Why does ph rise in veg and drop in bloom?

MichiganMedGrower

MichiganMedGrower

Well-Known Member
Rising is from fresh buffers (calcium) if in soil or simply the plants feeding.

Lowering is from Overfeeding, overwatering, over use of ph down, not enough buffers (calcium) in the medium or they have been used up washed out.

It is normal for ph to rise and fall as plants go through processes. Over time one way or the other only shows a problem exists.
 
Rakin

Rakin

Well-Known Member
Michael Huntherz said:
Yeah, P boosters are bullshit.
Any P ratio higher than 1-3-2 is magical thinking garbage.
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I like things simple. More is less kind of guy. With all the different nutes and additives out there it can get pretty overwhelming and expensive. Hell with all that.
 
Rakin

Rakin

Well-Known Member
Johnny Lawrence said:
Only in bloom?

Context matters. Reread what the op is asking.
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Dude. Things are real fresh befor bloom. Add the fact that flower chambers usually have more light and more heat. If you are going to get bacteria and such ther is a bigger chance in flower. I’ve had that issue and it was from the diffusers. Bacteria wouldn’t get way of wack until flower and then the ph would drop so don’t. Sorry you are to narrow minded to think of that.
 
Johnny Lawrence

Johnny Lawrence

Well-Known Member
Rakin said:
Dude. Things are real fresh befor bloom. Add the fact that flower chambers usually have more light and more heat. If you are going to get bacteria and such ther is a bigger chance in flower. I’ve had that issue and it was from the diffusers. Bacteria wouldn’t get way of wack until flower and then the ph would drop so don’t. Sorry you are to narrow minded to think of that.
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Well then that must be exactly what the OP is experiencing. It seems that you've solved the case.

Nice work, Columbo.
 
Rahz

Rahz

Well-Known Member
High nitrate nitrogen fertilizer and consequential high nitrate uptake increases PH. Transitioning to flower, P content is increased and N content is decreased (at least as a percentage). Consequential high P uptake decreases PH.

In flower PH can tend to dip but in my experience less so than the up swings in veg. P content of many bloom ferts may be higher than necessary. A healthy plant in veg FALLING/FALLING/RISING and in flower FALLING/FALLING/STATIC.
 
C

churchhaze

Well-Known Member
H2PO4- uptake and NO3- uptake actually both raise pH. as they're both replaced with OH-. (otherwise the solution would be left with a charge)

K+ and Ca++ are replaced with H+ and thus lower pH when they're taken up.

There is no hard rule of thumb saying pH goes up in veg and down in flowering or the other way around. That would have more to do with your nutrient levels which indirectly could imply an unnoticeable deficiency. (where growth would speed up if fixed). If pH is rising, it's likely the plant isn't taking K+ and/or Ca++ as fast as it could be. Getting a small amount of N as NH4+ would also help with pH rising problems.
 
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MichiganMedGrower

MichiganMedGrower

Well-Known Member
churchhaze said:
H2PO4- uptake and NO3- uptake actually both raise pH. as they're both replaced with OH-. (otherwise the solution would be left with a charge)

K+ and Ca++ are replaced with H+ and thus lower pH when they're taken up.

There is no hard rule of thumb saying pH goes up in veg and down in flowering or the other way around. That would have more to do with your nutrient levels which indirectly could imply an unnoticeable deficiency. (where growth would speed up if fixed). If pH is rising, it's likely the plant isn't taking K+ and/or Ca++ as fast as it could be. Getting a small amount of N as NH4+ would also help with pH rising problems.
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Many times this mid flower P and Ca uptake issue can be fixed by using a balanced complete Grow ratio fertilizer with micronutrients.

I have dropped pk heavy fertilizer all together at this point.

In potting soil in my case.
 
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