Leaves turning rusty, tips curling downward

[tripin420]

SOIL GROW - 1kw - HPS for flowering, MH for veg

Strains: Wreckage, Heavy duty fruity, Grape stomper x og, juicy fruit, heavy duty fruity
Hybrid, unknown %
12 plants, put into flowering 3 days ago
Using FF ocean forest and FF light warrior in a 2:1 mixture in 3 gallon pots
Temp: with light on 83, spikes to 90 while the co2 is on and fan off
RH: around 30% all the time
pH: some as low as 6.1 or 6.2, most around 6.4-6.5
pests: had spider mites a few weeks ago, treated with pure kapow, have gnats currently
watering every 3-4 days, whenever they need it
FF grow big, big bloom, and tiger bloom nutrients used at normal strength following the FF feeding schedule
Grow tent is 6.5' x 6.5' x 6.5'

Problem: a few leaves on about half of the plants have started to curl downwards, like an eagles talons, and now are starting dry out and become rust colored

 

[Marzbadrock]

What's the pH of your soil?

 

[PeytonManning]

I would add some cal/mag and raise your ph. I believe it's supposed to be around 7ph for soil

 

[tripin420]

yeah i had thought the range was like 6.2-6.8 for soil but i need to re-check on that...the soil pH was around 7 and i had been purposefully lowering it to get it around 6.5

now im thinking the ones that are hurting are probably at 6.0 and the ones that are still okay are at 6.5

they are dry now, gonna get clear water tomorrow...i was thinking about watering with 7ph water, as that will raise the pH levels a bit...i need to get a new co2 tank tomorrow so ill grab some cal/mag while im at the grow store if after some research, that turns out to be the issue

im also thinking i need to calibrate my water pH tester....very possible its off

 

[PeytonManning]

I think soil ph is 6.5 to 7.5, the lower 5.8 to 6.5 are for hydro. It looks like it could be a boron deficiency, but those are rare, but could be caused by nute lockout due to ph. Definitely calibrate meter though.

 

[tripin420]

from what im reading anywhere from 6-7 should be okay, with optimum levels at 6.5 and hydro from 5.5-6.5 with optimum around 5.6 or 5.7

so on a few plants they are gettin close to the bottom of that range but still in it....idk its confusing. maybe i shouldnt have bought the cheapest meters i could find lol

 

[Marzbadrock]

How are you testing your soil pH? Runoff? PH soil probe? You want your soil pH to be 6.5

 

[tripin420]

soil probe, but the soil is too dry to test now

 

[PeytonManning]

Yeah, you'll need a digital one. Then you test and adjust the nute mix ph, and then check ph of runoff. That'll help you get a better idea of what's going on with your girl

 

[tripin420]

i have a digital water ph tester that is probably not calibrated, i have a probe that does soil that is probably okay, but i didnt check every pots pH, just a few and they were 6.0, 6.1, 6.5, 6.5, and like 6.3 and im not sure if i got the ones whose leaves are changing or not

 

[tripin420]

also because all of those were in the range, tho on the low side, i figured they were fine, and to water with 6.5 next watering to bring them up or keep them the same