Problems With Soil PH in Organic Grow

Discussion in 'Organics' started by Majikoopa, Nov 29, 2017.


    Majikoopa Well-Known Member

    Hi all!

    For those of you who have seen my posts on here, this may be surprising but Im a little embarrassed to say I have been having some PH problems. Here's a rundown of what is going on:

    I use Fox Farm Original soil and, for years, it has been fine. My water in my area is good, but I run it through a carbon filter just to make sure it is fine. Typically it is about a 6.5 going in. I use all dry organic ferts and make sure to test for nutrient levels.

    Anyway, on some more sensitive plants (ducksfoot) I have been getting some terrible copper colored spots and necrosis of the leaf tissue. At first I treated with a little liquid bloom nutes as I hear Ducksfoot is greedy, again adjusted up to PH 6 or 6.5.

    Anyway, long story short the problem only got worse. After checking everything with a kit, I found N P and K were through the roof and soil PH was down in the 5s.... NO GOOD! Obviously we have some nute lock out due to the f'd up PH.

    I am starting a new grow and trying to make sure the water going in is more alkaline (7.5 or so), but lo and behold the runoff is testing in the 5.5 area or so. I have flushed with alkaline water a few times to no avail. I feel like I am going to keep running into problems if I keep using this soil, but didnt used to have this problem and certainly not with less sensitive strains.

    Three questions:

    1. Is it obvious I am doing something wrong?

    2. How would you adjust/address this problem? I am already watering with 7.5+ PH water, which just feels goofy.

    3. Is there a better brand of soil with less PH problems you'd recommend? I have to stay away from crab meal and oyster shells due to a severe crustacean allergy.

    Thanks all!

    Majikoopa Well-Known Member

    After some consideration, I am thinking I may throw a bit of garden lime in with it. What do you all think?
    MustangStudFarm likes this.

    Tyleb173rd Well-Known Member

    What dry organic amendments and how much did you use in the soil mix? Are you sure the NPK test is accurate? Pics of the plant?

    DonTesla Well-Known Member

    More pH controlling additives.
    More humus.

    Less Foxfarms, which is notorious for issues.
    More DIY, more control.

    Plus you can drop your ph on your water.. phosphorus will drop it, fungus will drop it, acids will drop it. you can also filter through a medium that is set to balance it ..

    and like T said, more pics!

    cheers man
    Tyleb173rd likes this.

    Wetdog Well-Known Member

    I think that simple act would have avoided all these problems in the first place.

    Top dressing some now will help, but adding it to the mix from the git go should be a regular practice.

    pHing water is mostly wasted effort in soil. It has, at best, a very temporary effect on the soils pH, while the soils pH has a huge effect on the water, soon bringing it to it's (the soils), pH. You noticed this when you pHed the runoff.

    Top dress the garden lime @ 2Tbl/gallon of mix in the container. When constructing a mix, add 1cup/cf of mix. I don't use OSF either, but have used Dolomite or Garden lime for decades. It is also the second ingredient in my mix, right after the peat moss.


    MustangStudFarm Well-Known Member

    Does this test chart look similar lol... I ended up diluting it with peatmoss. In my case, I might have been better using Pro-Mix because I was in a hurry and didn't have time for the dolomite to break down. Like WetDog said, Peat, dolomite, and aeration is pretty much what Pro-Mix is. It take dolomite 6mo to break down though. Calcium is what will bring your PH up...

    Wetdog Well-Known Member

    Stang ... calcium carbonate no matter the form (dolo, OSF, crab shell, etc), takes some time to break down, but that is different than having an EFFECT on pH. Depend on mesh size, it starts working on pH in ~2 weeks and having more of an effect as time goes on and it breaks down.

    It's not like nothing happens for 6 months. It's both a chemical and physical reaction that starts as soon as water is introduced. It's like, the full effects are reached in 6 months or so, but it starts working way before that.

    MustangStudFarm Well-Known Member

    I hope so. I diluted my soil with peat and perlite and it really killed my PH. I have oyster shell but I also need Mg, so I will get some dolomite.


    From what I have read about exchangeable hydrogen is that it makes the soil acidic and it's negative charge is easily replaced by the Ca with a + charge that bring up the PH. I think that I cut the soil with too much peat... The 2nd soil sample has more peat than the first. I was trying to get the K down to an acceptable level.

    MustangStudFarm Well-Known Member

    I was lost without getting my soil tested. I am only paying $25 for the tests at LoganLabs. I just got tired of guessing and I really wanted to figure out my problem.
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    Wetdog Well-Known Member

    Cool beans!

    $25 I can swing for a test, $50 is a bit rich, even with a bar graph. LOL

    Wanted to ask you though, have you ever thought of making your own ProMix? It's super simple (3 ingredients), and the only difficult part is locally sourcing 4cf bags of perlite. Here, they have gone up a bit to $18/4cf bag from $16. A bale of peat moss and pulverized dolomite lime are the other ingredients.

    Usually mix up a 32gal garbage can worth, dry, and then use as a base for soil mixes, worm bedding, whatever, adding whatever amendments for the intended task.

    ProMix is great stuff, just awful expensive for them to do the mixing.

    Just thought I'd ask.
    MustangStudFarm likes this.

    MustangStudFarm Well-Known Member

    ProMix is very expensive around where I live!!! This year, I was making leaf compost with grass clippings. I have ammended compost but I think that I will not amend the leaf mold with anything but Ca/Mg. I think that it will be very similar to ProMix when I am done. I already switched my worm bin to leaf mold, I still feel like I am experimenting though...

    MustangStudFarm Well-Known Member

    Oh man, I am being charged $30/3cuft of perlite... ProMix is around $70

    Wetdog Well-Known Member

    I hope you're at least getting a kiss to go along with that screwing.:roll::spew:The pro mix here is $38/bale and I thought THAT was outrageous.

    If there are any contractor/building supply places around, perlite is used as insulation for CBS walls and can usually be found there. Vermiculite is also, but you don't want that. I've gotten bags that were just labeled PERLITE on the front and the safety stuff and manuf on the back and that was it on the bag. It was identical to the Horticultural grade perlite that was still 1/2 full.

    Also, the feed store I go to used to order it for me with the weekly truck from the distributor. Never knew he could get it and he didn't have enough room to keep it in stock, plus being a slow seller. I only asked because he did keep big bags of vermiculite in stock for bedding. No idea what for, he never asked, but it was a steady seller. He now keeps a few bags in stock because after a few years of doing business he knows I'm good for ~4 bags/year.

    Anyway, it pays to ask around because it is bulky and a slow seller and floor space is valuable, but that doesn't mean it isn't available and at a reasonable price. I'm in a smallish town (~20,000), so you don't need a big city to find a local source.
    MustangStudFarm likes this.

    Banana444 Well-Known Member

    Oysters are not crustaceans, they are molluscs. So you have nothing to fear using oyster shells, which are great for regulating ph.
    Last edited: Dec 5, 2017

    Majikoopa Well-Known Member

    Not quite, it is a little more complicated than that, but I appreciate it man.
    Tyleb173rd likes this.

    Majikoopa Well-Known Member

    Ok so here is what was done based on the feedback I have received and some stuff read online. For the existing plants, some garden lime has been added as a top dressing, scratched in about an inch deep.

    Any unsprouted plants have been removed and the soil remixed with lime in the proportion of 2 tbsp/gallon with thw Fox Farms Original and replanted very carefully.

    For good measure, a couple more seeds were planted in Roots Organic planting mix with 2 TBSP/gal garden lime, 2 TBSP Happy Frog "Tomato and Vegetable" natural dry slow release ferts, and a little extra mycorrhiza for good measure was watered in.

    This way, they will be judged side by side to see if the problems are better/worse between the top dressed fox farms, the lime blended fox farms, and the Roots Organic with added lime.

    Attached is the pic of how the untreated Fox Farm plant that was flushed with Ph'd water looks, already having problems super early in the grow. This plant originally was just Fox Farms soil, nothing added. This pattern you see was a problem thrroughout the last grow too and was the first time in a while the original Fox Farms was used vs another spinoff of theirs.

    Any input based on the above info and pic?

    Attached Files:

  17. I know @Wetdog will agree but have you thought about making your own soil from scratch instead of buying a product that is unreliable at best. It is rather simple and the results will amaze you. Then you can control what and where you source everything. Just a thought. Good thought on the soil sample too. I hate when people throw amendments on the plant and hope something works.
    MustangStudFarm and Wetdog like this.

    Majikoopa Well-Known Member

    Thanks man. Yes I have been giving it some real thought as the off- the- shelf products have been inconsistent lately. Thanks on the testing stuff, I dont like just throwing nutes at something and hoping it works, agreed. Right now this grow is exclusively for seed/breeding (hoping to plant a new strain Im working on outdoors this spring), so I dont want to go whole hog investing to produce massive buds this time around, just want everything healthy if that makes sense. On my next grow for bud, however, I will definitely make my own soil based on the subcool recipe.

    Wetdog Well-Known Member

    The only thing that raised an eyebrow a bit was the tomato tone in the Roots. That can be bad news for freshly planted seeds. But, perhaps not. Time will tell on that one. Is Roots a hot mix? No experience with any bagged soil mixes.

    My absolute favorite for seeds, freshly rooted clones and for cloning itself is depleted, used soil. It's depleted, but not barren and has everything needed, just in minute amounts. Plus an established microherd.

    There will be a world of difference when you start making your own from scratch. Not only will you know exactly what's in there, but how much of each item was used and can adjust over time till you get the perfect mix for your style and growing environment.

    Figure on a couple of weeks at least before you see any sorts of results from the lime. Was it pulverized or prilled (pellets)? What was the brand and perhaps the label info? That would answer all my questions in one shot. LOL

    Majikoopa Well-Known Member

    Hi there thanks so much for the replies! Yes it is pelletized, organic garden lime.

    My understanding is that roots isn't a hot mix, rather it has some good stuff that will start to break down and feed the plants over time. Same with the dry nutes, my understanding is that it will take at least two or three weeks to start to break down- - either way it shouldnt be anything that will cause root burnage. Ingredients are pretty much things like feather meal, bone meal, fish meal, blood meal, bat guano etc, actually pretty similar to the subcool recipe lol.

    I have determined to make a small batch from scratch soon for sure!
    Wetdog likes this.

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