Yellow Spots - DWC

[rooms]

Problem: Yellow spots spreading on leaves, unhealthy new leaves

Medium/grow method: DWC

Feed and supplements used: GH 3-part, CAL-MAG, Armor Si, Recharge

water source: Well water (base PPM is 120)

Strain/age: Amnesia (harvested Aug 2017)

light used: 600W HPS

Climate: 70 to 78 (f), humidity 40 to 50%, res always below 70

Additional info: pH 5.8 - 6.1

It seems like a deficiency, but I'm not sure if it's due to overfeeding or underfeeding. The plants show signs of overfeeding (a few burnt tips, clawing, sketchy new leaves) but my PPM is only 300 on day 34 (down from 375 last week after a poor reaction by the plants). I am new and totally lost. Any help would be greatly appreciated. Thank you!!

 

[Rev. Green Genes]

Problem: Yellow spots spreading on leaves, unhealthy new leaves

Medium/grow method: DWC

Feed and supplements used: GH 3-part, CAL-MAG, Armor Si, Recharge

water source: Well water (base PPM is 120)

Strain/age: Amnesia (harvested Aug 2017)

light used: 600W HPS

Climate: 70 to 78 (f), humidity 40 to 50%, res always below 70

Additional info: pH 5.8 - 6.1

It seems like a deficiency, but I'm not sure if it's due to overfeeding or underfeeding. The plants show signs of overfeeding (a few burnt tips, clawing, sketchy new leaves) but my PPM is only 300 on day 34 (down from 375 last week after a poor reaction by the plants). I am new and totally lost. Any help would be greatly appreciated. Thank you!!

View attachment 866287

View attachment 866300

View attachment 866302

View attachment 866189

The good news for you is that they look very healthy. As you say there are claws, and the uppers look like they have a touch of heat stress from maybe light too close or not enough air flow. The lighter color and twistyness is not unusual in new leaves. The yellow spots are very small and insignificant, and some of them look like physical damage. Are you sure on the PPM reading? you should be able to go over 300 PPM at this stage without any problems.

 

[rooms]

Thank you for the insight, Reverend!

At this point, I'm not really sure of anything. I may have tried to push my PPM to 400 before they were ready, thus developing burnt tips. Then I probably confused light distance and/or heat issues with overfeeding, and that's how I ended up at 300 PPM on day 30. I promise not to ask a million questions, but how would you recommend increasing my PPM from here? Should I go to 350 for a day or two, then push to 400 and so on?

This is my first time growing autos. I tried really hard only to research info specific to autos and not photoperiod plants, but I failed to follow that rule with light distance. I couldn't get my T5 anywhere close to the distance most photoperiod peeps are doing. My 600W HPS is currently at 28" above the canopy and I'm still seeing cupping. So, light distance has probably been an issue all along. I'm also wondering if my two small fans aren't doing the job even though my closet temps are spot on.

Thanks again!

 

[Rev. Green Genes]

Hi @rooms you are so very close to having it just right. Some plants will always have variety or responses to conditions. A 600 watt HPS is strong light, and 30 inches is a good distance. I'm using the same light right now, and sometimes the cupping and 'crocodile teeth' happen anyway when they are young. When it gets into flower stretch she can handle it closer perhaps. Mine is only 12 inches or less right now, and they are handling it well, even though there is cupping.

As far as air flow goes, the plants are a touch close together, and the canopy is pretty thick. I would prune out the inner and lower leaves to increase air flow. Or you could also bend them apart and tie them to the wall.

For the PPM, if you mix up a gallon 400 PPM nutes, and add it to a gallon of 300 nutes, you should get 2 gallons at 350 PPM. See how the dilution works? When topping off a rez, that is where a lot of folks in hydro get pH spikes too. If it has been a while since the claws showed up and there are no new symptoms than you should be able to go to 400PPM, just add the base nutes for now, you probably already have enough amendments in there.

 

[Simplicio]

Thank you for the insight, Reverend!

At this point, I'm not really sure of anything. I may have tried to push my PPM to 400 before they were ready, thus developing burnt tips. Then I probably confused light distance and/or heat issues with overfeeding, and that's how I ended up at 300 PPM on day 30. I promise not to ask a million questions, but how would you recommend increasing my PPM from here? Should I go to 350 for a day or two, then push to 400 and so on?

This is my first time growing autos. I tried really hard only to research info specific to autos and not photoperiod plants, but I failed to follow that rule with light distance. I couldn't get my T5 anywhere close to the distance most photoperiod peeps are doing. My 600W HPS is currently at 28" above the canopy and I'm still seeing cupping. So, light distance has probably been an issue all along. I'm also wondering if my two small fans aren't doing the job even though my closet temps are spot on.

Thanks again!

Don't stress those plants by ramming too much food down their throats.
I'm at 250 ppm in dwc right now on week 6, and if anything they look over fed.
My last grow 350 ppm during late flower caused severe gold leaf problems and lower quality harvest.

These weeds will take the food they want even from very low ppm.

 

[rooms]

Hi @rooms you are so very close to having it just right. Some plants will always have variety or responses to conditions. A 600 watt HPS is strong light, and 30 inches is a good distance. I'm using the same light right now, and sometimes the cupping and 'crocodile teeth' happen anyway when they are young. When it gets into flower stretch she can handle it closer perhaps. Mine is only 12 inches or less right now, and they are handling it well, even though there is cupping.

As far as air flow goes, the plants are a touch close together, and the canopy is pretty thick. I would prune out the inner and lower leaves to increase air flow. Or you could also bend them apart and tie them to the wall.

For the PPM, if you mix up a gallon 400 PPM nutes, and add it to a gallon of 300 nutes, you should get 2 gallons at 350 PPM. See how the dilution works? When topping off a rez, that is where a lot of folks in hydro get pH spikes too. If it has been a while since the claws showed up and there are no new symptoms than you should be able to go to 400PPM, just add the base nutes for now, you probably already have enough amendments in there.

You've been most helpful, sir. Much obliged.

Don't stress those plants by ramming too much food down their throats.
I'm at 250 ppm in dwc right now on week 6, and if anything they look over fed.
My last grow 350 ppm during late flower caused severe gold leaf problems and lower quality harvest.

These weeds will take the food they want even from very low ppm.

Thanks for the reference, Simplicio! I would rather err on the side of caution than continue freaking out every time my plants show signs of overfeeding

 

[rooms]

For the record, I think my humidifier is causing burn spots on the outer leaves.

 

[Ydijadoit]

Have to agree with all the above input. I too, am running my first auto in hydro (waterfarm). I'm blown away by the light nute requirements so far. I am at 400ppm, with Flora and Calimagic, and she is happy, and drinking like a fish.
One thing I didn't see mentioned is what the PPM of your solution is doing between top ups? Should be falling, with a rise in PH. If it goes up as the plant consumes water, it's a bit too hot.
I was foolishly running my plant at 600ppm, last week. Slight tip burn, very dark green and waxy looking new growth, and rising PPM. Backed off to 400, and all is well.
Hope this helps, your grow looks very healthy to me!
Regards, Kyle

 

[rooms]

Hey Kyle, you bring up a good point! I raised my ppm to 350 on Monday. Since then, it will drop down to about 315 in one day, while the pH sits at a constant 5.7. I'm assuming this means I should raise the ppm, but I'm scared.