SOIL Low pH issue, interested in a second opinion on how I plan to remedy the impacts

[DutchTreatMaster]

I have put these plants through just about every type of challenge, and I am hoping the last one I need to resolve is pH. In general, when I water with Fox Farm Nutrient Trio(week 3) the pH is about 6.5, and the run off is about 5.5-5.7. I am planning to address this with pH up to make the water about 7 prior to watering.
I have two issues I am worried about that likely resulted from the pH problem: 1) The leaves are light green, and 2) I keep getting blotchy brown spots on the leaves that ulitmately lead to them yellowing and dying.
Once I correct the pH issue, I am assuming I need some more nitrogen to address the light green leaves, and maybe a manganese issue for the blotchy brown spots? Planning to add more grow big(2.3 tsp rather than 1.5 tsp) to my week 4 nutrient mix than usual in the next watering.

I would really appreciate feedback to whether I am diagnosing the issues correctly and whether my planned corrective actions make sense.
Thank you!

[SoOrbudgal]

Hi there poor sic gals you have. I was looking back at your privious grow what's different now? Are they sucking up old feedings? Too small a pot? Sure don't look like plants you grew before and in different pots?

[DutchTreatMaster]

Key differences between this and first grow:
type: 1st blueberry cheesecake/dutch treat; this time Purepowerplant, papaya
time of year: winter grow this time versus spring/summer
smaller pots(3.75 gal versus 5 gal): intended to do a quicker grow, but struggled to keep them healthy during early veg. Intended to be almost done so I could start some plants I want to get outside in May. The reality is these are now going to veg until my outdoor plants are ready to go outside since they need to share the same light/tent.

Mistakes made this time and corrected since:
- started seedlings in natural light not realizing winter time sunlight would make them stretch
- didn't realize cold basement would cause issues
- didn't realize how dry the forced air heat would make it, and hurt the plant
- didn't start feeding until month 2

I will stick with normal water and give it a bit of a flush and let it dry for about 3-4 days. I won't add nutrients maybe for another week.

Thanks for the advice!

[Canuck147]

Budgal is right - give it just plain water with a pH between 5.5 6.5 - and don't worry about the runoff.

To me it looks like nutrient lock-out. Give it the plain water to clear out residual juju juice left behind and let it dry dry dry out.

[DutchTreatMaster]

Thanks will do a flush next watering and go back to regular nutrient schedule. Won't up strength quite yet.

[Farmbuck]

I agreed with Budgal and Canuck.

[DutchTreatMaster]

Budgal is right - give it just plain water with a pH between 5.5 6.5 - and don't worry about the runoff.

To me it looks like nutrient lock-out. Give it the plain water to clear out residual juju juice left behind and let it dry dry dry out.

So I flushed the plants with plain water and gave 3 days to dry out. Just watered with nutrients that I used pH up on to get the water up to 6.75. The runoff was 5.5 on one plant and 5.4 on the other. That seems like a huge difference. I'm thinking of going up to 7.0 for next few waterings to hopefully get the root pH up. At a curiousity, why did you say not to worry about the runoff pH? I was taking that advice for Nebula's video on pH. Here are the latest pics, still not looking so hot

[Canuck147]

Cuz I've never checked my runoff - that's why I say that.
Looking kinda droopy - 3 days to dry out wasn't nearly long enough - they are looking half drowned.
Cannabis plants can only absorb nutrients they are being feed when the pH is between 5.5 - 6.5. If you water at 7.0 you are risking nutrients lock out.

[DutchTreatMaster]

Okay thanks. I was following the advice at the bottom this article to fix my root ph. Made me think watering up to 7 was okay.

https://www.growweedeasy.com/flushing-sick-cannabis

I appreciate the quick responses. Helps to bounce ideas off people!

[Rwise]

I use wood ash in the pot to raise PH and feed the plants, just sprinkle some over the soil and water. Then monitor the PH