Old Reviews Soil pH/lime/toxicity questions

[Bayes]

Recently, there have been/are a few active threads on soil pH and lime.

I have some questions that weren't answered in these threads but did not want to hi-jack a member's thread.


Here goes:


1. If you are setting up your pots 2-3 weeks in advance, is there an INITIAL pH reading that is so low that the soil should not be used?? (Any soil's pH can be raised, but at what price?) Potential issues down the road could be death to the "microherd" , greater susceptibility to calcium and mag. toxicity, etc. and just "funky" stuff, mostly bad, that could result later.


2. Let's suppose you pre-treat your soil with 1.5 Tablespoons/gallon of pulverized dolomitic line (Soil Doctor in this case) which has 30% calcium, 20% magnesium.

- Is there any reason to use Cal-mag supplements during the grow as a preventive measure? Is there greater danger (due to limed soil) in creating a cal-mag toxicity if you use regularly?

-If feed water is borderline high in calcium (not just TDS), should a grower be even more concerned about possible calcium toxicity if soil is limed. What is a safe level of calcium in well water?


3. Is there a maximum safe dosage of lime? Suppose after 2 weeks, 1.5 T was not enough to bring pH to 6.5, is it okay to add more? How much more is safe?


4. What effect does flushing (3x water or with a surfactant, e.g., Sledgehammer) have on limed soil?

I know from reading that calcium toxicity is very rare although personally I'm not sure its rarity is that all that great for those of us that lime their soils. Of course, a big variable is strain...

Thanks in advance--

 

[Bayes]

I am disappointed in the lack of responses.

 

[bad dragon bzzz]

thats a lot of technical and detailed info you seeking.one for the experts I would say.sometimes they have weekends off too.

 

[thecuch]

You have some very specific questions and there is alot of them.... your lack of responses is prob cause it is the indoor growing forum...instead of [h=1]"Fertilizers And Soil"[/h]

 

[briman]

Hey Bayes, Ill get thi in the hands of a mod. Sorry nobody has checked in on ya and your disappointment. Hold tight and someone will be with ya in a bit.

 

[briman]

What brand of soil are we talking about? Store bought bagged, home made mix, or TLO, soil less? That would help for starters.

 

[Bayes]

It happens to be Happy Frog and OF, equal measure, w/perlite. The pot/soil I am readying for my next grow reads 4.8 (accurate 8, double checked with Hanna combo, triple checked w/drops.) I have a grow underway (Wild Thai Rider with journal) that ALSO started at 4.8 but had to use almost 2 T/gallon of lime to get the soil to 6.5. IMO, it developed calcium toxicity. (I did not modify my cal-mag dosing until late in the grow and my well water is a little hard (TDS of 300). I believe that it is the combination of high lime, cal-mag supplements and well water which by itself would not (has not previously) cause a problem resulted in a a "perfect storm". Of course, I could be wrong. Before posting yesterday morning, I had already decided to sht-can the soil based on my current experience with a Wild Thai Ryder grow (journal is up).

I posted ONLY to have someone who is better known/respected address this issue because IMO it can be a problem and not just due to flocculation. I wanted my post to be a catalyst for someone else to comment.

 

[briman]

Sorry I couldn't be of service. I do know that OF has had its fair share of problems in the past with low PH. It sounds like you already have someone in mind that is, "better known/respected address your issue". There is the option to PM them and get your answer. I will however say, that the terminology of, "I wanted my post to be a catalyst for someone else to comment', can be taken as confrontation. Please feel free to PM whom ever you choose to get your answer. It would probably be the best and quickest way to get the answers you are looking for.

 

[Saneone]

Use Hydrated Dolomite Lime and add it to luke warm water and water your plants with it heavy like if you were going to flush it will raise the ph or wood ash, bone meal, crushed marble, or crushed oyster shells will help to raise the soil pH try to crush it into a fine powder to avoid the time relese effect as much as you can

 

[The Elvis]

Ill try based on my grows.

I have some questions that weren't answered in these threads but did not want to hi-jack a member's thread.


Here goes:


1. If you are setting up your pots 2-3 weeks in advance, is there an INITIAL pH reading that is so low that the soil should not be used?? (Any soil's pH can be raised, but at what price?) Potential issues down the road could be death to the "microherd" , greater susceptibility to calcium and mag. toxicity, etc. and just "funky" stuff, mostly bad, that could result later.

calcium and mag. toxicity will not be as bad as low acidic PH.

2. Let's suppose you pre-treat your soil with 1.5 Tablespoons/gallon of pulverized dolomitic line (Soil Doctor in this case) which has 30% calcium, 20% magnesium.

- Is there any reason to use Cal-mag supplements during the grow as a preventive measure? Is there greater danger (due to limed soil) in creating a cal-mag toxicity if you use regularly?
Ive never herd of dolomite lime really hurting soil unless used way way to much.

-If feed water is borderline high in calcium (not just TDS), should a grower be even more concerned about possible calcium toxicity if soil is limed. What is a safe level of calcium in well water?
I don't know why you feel like lime is so toxic? I know some is but not garden lime.


3. Is there a maximum safe dosage of lime? Suppose after 2 weeks, 1.5 T was not enough to bring pH to 6.5, is it okay to add more? How much more is safe?

I use 3 cups garden lime to 1.5 yards of OF also 3 cups of Epsom salt 3 cups of per-lite

4. What effect does flushing (3x water or with a surfactant, e.g., Sledgehammer) have on limed soil?
this is a good thing \. I flush my OF in the shower with no Sledgehammer and i get alot of the salts out. i do this after 30 days or flower. Sledgehammer flushes to hard or to much at 30 day flush ..

I know from reading that calcium toxicity is very rare although personally I'm not sure its rarity is that all that great for those of us that lime their soils. Of course, a big variable is strain...

you are correct..

Thanks in advance--[/QUOTE]