Tops going yellow under cob

Hi all!

Please can someone help me with how much food I should be feeding my babies.


I have been feeding her 1.2 for the past week but I noticed some black spots and lighter colors and increased to 1.4-1.6. Ph6.

Using Cxb3590.


I simply add more calmag to fix?

Thanks!

Medium?fert & additives used?cob distance?which Ph meter ? Tap /filtered/ RO water? Measuring inaccurate runoff? Check for pests/fungal first?

Those photos: its hard to get an idea of the tips, some look burnt some not.

All of them look like they have powdery mildew.

I'm sorry I wasent more detailed.

Yes they all have pm. My dehumidifier died out and was running at high humidity for a while and it spread. I don't find pm to be a big problem though. I spray it once a day to wash it off.


My medium is perlite.

Ferts are a mix of calmag (0.4) and a and b veg feed(0.. To give them a total of 1.2ec


Tap water 0.2.

Cobs are 9ft away avg par is 700 lights on 24/7.

They were doing really well the other day but now they seem like the leds have used up all their nutrients

Looks like a calcium deficiency. What stage are they? How many weeks into veg or flower?
Are you really running your cobs 9ft away from the canopy? I normally have my cobs just over 1ft away. What wattage are you pushing out of each cob?

First of all, if your inhaling pure flower, then take care of that PM asap.......blasting the end product through butane, co2,ethanol= solvents, rosin press, edibles/canna butter(decarbing it),whatever, is a different matter for personal use.

9ft sounds like a typo? If you're really in hempy(perlite) and flushing salts occasionally with your low tds tap? Then I would say deficient(no tox/ph lock); up the feed & Cal/mag & see if they improve...hydro is not my game though. Hopefully some experts chime in.

Good luck

you're at 800 ppm? that's your problem. Get that up to 1000-1200. and raise your ph, or check your run off, im guessing you are running off way to low if you are going in at 6. the run off should be 6.

kushedy said:

Looks like a calcium deficiency. What stage are they? How many weeks into veg or flower?
Are you really running your cobs 9ft away from the canopy? I normally have my cobs just over 1ft away. What wattage are you pushing out of each cob?

Click to expand...

They in VEG.

Yes im running my cobs 9ft (nine feet) away. @90w Cxb3590 DD

PH is 6.

I have increased my EC to 1.6 and the plants seem happier, but I am still getting slight ca deficiencies. Maybe I will increase to 1.8 soon.

Right now im not running co2, 300PPM co2. I will add for flower.

Umols at the canopy is around 800. 24/h light.

RH 60 - 65.77-82F

PSUAGRO. said:

First of all, if your inhaling pure flower, then take care of that PM asap.......blasting the end product through butane, co2,ethanol= solvents, rosin press, edibles/canna butter(decarbing it),whatever, is a different matter for personal use.

9ft sounds like a typo? If you're really in hempy(perlite) and flushing salts occasionally with your low tds tap? Then I would say deficient(no tox/ph lock); up the feed & Cal/mag & see if they improve...hydro is not my game though. Hopefully some experts chime in.

Good luck

Click to expand...

I did exactly that. I think they need a bit more. They are growing like fire.

I can't get rid of the pm once a leaf is infected. Only new growth is fine. Should I cut away all the leaves? I would prefer to save the leaves. Pm doesent seem to cause any problems. I make Rosin from the flower.


I'm hand watering dtw using perlite. Not hempy.

See pic below they seem OK for now

Porky101 said:

I'm sorry I wasent more detailed.

Yes they all have pm. My dehumidifier died out and was running at high humidity for a while and it spread. I don't find pm to be a big problem though. I spray it once a day to wash it off.


My medium is perlite.

Ferts are a mix of calmag (0.4) and a and b veg feed(0.. To give them a total of 1.2ec


Tap water 0.2.

Cobs are 9ft away avg par is 700 lights on 24/7.

They were doing really well the other day but now they seem like the leds have used up all their nutrients

Click to expand...

700 par 24 hours? Thats a lot of light. You can flower perfectly with half of that (12 hours). Up feed and lower DLI is mybbest guess.

Rocket Soul said:

700 par 24 hours? Thats a lot of light. You can flower perfectly with half of that (12 hours). Up feed and lower DLI is mybbest guess.

Click to expand...

Thanks for your help.

I will do that.

I have put my plants into flower now. They are getting about 800Umols under COB LED lights. 600PPM co2 1.8EC

Porky101 said:

I'm sorry I wasent more detailed.

Yes they all have pm. My dehumidifier died out and was running at high humidity for a while and it spread. I don't find pm to be a big problem though. I spray it once a day to wash it off.


My medium is perlite.

Ferts are a mix of calmag (0.4) and a and b veg feed(0.. To give them a total of 1.2ec


Tap water 0.2.

Cobs are 9ft away avg par is 700 lights on 24/7.

They were doing really well the other day but now they seem like the leds have used up all their nutrients

Click to expand...

You need to give your plants some rest their stressed out pm can be handled with some green clean and some good air movement

I have almost never killed a plant but in veg with PM I would kill then and start over.

How do you have 700 par at 9 ft away @80w a cob?

DaFreak said:

I have almost never killed a plant but in veg with PM I would kill then and start over.

Click to expand...

Cut off most of the leaves. Plant seems fine. PM is a constant battle for me. Doesent seem to be a problem aslong as I spray them daily to wash it off.

PrometheanLeaf said:

How do you have 700 par at 9 ft away @80w a cob?

Click to expand...

Lots of them.



I have put my plants into flower now. I am still feeding them VEG nutes @ 1,8EC

Here are my nutes, I make my own:


N 111PPM
K 105PPM
P 46PPM
MG 54PPM
CA 136PPM
S 73PPM
FE 2.5PPM
ZN 1.2
B 0.4
Cu 0.6
Mo 0.06
Na 0.54
Mn 1.5




When should I switch over to bloom nutes? I am in day 3 flower.


My bloom nutes are the same as my VEG nutes but the NPK is different.

Bloom NPKCAMG:

N115
K170
P67
MG50
CA120

Porky101 said:

I'm sorry I wasent more detailed.

Yes they all have pm. My dehumidifier died out and was running at high humidity for a while and it spread. I don't find pm to be a big problem though. I spray it once a day to wash it off.


My medium is perlite.

Ferts are a mix of calmag (0.4) and a and b veg feed(0.. To give them a total of 1.2ec


Tap water 0.2.

Cobs are 9ft away avg par is 700 lights on 24/7.

They were doing really well the other day but now they seem like the leds have used up all their nutrients

Click to expand...

Hemp bucket?

Obepawn said:

Hemp bucket?

Click to expand...

NO, DTW

500-800umols

1000PPM co2 injection

How they looking? Day 2 flower.