water around 6.5 ph. Within a few hours the ph is back up to 7.0. I assume its because I am using the miracle grow soil. Anyway bottom leaves are starting to look pretty rough. Yellowing leaves with green veins. White holes are starting to appear on the bottom leaves.