Soil pH issue

ItBurns420

Active Member
Hello all! Long time lurker, first time poster. Let's get to it.

I have been growing for a few years now but always hydro (hand watered in coco.) I decided to switch to organic for this grow and so far I've had nothing but headaches when I thought I was going to be making things easier on myself lol. I purchased a super soil mix from a guy locally and it came very highly recommended. It's equal parts sphagnum, compost, and perlite plus whatever he amends with and it also has bio char in it. Everything I've ever read about organic soils has taught me that the mix needs to be composted before use, however the guy making it advised that with his blend that is not necessary. His instructions were to simply plant and water it in with compost tea. I got to see the inside of his greenhouse when I was there and it was filled with lush green plants so against my better judgement I followed his instructions. Now I am 2 weeks into flower and I'm having issues. Several of my plants are very light green which led me to believe they were N deficient so I top dressed with some high N guano and begin watering with tea every other watering. I saw some recovery initially but the plants were not fully recovering and I started to see some necrotic spots in the margins of the leaves. I did a slurry test and determined that my ph in the root zone is 7.4. Eureka! Well now I'm trying to find information on how to lower the pH of my soil and I'm not having any luck. One thing I read conflicts the other and now I'm very confused about how to move forward. Any word of wisdom from the organic gurus here? Thanks a ton for any advice you can provide!
 

ShLUbY

Well-Known Member
are you letting the medium dry out too much? when peat gets dried out it can become very hydrophobic. then it becomes hard to get your pot of soil re-moistened. one thing you have to remember, for CEC to take place in these soils there has to be water present to put things into solution. So any shortage in moisture can, over time, lead to a shortage in nutrients available.

where is your yellowing taking place? if it's the lower leaves, you have a nitrogen def most likely. it's hard to diagnose plant problems without pictures!
 

ItBurns420

Active Member
I am watering every other day so I don't think my soil is drying out. I've been very careful not to let it get too dry. The yellowing is happening pretty much over the entire plant. I'll try to get a few pictures in a little while.
 

ShLUbY

Well-Known Member
I am watering every other day so I don't think my soil is drying out. I've been very careful not to let it get too dry. The yellowing is happening pretty much over the entire plant. I'll try to get a few pictures in a little while.
pictures would go a long way :)
 

NaturalFarmer

Well-Known Member
Chances are you need to raise the pH and get calcium up because peat is acidic and it is doubtful compost raised it enough. Get some lime or wood ash (raise pH) and gypsum (cal) and top dress. Hard to know for sure without knowing his recipe but IMO that is the safe bet.
 

NaturalFarmer

Well-Known Member
Yeah I would say so. Sounds like a fucked up soil mix. What does the soil look like? loose or compacted? 7.4 would be hard to get with peat unless you have way to much dolomite or carbonate(reread probably biochar too). Top dress with straight peat that will bring it down. gypsum still wont hurt and may even out the mag if he used too much dolomite.
 
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ItBurns420

Active Member
Hey brother no worries! I'm just glad to be getting some responses lol. I tried reddit first but I'm quickly learning that there is not a lot of help to be found there. I'm on a well that I'm filtering through an ro unit. It's pH varies from day to day and is generally in the 6.8 - 7.2 range. I snapped some pics of one the worst plants. I don't have any natural light available in my space so I put it under a t5 for the pictures. The color seems to be pretty true to what I am seeing.

. https://imgur.com/gallery/YqREX
 

NaturalFarmer

Well-Known Member
You should get some fish hydrolysate and kelp IMO. Plant looks nice but hungry. Could be iron but probably just ran out of juice in the soil and needs N. Plants also look a little hot, what temps do have?

pH looks good to me though, I didnt see any signs
 

ItBurns420

Active Member
I actually have both of those on hand already. I use them in my tea. I agree totally that it looks nice that's why it's driving me crazy that I can't get it fed enough. I've top dressed with guano a couple of times trying to get them to darken up but they just don't seem to be responding. Although it does appear that the be growth is just slightly darker green. I'm so used to seeing immediate results with hydro maybe I'm just being impatient lol. Since I'm using fish hydro and kelp in my tea should I still use more?
 

NaturalFarmer

Well-Known Member
I would get a 1/2 cup of gypsum on as a topdress and mix it into the soil a bit.
4 tbs of fish/ gallon and drench the soil.
Use the Kelp as a foliar.

If that doesn't bring it back green in a couple days you may have to get a little blood meal or some other iron source. Neither kelp or fish will give you iron. Have any rusty nails?
 

ItBurns420

Active Member
Should I be using anything foliar since there are already buds forming? Also, with week three of bloom starting in a couple of days should I be putting that much N into the pot or would it be better to find a different source of iron?
 

NaturalFarmer

Well-Known Member
Try to check your pH again if you can but you can bring her back to shape. I suspect that the pH reading you have was slightly off but still high and throwing off your iron uptake(if the fish doesnt work). Bring it down with some peat/1/2cup gypsum topdress and I think it will go away.

I foliar with WSC(calcium) for a week at flip and then kelp/fulvic/epsom salt for about three or four weeks and then just water.
 
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greasemonkeymann

Well-Known Member
I am watering every other day so I don't think my soil is drying out. I've been very careful not to let it get too dry. The yellowing is happening pretty much over the entire plant. I'll try to get a few pictures in a little while.
what size is the container?
you can't see it, the plant is markedly larger than the container, organics need room to grow, much more so than chelated grows.
those plants look alright, if anything you need a soluble form of nitrogen rather than a topdress
ignore the ph, taking ph from an amended soil is a fools errand at best, not to mention that's well within the allowances, that plant would not grow nearly that big if the root exudates didn't have the ph in check.
if it's in a plastic container put that container in another, half-filled with soil and that'll work as sort of a transplant, that far into flower you don't want to do a traditional transplant, or it'll slow it down too much during flower.
but for that size of plant, i'd go with no less than 8 gallons at least
 

greasemonkeymann

Well-Known Member
Should I be using anything foliar since there are already buds forming? Also, with week three of bloom starting in a couple of days should I be putting that much N into the pot or would it be better to find a different source of iron?
if you have no issues with using organic inputs, i'd simply use urine
the absolute quickest way to give them nitrogen
looks like a normal rootbound/nitrogen hungry plant to me
do NOT add any more topdress...
 

ShLUbY

Well-Known Member
I think your plants look pretty good aside from the slight discoloration.

this is not a N deficiency. you can clearly see that the lower portion of your plant is very green, while the upper portion remains the lighter color. If your plant were N deficient, it would start pulling nitrogen from the lower leaves before yellowing the newer growth. Nitrogen is a mobile element in the plant.

So this leaves two options....

1. your container is too small and rootbound and there is not much left for the microbes to consume and feed your plant... or they just simply can't keep up anymore. how big is the container? as mentioned above, i like a minimum of 1 gal into 7 gal for flower, and i'm probably going to start doing 1 gal into 10 gals so they can settle in for 3 weeks before flowering.

2. you have the ph issue that you are concerned about, and need to get something to bring down the ph of your soil (i like the peat that was mentioned above). i'm sure there are other options available but i would only make this adjustment if your container isn't too small/rootbound.
 

ItBurns420

Active Member
Right now I'm using 5 gallon smart parts. As far as I can tell they aren't root bound yet. After speaking to a couple of friends who are using the same soil and also having similar issues I believe the problem may be that the guy is using biochar that is not preactivated. From what I've been reading today if you do not inoculate your char it can actual steal nutrients from the soil making it inaccessible to the plant. I really want to start doing notill and I was already thinking of bumping up the pot size to 10g to facilitate this. I'm quite disappointed in this guy's soil blend. Unfortunately I already purchased enough to fill another set of pots so I'm going to have to make due with what I have on hand for now. I'll definitely be trying my hand at making my own mix. Was thinking of trying out the recipe that's on the first page of the rols mega thread. I have a batch of tea ready that I'll be watering with tonight and this morning I made a hydrated kelp meal paste that I'll be using as a foliar tonight and the next time I water I'll be hitting them with some fish hydro. I really appreciate all of the advice you guys have provided so far and if you're interested I'll check back in to keep you updated on my progress.
 

ShLUbY

Well-Known Member
one thing you need to remember with the smart pots.... 5 gals is really not a lot. Remember that they are designed to dry out around the edges, which can actually equate to quite a bit of less active dryer soil. So you're losing a portion of that 5 gal, plus if they are not filled to the absolute brim AND mulched so no light can get to the roots and they grow all the way to the surface, you're losing another portion of your 5 gal up there.

these factors are why i believe most people in living soil are preferring to run bigger containers. just a thought i had
 
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