HELP! Some leaves turning yellow with brown spots

[Sourmug]

Hello Gurus,

It’s my second grow and I think I may have a deficiency? The one on the left is Blue Dream CBD and the other is Tropicana Cookies. Both feminized photoperiod.

Germinated with paper towel
Seedlings in solo cups with Happy Frog
Transferred to 5 gal fabric bags with Ocean Forest
Currently in week 12, flipped to Veg last week

The only change from the first grow is the Happy Frog

Using distilled water

4 x 2 tent
Spider Farmer SF200 LED light

Light distance around 18”

I don’t understand why one plant seems worse than the other. Any advice would be greatly appreciated

Thanks

[OldManGrower]

Your PH is incorrect. It should be about 6.8+/- Distilled water contains absolutely no minerals. Get a PH meter some cal-mag and most likely some nutrients. My guess is your ph is way too low.

[Sourmug]

Thanks! Waiting for my new PH pen to arrive and will test the run-off water level, unless there is a better way to check PH in soil? I have a jug of CalMag as well as the Fox Farm nutrient trio. Will pick up some PH up/down today also

[SwitchH2O]

Just my 2 cents, but your PH should be at 5.8 during veg cycle and 6.0 during flowering... if you want to be exact. It's all about your plant up taking the nutrients in your water. I would flush those plants out. Run RO PH adjusted water until you get about 20-30% runoff (water coming out the bottom) Measure the PH in the run-off until you get the 5.8 to 6.0 range. You could be suffering from nutrient lock-out, which happens when salts.... bla bla bla... you can read about it on Grow Weed Easy. PH in tap water usually sits around 7.0, so just using tap water alone will cause issues. You'll need some PH up/down to adjust the water.

SwitchH2O
_______________________________
4’x4’x8’ frame built grow room
Spider Farmer SE3000
4” Vivosun powered intake
8” Vivosun outtake with 8” Filter
RDWC (Recirculating Deep Water Culture System)
Rockwool starter with clay pellet medium
Combination of Remo, Advanced Nutrients and a proprietary blend.
2nd last grow - 19.98% THC
Last grow - 22.23% THC

CURRENTLY GROWING
White Tahoe Cookies - 3rd week of flowering

[Bowhunterwoody]

That pH seems low for soil. 6.5-6.8 for flower is what I've read and use. A little lower for veg. The #s you mentioned sound like coir pH levels.

[OldManGrower]

I believe, if I am correct you are a hydro guy and Sourmug is in soil. Soil uses a higher ph norm than hydro.

[Sourmug]

Thanks for all the great advice. Got a new PH pen, calibrated it and checked the runoff. It was indeed low, around 5.8 so, bought some ph up/down. Our tap water is at 7.2, was thinking of using that and adding some Cal Mag to get the soil back up