PH confusion: please help!

[Gorg]

I am so confused now. I have heard such contradicting information when it comes to correctly PHing coco and what is important to ph- the intake and/or runoff. I have a bio fertilizer topping in the substrate and I ph the intake with a light mixture of nutes at 6.2, and the runoff always jumps 7.0-7.2. I understand that the fertilizer and nutes will raise the ph once it goes through and that's why it jumps, but I have heard that the runoff ph doesn't matter, because apparently the ph of the incoming water is what is important for the roots to take it in.

However, if moisture in the substrate is a bit higher than 7, how are the roots not affected by this? I am getting bright yellowing of the leafs starting from the inside working its way outward to where it gets progressively greener, which I have heard that it can be from an iron deficiency and because iron uptake needs to be at slightly lower ph. However, I tried to balance things out by ph-ing my water to being more acidic, and even watering at 4.0, the runoff ph is still around 6.5. I'm worried that I might fry the plants if I lower the nute water even lower to counteract this. What would you recommend I do? I am getting a feeling that my ph is still way too high due to the bright yellowing of the leafs.

The plants are only 2 weeks old.

 

[Weaselcracker]

Ok so the advice below will be for regular coco with bottled nutes. Once you start mixing in powder/granulated nutes -I’m not sure. Maybe someone else has experience with that type of mix. Every time I’ve tried adding stuff to coco trying to turn it into something like a garden soil the plants have hated me.

But for regular coco-

Yes -generally don’t worry about the runoff ph unless there’s some very good reason to start looking at it. There generally isn’t.

Yes- PH will rise in the root zone and come out higher. That’s fine.

Always keep your ph between 5.6 and 5.8 for everything you put in.

 

[bluter]

1. pics help.

2. don't panic.

3. are there any problems with the plants ?

4. only worry about ph in

5. only worry about ph out if number 3 is a yes

6. there is a sweet spot for coco for ph in. i think it's about 5.8 which is the same as hempy. someone else may weigh in.

7. refer to number 2

8. good luck.

 

[Gorg]

Thank you for the quick replies so far! Here are some pics. I have 3 2-week old girls, only two have shown yellowing, meanwhile the other is considerably smaller than the 2, but shows no sign of yellow and the leafs seem a little more organized and more uniform, perhaps it's a different phenotype (I don't know, I'm brand new and this is my first grow). Jack Herer Autos.

The nutes I am using:

-Greenhouse Feeding Bio-Grow (powder topping)
-Greenhouse Feeding Bio-Bloom (powder topping)
-Canna A&B

I am cautious and still only using about 1/3 of what is suggested for all since they are still babies. I am using Canna Coco Plus with 30% perlite added in, 11 liter fabric pots. My tap water runs out of the faucet at 7.5-ish. I also just bought Calmag Plus and have been thinking that this might help, but have not used it yet. I water every other day.

 

[Weaselcracker]

With coco you definitely want to be adding CalMag every time or you will get deficiencies. I use it at around 3 to 4 ml per gallon. Keep in mind that it has a fair amount of nitrogen in it. So for my young seedlings I get by using only Cal mag for the first few weeks and don’t need any additional nutrients.

 

[bluter]

also new growth comes in a bit yellow and greens up as it gets older. if the center of the new leaves are yellow, and the tips greener, it's normal, you should be ok. if the tips are more yellow than the centers, then you may have an issue.

 

[Gorg]

Ok cool, all 3 had a tiny bit of yellowing when the first leafs were coming through, but they all seemed to recover except the problem plant. Like I said, I'm brand new to this and not 100% sure what looks normal or not. However, there seems to be a rip/tear/separation (?) that it did to itself now as you can see in the pics on the smaller yellow leaf on the right. Is this normal or am I missing something? Or is the leaf just bent up making way for the newer tiny ones? The other plants don't seem to have this.

Problem plant:

Plant #2:

Plant #3:

I started 3ml/gallon CalMag Plus tonight and measured the watering PH at 5.8 and will see if this helps..

 

[Weaselcracker]

The leaves are fine, a little variation is normal. The yellow isn’t normal but my best guess would be it is a deficiency from ph being too high, and therefore is treatable. At least it worked out that way for me in the past when I’ve had similar problems.

 

[Weaselcracker]

Also the Calmag, which is totally necessary in your case anyway, can help address this type of yellowing. The calmag ‘plus’ should have iron in it.