Soil tests are back, and Houston we have a problem.

SNEAKYp

SNEAKYp

Well-Known Member
First off thanks for the input! This soil is a mix of municipal certified OMRI compost and leaf mold with crushed lava rocks as a drainage component.

Update:
I had the soil tested a couple weeks after the first post and the PH for two samples was 7.9 and 7.8, YIKES.

I recently got the soil tested and I’ve successfully lowered the PH down to 7.0 after three months of the soil cooking with a mixture of elemental sulfur and aluminum sulfide (I know not organic). The soil being so high in PH I felt I had little choice, but to go a hybrid between a longer reaction with the elemental sulfur and a chemical reaction with the sulfide.

These tests were done at the agricultural extension of my state so I have high confidence in their accuracy.

Here’s where we stand today:
PH-7.0
P: 67
K: 587
Mn: 240
Zn: 307
Cu: 84
S: 7478
CEC: 35.2 meq/ 100 cc
 
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waktoo

Well-Known Member
SNEAKYp said:
Waktoo, the PH of the tap water around here is ~8.4. I use mostly rainwater though.
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What's that mean?

What water was used to mix the soil?

What water was used to keep it moist while it cycled?

Have you grown anything in these soils?

Have you tested the rain water, for pH and TDS at least?

I'm trying to figure out why your soil pH is so high to begin with...
 
SNEAKYp

SNEAKYp

Well-Known Member
waktoo said:
What's that mean?

What water was used to mix the soil?

What water was used to keep it moist while it cycled?

Have you grown anything in these soils?

Have you tested the rain water, for pH and TDS at least?

I'm trying to figure out why your soil pH is so high to begin with...
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I used rainwater to mix the soil, TDS was 13 and PH was 7 IIRC. My soil had a high ph from the jump bc the compost and leaf mulch I used was already slightly alkaline and I added lime before I got the initial soil tests back which caused it to rocket up to near 8.

I haven’t grown anything in this yet as the PH was so high it wasn’t worth trying until it was reduced.
 
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waktoo

Well-Known Member
SNEAKYp said:
I used rainwater to mix the soil, TDS was 13 and PH was 7 IIRC. My soil had a high ph from the jump bc the compost and leaf mulch I used was already slightly alkaline and I added lime before I got the initial soil tests back which caused it to rocket up to near 8.

I haven’t grown anything in this yet as the PH was so high it wasn’t worth trying until it was reduced.
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What form of "lime" did you use?
 
getogrow

getogrow

Well-Known Member
i was under the impression that dolomitic lime is more of a buffer then a "ph up" ? it will lower or raise the ph to itself. if dolime takes you to over 8 then i do great at over 8. somehow that dont sound right.
 
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Northwood

Well-Known Member
SNEAKYp said:
CEC: 35.2 meq/ 100 cc
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Nice to see your CEC up, but what's with the meq/100cc units? Isn't cc volume? It was always meq/100g around here, but all the labs I know of here use the newer cmol/kg.

In any case, I'd keep on trying to raise it with additional organic matter, either some mixed in or as with a green manure, or as a mulch which should continually decay and provide you with some stable carbon in there. A high CEC will help increase the pH buffering capacity of your soil as well.
 
Renfro

Renfro

Well-Known Member
I don't know how much truth there is to this but I hear organic growers all the time saying pH doesn't matter in an organic grow.

I do know that the Bluelab Soil pH pen eliminates the guess work as to what the root zone pH is doing.
 
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Northwood

Well-Known Member
Renfro said:
I don't know how much truth there is to this but I hear organic growers all the time saying pH doesn't matter in an organic grow.

I do know that the Bluelab Soil pH pen eliminates the guess work as to what the root zone pH is doing.
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I haven't heard anyone say pH of your soil doesn't matter in an organic grow, but I have heard others say that the pH of your water (for watering) doesn't matter and I think that's true, depending on what is causing it. A soil with a high pH is a sign of high alkalinity and lack of buffering capability. A high pH with your water might be due to high alkalinity or it might simply be due to hydroxide ions formed by the water purification plant to protect us humans from lead poisoning. For example our tap water here has a TDS of around 60, and its pH is over 8.0, so obviously our water has a high pH for the second reason. Untreated well water with a high pH on the other hand likely also has high TDS, and as an organic gardener I would not use it.
 
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Wetdog

Well-Known Member
Renfro said:
I don't know how much truth there is to this but I hear organic growers all the time saying pH doesn't matter in an organic grow.

I do know that the Bluelab Soil pH pen eliminates the guess work as to what the root zone pH is doing.
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You missed the first part of that statement ... In a well buffered soil... meaning getting the pH right from the git go, not chasing it during the grow.

Wet
 
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waktoo

Well-Known Member
ag.umass.edu

Water Quality: pH and Alkalinity

Recently, some growers have expressed concern about the "high pH" of their irrigation water and its potential adverse effects on plants. The purpose of this article is to allay some of these concerns by pointing out the difference between "high pH" and "high alkalinity". Alkalinity and pH are...
ag.umass.edu ag.umass.edu
 
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Northwood

Well-Known Member
waktoo said:
ag.umass.edu

Water Quality: pH and Alkalinity

Recently, some growers have expressed concern about the "high pH" of their irrigation water and its potential adverse effects on plants. The purpose of this article is to allay some of these concerns by pointing out the difference between "high pH" and "high alkalinity". Alkalinity and pH are...
ag.umass.edu ag.umass.edu
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Yup!

Hobby wine makers know that pH doesn't really tell much of a story on its own, which is why they measure titratable acidity using phenolphthalein before and after making adjustments. It's about time that we hobby growers learn the same science. I've seen so many posts saying their pH is shifting so much within a few days after making pH adjustments to their reservoir with up/down. Well doh!
 
getogrow

getogrow

Well-Known Member
Northwood said:
Yup!

Hobby wine makers know that pH doesn't really tell much of a story on its own, which is why they measure titratable acidity using phenolphthalein before and after making adjustments. It's about time that we hobby growers learn the same science. I've seen so many posts saying their pH is shifting so much within a few days after making pH adjustments to their reservoir with up/down. Well doh!
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ph is supposed to shift in hydro. That shift tells us how the plant is uptaking food.
We dont know the exact ph of soil without a lab. so you go purchase lab grade testing equipment or you can just guess , which is what all organic growers do. The difference is huge between an educated guess and a rough guess. As an organic grower , i will just use soil that i know has a decent ph range and it will stay that way for the 2 or 3 months they are in that pot.
 
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Northwood

Well-Known Member
getogrow said:
ph is supposed to shift in hydro. That shift tells us how the plant is uptaking food.
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I mean't a reservoir for water storage, not a recirculating hydro system. But yes, in hydro you'd normally see a slow drift upwards in pH while also showing a corresponding drop in EC unless you're pushing the plants hard to increase transpiration and you've magically reached a balance of sorts. At least that's my take on it.
 
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