kkaazz2 , I had similar discolouration on middl
e/high-middle leaves during my last grow of White Shark in DWC. It might be hard to see in this pic, which has been colour corrected for HPS, but your description is very similar to what I was having going on.
These were clones I purchased from a Canadian Licensed Producer, who told me that this strain was a "light drinker." I didn't make the likely connection between the leaf issue and my overfe
eding (EC too high ... I think
Campesino pointed to this possibility earlier). Rather, being the noob that I am lol, I immediately started down a path attempting to identify and "correct" some deficiency. Here is the entry from my journal (on another site) that lays out the issue I was having:
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UPDATE: Nute Lockout??? ... End of Wk 3 Flower (End of Wk 4 of 12/12)
Observations:
- I noticed what I thought was some nutrient deficiency about 7-10 days ago ... there was also a very small amount of nute burn (see previous posts)
- Mostly affecting middle growth ... tops of colas are fine; no problems I can see with roots
- TDS at beginning of week was ~1400; after 3 days it was up to ~1550
- pH at beginning of week was 5.8 (nutes mixed well before install ... I went with 5.8 because I was noticing a trend of it moving upward and needing to be adjusted down after install)
- pH was 6.3 after 1-2 days; brought it back down, and within 1 day it was back up to 6.3+
Assessment
- I considered temperature, RH, air movement, and nute excesses/deficiencies, but in the end I think this is ...
- Nute Lockout (which can be confused, apparently, with nute deficiencies by noobs like me!)
- I also understand this needs to be corrected urgently, so ...
Response
- I dumped rez and replaced with 10 gal of RO + Clearex (@ 10 ml/gal = 100 ml), balanced to 5.9; TDS = 50 ppm
- Circulated Clearex solution for 2 hours, as per directions. Hit the 20 min manual watering 3-4 times during the 2 hrs
- At end of 2 hrs, TDS had risen to 320 ppm and seemed to be holding there
- Dumped rez and replaced with 9 gal of RO + Sensi CalMag Xtra (1 ml/L) + Revive (2 ml/L), balanced to 5.8; TDS = 420 ppm
Re-Assessment
- TDS went from 420 to 450 over the past 24 hrs. I think that is good ... meaning there is no more excess salt to leach?
- pH went to 6.3 after 12 hrs; brought it back down to 5.8
- after another 12 hrs it was back up to 6.2; brought it back down to 5.8
Plan???
- They're now starting Day 2 of the RO+ flush
- Rez change is scheduled for tomorrow (Start of Wk 5 BCNL base nutes ... meaning decrease in N and increase in P-K
- Concerned that pH continues to rise
- Do another Clearex flush for 2 hrs???
- Use Flawless Finish instead for 2 hrs???
- Dump current RO+ and replace with fresh RO+ for the next 24 hrs prior to rez change tomorrow???
- Leave it as is, then do rez change tomorrow???[/TD]
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Unfortunately, I didn't receive any suggestions/guidance for what to do from there. So, I moved forward assuming I was dealing with nute lockout, and looking back I think that I was. After doing the flushes described in that journal entry, I returned to the feed schedule @ 75% strength. Here are the next few relevant entries, so that you can see what I observed and what I did from here:
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UPDATE: Nutes UN-locked??!
- Here are the Sharks a few days into Wk 4 Flower (Wk 5 of 12/12)
- I think the 2-hr Clearex flush followed by 2-day RO flush have "unlocked" the plants ... no signs progressing leaf damage ... might have caught it just in time
- The TDS has remained steady or even dropped a bit since I put in these Wk 5 nutes (@ 75% strength re lockout/flush) ... whereas over the last 2 weeks the TDS has been creeping up each day
- Buds are starting to swell up a bit; getting frosty; smelling goooood![/TD]
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UPDATE: Nearing End of Wk 4 Flower (Wk 5 of 12/12)
- Sharks continuing to plump up and getting super sticky!
- TDS was starting to creep up (not crazy, just 100-150 up from start of week) as they drank water during the week, so I added a few gal of RO + CalMag
- pH seems ok ... letting it drift from 5.8 to 6.4 then I adjust it down (have done that once since start of week)
- I may do another flush before installing Wk 6 nutes ... maybe just the RO + Clearex for 2 hrs ??[/TD]
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UPDATE: Start of Wk 5 Flower (Wk 6 of 12/12)
- Did a 2-hour rinse with Clearex (10 ml/gal) + RO (ppm at start: 50; ppm at end: 250)
- Then installed Wk 6 Nutes
- Last week, I did the same but added a 24-hour RO+ flush after the Clearex rinse because I was responding to nute lockout
- This week, I'm just doing the rinse as an extra caution ... although I think I might start doing this weekly with this strain
- Buds starting to fatten up; Wonderful aroma; Incredibly sticky[/TD]
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This was my first time growing this strain, and now I appreciate that 1250 is likely the upper end of what I should feed them. For the remainder of this grow, I did a 2-hr Clearex flush each week before installing the fresh nutes. I'm not sure that will be necessary if I feed properly from the start. Nonetheless, with my plants currently in veg (2 weeks post transplant from cloner), I decided to do a 2-hr flush before their last nute change. If I'm not seeing any issues, I think I'll do it every second week.
That grow really helped me SEE the connection between EC and pH. Once I got the EC in the range the plants wanted, the pH was stable and drifted slightly as desired.