Started getting brown tips about 10 days ago. Thought it was nute burn and backed ppm from 900 down to 675. pH at 6.0. Then brown spots started on two leaves this week…In 3rd week of flower and growing in December under 1000watt led. Humidity got down to 20 and up to 55 this week. Temp 65-85 air and 68 water. Thanks so much in advance for any help.
A photo in natural light would be better for us to see whats going on @SCunkApe 
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Would be helpful if we could get more info:
Strain; Type, Bag seed, ILGM… name of strain:
Age from Sprout:
Soil in pots, Hydroponic, or Coco / Brand and type of Soil & Size of Pots:
How often do you water and how do you determine when to do so?
PH of water and runoff or solution in reservoir:
What is strength of nutrient mix? EC, or TDS:
Indoor or Outdoor:
Light system, size and height from plants:
Temps; Day, Night:
Humidity; Day, Night:
Ventilation system; Yes, No, Size:
AC, Humidifier, De-humidifier:
Co2; Yes, No:
Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you
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Strain; Type : Cindy Limone photoperiod
Age from Sprout: December 1st about 85 days
Hydroponic, Change nutrient solution weekly
PH of water and runoff or solution in reservoir: Tap water 7.0 Solution 5.5 -6.0
What is strength of nutrient mix? EC, or TDS: EC 600-1000 ppm
Indoor or Outdoor: indoor
Light system, size and height from plants: 1000 watt led 13 inches from plant 1 and 278 watt LED 11 inches from plant 2
Temps; Day, Night: 85-65
Humidity; Day, Night: 20- 55
Ventilation system; Yes, No, Size: yes 6 inch intake, 6 inch exhaust 250 cfm blower with carbon filter
AC, Humidifier, De-humidifier: no
Co2; Yes, No: no
Kinda looks like some mixed signals there, hope you don’t mind a few extra questions.
Have you sprayed the plant with anything? Some of those spots look in line with damage from leaves being wet under lights.
Are you monitoring your res temps? If not, take a look at color of your roots and see if they’re bright white or maybe a little brownish.
What are you using for nutrients and what’s the mixing ratio?
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@dbrn32 I was sort of thinking the same thing. Did you recently prune your leaves back? I get edge burn when I prune my plants hard and they perspire. Bright lights are amplified by the moisture. Is not as blotchy as when ppl spray water which can also be microbes that have grown in the sprayer.
Your nutes are in the PPM range you want. Otherwise your plants look healthy (although that’s with the burple lighting).
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haven’t sprayed anything on them…res temps at 68 and roots look super healthy…using GH nutrients following the low end of their grow schedule. Could be ph fluctuation since I only have the chemical tester which is hard to gauge exact ph especially under burple lighting.
Thanks so much for the reply…this is my second grow (first photoperiod and first hydroponic grow) and I am pretty nervous about losing my plants.
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Possibly. Some people seem to do ok with them, others struggle. She could just be a little nute sensitive too. Maybe one of the hydro growers will have a little more feedback.
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Yes I recently pruned back the leaves since it was very thick and bushy. The other plant has been treated the same way and has no signs of problems. The only difference is the problem plant is right next to the fan and is under a higher powered light…wondering if that could come into play?
Thanks so much for your reply…I think(hope) you may have the diagnosis. Will try to get better pics after they wake up later today.
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Your plants at this point are pretty indestructible. I use GH Flora 3 part. You should be at 1 part Micro, 2parts bloom. In my DWC’s(5gal buckets) I start pushing the PPM’s to 1100. (`8mlM/16mlB/gallon). You should start at ~pH5.8. The nutes will hold the pH in an appropriate range during the next 7-14 days so don’t go crazy with pH adjustment. Just keep an eye on the leaf tips for burn. They will really be drinking water so keep the res topped up with water between changes to just below net pot. I change out every 7-14days just to keep things clean. I don’t really use much more than the GH Flora. Towards the end of flower you may start raising to 1M/3B (5/15ml) because the flowers really want the P,K. I do also use some armor Sl to stiffen the branches up a bit but it is not required.
I have flipped to watch. Keep posting as you go and feel free to ask questions.
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Also, you do not need to spray anything on the plant. Flower formation is better at lower humidities anyway. Plants naturally perspire to provide moisture to the leaves
I’m no expert, but looks like a potassium deficiency to me.
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Thanks Bogleg for the suggestion…looked it up and looks similar. Is there a test for Potassium deficiency?
here’s another pic under blurple…
Better pics later. Thanks so much for the help everyone!
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The leaf issues seem to be just a few and not widespread on all leaves. I still think it may be burn from the lights and moisture evap.
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That’s it right there. Get a better handle on your PH and you should see everything clear up. Your numbers in flower should be up around 1,200 ppm but of course the plant will dictate what it wants. I believe your PH was off and it unlocked a nutrient that crisped some leaves.
What is your reservoir size? You are changing solution weekly so I’m guessing it’s fairly small. As you progress in flower you will have to monitor and adjust more frequently with the smaller reservoir. This can cause PH issues very quickly.
Good call on this too: with low RH the vapor pressure deficit is pretty high which increases movement of nutrients.
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pH6 is not off for DWC. You have an effective range with a target of 5.8 starting.
ph and nitrient uptace cannabis - Search
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Another leaf reference, but often symptoms can overlap with different specific nutrients. GH Flora is broad spectrum and designed to be complete, but I do find it a bit weak in late flower for P, K.
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Thanks so much for the charts. got them saved on the computer for future reference.
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Your plants look healthy. The small botching should be ignored. Bring the lights down to 18 in to give a bit more intensity. Be patient. They will take time to fully mature. Keep pushing the GH Flora up to 1100-1200 ppm. Keeping them topped up with water between changes.
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