@MidwestGuy @ogincognito
This is an OG Kush Auto from 420fastbuds, day 56 since sprouting, day 30 of flowering. Growing in 5 gallon fabric pot, coco/perlite. I’m using General Hydroponics Flora Trio + silica, Diamond Nectar, Calimagic, Raw yucca.
I just noticed some brown spotting on upper leaves. I’ve been giving CalMag with every fertigation. pH is always controlled, varying between 5.8-6.2.
I’ve had some problems with high EC runoff, probably because I’ve been trying to get by with one fertigation a day. Input EC is about 1200, and I’ve had to flush extensively to get the runoff EC with 300-400 points of the input. So this is one potential problem.
Also, the top of the plant is quite close to the light, about 8-10 inches.], so light burn is a possibility.
Any thoughts?
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When you’re feeding the coco are you getting liberal run off?? My normal input EC is 1.6-1.8. Under intense lighting the plant’s calcium needs can increase as well, what’s the current PPFD of the lighting, I would tie those taller branches off to the side, anything to get those more distance from the light. You may want to consider super cropping those tops 
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Yes. Getting lots of runoff, but I have to give >4 liters each time, as it’s getting pretty dry between fertigating - I may switch to 2x day.
Not sure about the PPFD. The light is set at 100% and AC Infinity says to leave 18” spacing , buts it’s like 4” for the main cola and 10” for the surrounding buds.
If I super top the main cola at this stage, will those buds still develop properly?
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Are you feeding daily or at a minimum keeping the coco damp? Coco should never go dry
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I super crop in early flower after the stretch often to create an even canopy so all the bud sites are receiving equal lighting
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Thanks for the tag. I don’t have anything to offer beyond what @OGIncognito has said.
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I’m curious what your tent temps and humidity are running? That seems like a lot of water/feed. I’m not far behind you and I’m running 12 cups (2.8 liters) with plenty of runoff.
When you flush, Is it with PH’d water? If my runoff gets out of whack, I flush with the same nutrient solution I’m feeding with, and I do it back to back with feeding. Giving about 15 minutes to half an hour in between. I think just as important, maybe even moreso, is that I see my PH raising back in place. I’m guessing with your EC climbing, your PH is falling.
OGIncognito- the top of the coco gets quite dry, not sure if it’s dry all the way down, don’t think so because she’s been very healthy until now. I’ll increase the fertigating to twice a day.
If I supercrop, do I need to support the part above the super crop, like at a 90° angle?
Old nail pounder: temp 72-75, RH 50-55, typically. I’ve never flushed, just fertigate once a day (until now). And while I checked the EC of the runoff, I’ve never checked the pH, because in the past, it’s never deviated from the input I’ll check oh next time.
I’ve been following a feeding schedule from Cocoforcannabis:
It is similar to one from Growweedeasy.
Neither of them goes above ~ EC1300 (1.3). But 420fastbuds, where I got the seeds, says that the 2 strains I’m growing (OG Kush Auto and Northern Loghts Auto) like a high level of nutes.
Do you think I should aim for higher EC than the charts recommends?
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I tried bending over the three tallest colas, using plastic LST clips to hold them in place. I guess this is similar to supercropping. I also raised the light a few inches.
So the crown is now 12" from the light, instead of 4".
before:
After:
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That 1.3 is low Growmie, 1.6 to even 2.0 is the norm for growing in coco.
@OGIncognito
I’m continuing to see lots of new brown spotting on the upper leaves, but not much lower down:
Upper:
Lower:
I’m at day 71 since popping, day 44 of flowering.
I’m managing the EC, input 1200-1300 us/cm, and I fertigate until runoff is less than ~1600 - some days a but higher, some lower.
Input pH is in correct range - I don’t measure the runoff pH.
The tent is at about 72F and about 40-45% RH
I super-cropped the highest 4 colas a few weeks ago (because of the same spotting issue), and they are now growing back towards the light, but not as close as before, maybe 10-12"
I turned down the light from 100% to 90%.
Is this a serious problem or can I ignore it?
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Is that EC you posted actually 1.2 and 1.3?? If so that’s low for my feeding routine at 1.8. Looks like a classic calcium deficiency Growmie. A Phosphorus deficiency is typically accompanied by a calcium deficiency but I’m not seeing that.
This is critical, input and medium PH can be different and the medium PH needs to be in range for nutrient absorption by the roots
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@OGIncognito , @MidwestGuy
Remember that I am using coco-coir, not soil. The input pH has been between 5.8 and 6.3 - I try to vary it on different days.
I just did a test, fertigating with 1.5 liters of nutes at EC 1400, pH 6.2.
The first runoff was pH 5.7. Then I gave another 500 ml, and the runoff pH was 5.4
If a runoff pH 5.4-5.7 is too low, how do I correct that? Raise the pH of the input?
Should I add add extra CalMag to the medium?
Would flushing with FloraKleen help?
@OGIncognito
Regarding the input EC, I tried raising it, like you suggested, in 100 us/cm Increments, and got up to 1400.
But then I started having problems with very high runoff, over 2000, requiring extensive flushes with more nutes at every fertigation
So I cut the input back to ~1200 (the level recommended in the nutrient schedule I’ m following, which is pasted above in this thread.)
I should also add that I’ve been trying to fertigate twice a day, but now and then I don’t have time to do the evening feed, and the coco looks pretty dry the next morning. Could that be contributing to the problem?
This is either PPMs or an EC of 1.4 and run off PH is still critical regardless of the medium. This doesn’t apply to organic growing for the PH
“This is either PPMs or an EC of 1.4 and run off PH is still critical regardless of the medium. This doesn’t apply to organic growing for the PH”
You are expressing EC in milli siemens/cm (e.g. 1.4), and I am doing it in micro siemens/cm (e.g.1400). Same measurement, just different scales. PPM 500 is 1/2 of ms/cm.
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Agree, still too low for plants in this growth stage 1.8-2.0 is where a plant in flower should be getting fed. What organic nutrients are you using in coco. Coco is not a good medium for organic style of growing
