baxbax
Well-Known Member
Hi , I use 85 % phosphoric acid as ph down I feed plants with 5.5 and fix ph at 5.8 next day ph raise to + 6.5 . I'm searching for most stable ph down that can hold my ph for longest time possible in COCO -
Most stable pH down chemical ?
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Phosphoric acid works fine and is pretty standard.
When you say -'next day ph raise to 6.5' are you talking about the runoff from the pot?
When you say -'next day ph raise to 6.5' are you talking about the runoff from the pot?
Guy Cavallero
Well-Known Member
I'm with Weasel ......but the up/down action......whats that about? Some use lemon juice as a PH down too. I do find that the phosphoric acid has a shelf life. What used to take one drop to lower pH, after a year it may take four or five drops.
I find that it's normal for ph to rise in the rootzone. I grow in soilless mostly- peat moss and sometimes coco. I feed and water around 5.8. Runoff is 6.5 - 6.7. That's totally normal to me.
Guy Cavallero
Well-Known Member
Thats a good range. Even myself after a year get kind of confused about the media such as Pro mix. Considered soil or considered soil less? I have treated it like soil and PH always to 6.5, and I get 6.5 back out of my plant at runoff. I've never had a PH issue when in that range. Funny how the media plays such a key role in PH fluctuation.
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baxbax
Well-Known Member
yes , I fix runoff to 5.8 ( too much work and flush with 5.5 ph ) next day runoff is like 6.9
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- #7
baxbax
Well-Known Member
I have rust spotted leaves and don't know what is this .
I think it's probably fine. You can get pretty confused looking at the runoff. important to always make sure that you feed and water in the correct range. Runoff can be ignored for the most part.
How much calmag are you using?
Guy Cavallero
Well-Known Member
Not sure how in coco but it looks like calcium lockout due to overfeeding? Too much nitrogen....likely. What stage are your girls in?
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- #11
baxbax
Well-Known Member
I use 1.5 ml per 5 gallon , with other nutrients , recently I overdosed on calcium to fix this rust spots and I ran into iron def due to calcium toxicity now I use less cal mag .
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- #12
baxbax
Well-Known Member
I use low nitrogen nutrient , this is whole plant picture do you think I have N toxicity ? it's 25 days from seed
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- #13
baxbax
Well-Known Member
this is my last Iron deficiency because of using too much cal mag tried to fix this rust spots on lower leaves and iron def happen . I fixed it with flush and topped plant .
Guy Cavallero
Well-Known Member
No, I wouldn't say you have lockout judging by the state of your plant, I would say that you are just low on calcium. Use the Cal Mag according to its instructions and you won't overdo it. Did you say that these were autos? Do you use foliar? You can spray cacium nitrate on your plants in a spray bottle diluted down after lights out if you are only looking to increase your calcium levels and not overdo it on magnesium.
Hmmm... well, many deficiencies are so complex that very few experienced people are willing to make firm statements about the causes such as you are making. Though that doesn't mean you're not right.
Most would say to get your ph and feeding routine in line first and the rest will follow.
But in any case- 1.5 ml of calmag seems much to low to me and in coco would cause deficiencies. I use 4-5 ml of (botanicare) calmag per gallon.
Coco is a calmag hog and plants grown in it will show rust spots like that if you don't use enough.
How much calmag does it say to use- on the bottle ?
Most would say to get your ph and feeding routine in line first and the rest will follow.
But in any case- 1.5 ml of calmag seems much to low to me and in coco would cause deficiencies. I use 4-5 ml of (botanicare) calmag per gallon.
Coco is a calmag hog and plants grown in it will show rust spots like that if you don't use enough.
How much calmag does it say to use- on the bottle ?
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- #16
baxbax
Well-Known Member
it's photoperiod , can spray cal mag but what about flowering I can't spray cal mag on buds . can't rely on foliar spray
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- #17
baxbax
Well-Known Member
this is information about the calmag i use :
Organic Nitrogen (N) 3% of wich: Soluble organic Nitrogen (N) 2.8%. Calcium Oxide (CaO) 10% soluble in water. Magnesium Oxide (MgO) 2% soluble in water. Organic Carbon (C) 10%.
every application dosage on bottle is litre per hl .
I calculate amount I need to use by splitting according to botanicure cal mag 4 ml per gallon .
this is botanicure analysis :
Total Nitrogen (N) ….. 2.0%
1.94% Nitrate Nitrogen (N)
0.06% Water Soluble Nitrogen (N)
Calcium (Ca) ….. 3.2%
Magnesium (Mg) ….. 1.2%
1.2% Water Soluble Magnesium (Mg)
Iron (Fe) ….. 0.1%
0.1% Chelated Iron (Fe)
result is about 1 ml per gallon . trying use half strength ?
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- #18
baxbax
Well-Known Member
But I can't understand , how an imobile calcium can move from older ( my lower leaves ) and cause calcium def , if it's imobile it should happen to newer leaves like my iron deficiency , it's look like a mobile element moving from older leaves to new grow . Mobile nutrients are nitrogen in the form of nitrate, phosphorus (P) in the form of phosphate, potassium (K), magnesium (Mg), chlorine (Cl), zinc (Zn)
could this be Phosphorus deficiency due to my high ph ?
could this be Phosphorus deficiency due to my high ph ?
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- #19
baxbax
Well-Known Member
If this rust spots was identifiable I could fix it like my iron deficiency i fixed it with lowering ph and reducing cal mag
Well calcium isn't immobile. It's semi mobile and issues will show up on whichever leaves are (were) growing fastest. But I'm sure we can confuse ourselves for years to come trying to chase deficiencies. Iron deficiency is my favorite one because it's pretty obvious and actually fixable. The rest usually involve an overwhelming confusing combination of factors.
But I find that it generally always boils down to this-
Make sure your ph going in is around 5.6-5.8.
It sounds from your comments like you've been monkeying with the ph in the past. Try keeping it stable for a while.
Don't overfeed and don't underfeed. Underfeeding can cause deficiencies as well, obviously.
Make sure there's runoff at least some of the time.
If you really want to get to the bottom of it and you're growing several plants then it's worth doing a side by side with a couple of them- different amounts of calmag for the two plants.
But in my experience it's not that easy to give them too much calmag. Your more likely to Od them with all the nitrogen in it before causing other issues.
And the times I've grown in coco and tried skipping the calmag I got rust spots like that.or something like that. It was a long time ago.
But I find that it generally always boils down to this-
Make sure your ph going in is around 5.6-5.8.
It sounds from your comments like you've been monkeying with the ph in the past. Try keeping it stable for a while.
Don't overfeed and don't underfeed. Underfeeding can cause deficiencies as well, obviously.
Make sure there's runoff at least some of the time.
If you really want to get to the bottom of it and you're growing several plants then it's worth doing a side by side with a couple of them- different amounts of calmag for the two plants.
But in my experience it's not that easy to give them too much calmag. Your more likely to Od them with all the nitrogen in it before causing other issues.
And the times I've grown in coco and tried skipping the calmag I got rust spots like that.or something like that. It was a long time ago.
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