ph won't go down

Discussion in 'Sick Plants and Problems' started by Swa_Swa, Sep 4, 2007.

  1. I have 4 plants in the same soil and 2 of them are having ph problems. I'm using a phosphoric down to decrease my tap water which is about 7.2-7.4 down to about 6.5 but my ph stays 7.2 I have flushed more then 12 gallons through 3 gallon pots and no change on my blue labs truncheon and my chemical ph kit. Any thoughts?
  2. Whats your soil amended with, if anything?

    Sounds like 'something' is still changing your soil ph.
  3. its has hypnum, sand, and perlite. I used the same soil last grow with zero problems lol.
  4. I guess those 2 plants are going to die. I have no clue on what to do other then buying new soil but it doesn't make any sense!
  5. What's different this time swa? I mean that's usually the easiest way to figure out what's not wrong at least.

    All that water and soil is bad. Seems the wetter the more problems w/ph.

    You can level your ph w/lime, but do not over do it. Lime is 7, but caustic.

    Raise the temps to 85 and place wind blowing over soil to speed up drying. You have good drainage?

    Just ideas for ya swa. I only flush 2 weeks out, or if I think plant is dieing.
  6. The soil does drain adequately because of sand and perlite. The only difference that I can think of is last batch I started the seedlings in expert soil which was "hot" for fert then transplanted into this soil (3rd week into veg) and really didn't have any ph problems. This time I started them directly into the soil that I transplanted into that I used in first grow but it still doesn't make any sense to why I can put in 6-6.5 ph corrected water and come out with 7.2-7.3 run off every time. I let them completely dry out between flushing. I just started hitting them with some grow big fert every other watering so you would think the ph would drop but it didn't lol. That and its just 2 out of the 4 of the plants. The other 2 are taking off like rockets at about 4 weeks old.

    I do have good ventilation and temps are around 80-85 under 4 t5 fluros. I will have to try some lime or something because nitrogen is getting locked out severely...I have no new grow between the nodes.

    Also I'm foilar feeding which seems to be helping but there stunted. Thanks for the help.
  7. +rep swa swa for sharing and GL!

    Keep us informed?

  8. Lime is a big no no for you.
    Lime will raise pH and that's not what you are looking for.
    Acids are what you need.

    Did you also take pH runoff measurements from the 2 plants that are doing well?
    Or are you assuming they are not 7.2 because they grow so well?
    I've read different opinions on optimal pH for soil grows, anything from pH 6.3 to pH 6.8 is claimed to be best.

    I've seen plants looking pretty OK just above pH 5.0 which is 10 times more acidic then pH 6.0.
    So I think the flushing and drying out sequence may be worse of a problem then the pH 7.2 runoff itself.
    Your plant will have trouble taking up nutes from overwatered (=flushed soil) and the expansion/contraction cycle due to wet- and dryness will lower the soils ability to retain water and thus provide a stable water supply.

    Don't underestimate the complexity of soil chemistry and soil biology.
    It's not a 1+1=2 equation more like 1+X=Y when X and Y vary due to chemical and biological processes in the soil.
  9. I did a run off of all 4. The 2 that are doing good were at 6.8 I figured lime wouldn't work after reading up on it. I will water with 6.7-6.8 and keep hitting them with my fox farm grow big maybe that will keep it around 6.5 or lower like you said would probably still work.

    If I am putting in ph adjusted water and it still comes out higher, is that necessarily a bad thing? Maybe it was what you were saying and not actually because of the run off problem. They might be still up taking the water at what I'm putting it in as but for some reason the run off is just fuxored. I know that run off is a good indication of the actual soil ph...but just a thought.

    I'm probably just over thinking the whole situation and causing more problems by flushing but I had to start somewhere. My first grow I didn't even use a ph meter once lol.
  10. Lime is the last thing you want to add

    Hypnum is derived from hypnum mosses and have a higher and much broader pH range (5.0 to 7.5), and less persistent fibers than sphagnum peat.

    if the Hypnum in your soil is in the higher PH range it will continuously PH adjust the soil to its 7.5 as it breaks down

    despite the other 2 plants doing well this may infact be your issue
  11. Lime lowers ph too.

    You have no drainage because you flushed all the sand out. Now youre overwatered leading to messed up ph.

    keep watering that soil. I'll keep on letting mine dry out.

    my mix.

    8dry qts peat
    4 vermic
    4 perl
    4 gals 1/2 nutes
    36 oz pellitized lime.

    I grew in this before we even knew much about ph. just knew to keep it 6/7.

    It's old school and works. I water maybe Once in 1st 2weeks then as needed. budders get up to 2gals a day in last couple weeks. How you schedule that?
  12. I think I'm done with soil after this. I can't mix my own and I'm sick of growing in crap. Thanks for the help I now know the problem.

  13. if your soil ph was so high you needed to use lime, you need to throw the soil away and start over.:rolleyes:

    Swa_Swa google it anyway you want lime is used to raise the PH

    listen without defending
  14. start over? why would I lol I still have 3 that look amazing and some how are living in it. I plan on transplanting though.
  15. cant be rationalized that way Swa_Swa, even if they were all genetically identical (clones) one plant can easily have a less developed root system and more susceptable
    to issues, human error, and maybe the soil had a hot spot, to many variables to go there

    transplanting will solve it:D
  16. Swa, what was your conclusion on the problem?

    Yeah, and throw out your good plants and start over...j/k
  17. I would say a combination of the hypnum (or what ever else that could cause the soil to neutralize at 7.2-7.5 thus locking out nutes) and soil turning to mud. The 2 plants that are doing good do drain better. Although that doesn't necessarily mean it's the problem.

    As we speak I'm transplanting into some fox farm soil I was saving for the next grow (all 4 plants).

    I learned more this grow then my first lol.
  18. fox farm soil is a good choice , your plants will appreciate this :hello:
  19. swa swa do you play chess? There's a saying in chess that applies here.

    The only way to learn, is to lose some.

    Meaning if you don't deal w/these problems 1st hand you only have book knowledge. Books are good for info, but as w/me and gg no 2 books say the same thing. So what to do? Listen to gg or 420? neither! You take the info given and make your plan.

    swa learned too much water and soil? :)

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