Very Yellow New Growth

[TrueGreen420]

I am having problems with one of my plants. Can someone please give some advice.
Problem: Yellow New Growth

Medium/grow method: Botanicare Cocogro

Feed: and supplements used: Advanced Nutrients PH Perfect Micro, Grow, Bloom and CalMag

water source: RO Water

Strain/age: Nirvana Ice 3rd week of Flower

light used: 675 Watt Vipar LED COB

Climate: 72 LIGHTS OUT/ 75 LIGHTS ON

Additional info: PH 5.8

 

[Dainn]

Ironically it looks like Iron deficiency possible zinc as well from pictures, @Waira will be able to help you out better than I. May help to upload a picture in natural light.

 

[Heavily Medicated]

I think you may be frying them with the light. Raise the light some and see if that helps.

 

[Waira]

..classic Fe defc.,.. notice how it's yellowing from the "palms" out to the tips,... you need to check the in-pot pH and see if it's about 6.8 or higher, where a few micronutrient elements tend to lock out fast,... it's that, or a simple lack-of, which needs to be fixed by treating with a dedicated micronutrient supplement,.. Earth Juice Microblast is a good one,... foliar application will be best and fastest but you'll need a wetting agent to treat effectively,..spray tops and bottoms of leaves,... the wetting agent takes the surface tension out of the solution so it coats and sticks better, instead of just beading up,... more surface area covered = more absorbed... Maximum ass-kick is with Optic Foliar's Transport conc., mixed with the micronute supp',... this product allows temporary penetration right through the leaf cuticle and directly into leaf tissues,. no wetting agent needed!.. Immmobile nute defc.'s can be a bitch to correct-- slow response, repeated treatments needed,....

 

[TrueGreen420]

Thank you for the help Waira

 

[TrueGreen420]

Waira what is the best way to check the PH in the pot? I checked the runoff and it is 5.7

 

[Waira]

well, that itself is lousy for accuracy, not a reliable measurement of the actual in-pot pH,...but in any case, the fact that it's pretty acidic at least tells us that the in-pot pH is not alkaline,... how much Ca-Mg? With RO water use, this is a good thing, and in coco, necessary unless the nutes are coco-specialized... The best tool for the $ is the Accurate 8 soil pH probe for direct in-pot measurements (fine for coco too),... not very expensive, worth it's weight in gold sometimes! 5.7 is a little low even for coco,...
...we do have an improved method and calculation for run-off testing of pH, but it's still an iffy estimate,.. it's in the highlighted section above this one,... BUT since you're in coco, this isn't recommended because it may screw up the CEC of the coco,... it's part of the reason why you shouldn't use plain water alone in coco, include Ca-Mg at least,....

 

[TrueGreen420]

well, that itself is lousy for accuracy, not a reliable measurement of the actual in-pot pH,...but in any case, the fact that it's pretty acidic at least tells us that the in-pot pH is not alkaline,... how much Ca-Mg? With RO water use, this is a good thing, and in coco, necessary unless the nutes are coco-specialized... The best tool for the $ is the Accurate 8 soil pH probe for direct in-pot measurements (fine for coco too),... not very expensive, worth it's weight in gold sometimes! 5.7 is a little low even for coco,...
...we do have an improved method and calculation for run-off testing of pH, but it's still an iffy estimate,.. it's in the highlighted section above this one,... BUT since you're in coco, this isn't recommended because it may screw up the CEC of the coco,... it's part of the reason why you shouldn't use plain water alone in coco, include Ca-Mg at least,....

I always use 1 tablespoon of Cal-Mag per gallon of water. I will order the Accurate 8 soil probe. Thanks for the help.

 

[TrueGreen420]

well, that itself is lousy for accuracy, not a reliable measurement of the actual in-pot pH,...but in any case, the fact that it's pretty acidic at least tells us that the in-pot pH is not alkaline,... how much Ca-Mg? With RO water use, this is a good thing, and in coco, necessary unless the nutes are coco-specialized... The best tool for the $ is the Accurate 8 soil pH probe for direct in-pot measurements (fine for coco too),... not very expensive, worth it's weight in gold sometimes! 5.7 is a little low even for coco,...
...we do have an improved method and calculation for run-off testing of pH, but it's still an iffy estimate,.. it's in the highlighted section above this one,... BUT since you're in coco, this isn't recommended because it may screw up the CEC of the coco,... it's part of the reason why you shouldn't use plain water alone in coco, include Ca-Mg at least,....

Correction I use 1 teaspoon per every gallon of RO water.

 

[Waira]

... better!.... as for the Fe defc., acidic conditions don't lock it out, so you likely have a basic lack-of going on here,... I recommend a dedicated micronutrient supplement; Earth Juice Microblast is a fine choice,... I'd treat both soil and do foliar, but you'll need a wetting agent to do foliar effectively... it allows the spray to coat and stick better, rather than bead up,... spray tops and bottoms of leaves, keep out of direct light until dry,.. I like the hit it again with plain water lightly, to redissolve the goodies and get more in,...