New Grow Starting to Turn Yellow

Planted a gifted seed of unknown origin - not sure if auto-flower or not. Everything has been going incredibly smooth for the first few weeks. However, now I’m starting to see a pretty aggressive yellowing of the fan leaves.

The PH levels are 7.68, using Fox Farm soil, on a 18-hour time cycle. Any help/suggestions on why this would be?

Welcome. I would start by verifying my pH meter. 7.8 is a little high on ph I would shoot to get it down between 5.9 to 6.8

1 Like

Oh really? Ok interesting - Idk why I thought I was right in the sweet spot. I’l start stepping the PH down with some Calcium Sulfate.

Thank you for the tip!

1 Like

Yes pH of 7.68 is to high. The sweet spot I think is around 6.2 to 6.5.


I run pH anywhere between 6.2 and 6.8 during veg. When I get to flower I try to keep it as close to 6.5/6.6 as I can.


I grow hydroponically and keep mine in thev 5.5-6.0 range. I’ll even start at 5.0 sometime soon because my pH tends to rise until I swap out the water in each bucket whick I do bi-weekly.

For soil growers:

1 Like

Yep, fix your ph and probably time to start giving some nutes, it’s begging for nitrogen.