The Virtues of Dolomite Lime

[Clovenhoof]

"Around my parts the native soil is very alkaline, lots of limestone in the area"

Hey master shake, if this is true, why would you want to add more limestome? There should be Mg and Ca plenty enough. The deficiencies can be a sign of too much and nutrients are locked off.

 

[master shake]

"Around my parts the native soil is very alkaline, lots of limestone in the area"

Hey master shake, if this is true, why would you want to add more limestome? There should be Mg and Ca plenty enough. The deficiencies can be a sign of too much and nutrients are locked off.

Sorry, I should have been more clear...Since the native soil is so alkaline finding pH up buffers is difficult. I mainly grow indoors with peat based soil so I need the lime. My main question is if I should use more of the espoma garden lime because it is somewhat cut with clay or if I should switch to regular limestone. When I'm outdoors I add no lime. Thanks Cloven

 

[Ulysses]

Guys- seek out Pulverized Dolomite Lime.

Pelletized Lime- even pelletized dolomite lime is (#1) coated with a polymer making it even harder to break down, and (#2) it creates tiny pockets of lime because it's not fine enough- "lime affects only the small volume of soil surrounding each lime particle. A given volume of lime contains more particles if it is finely ground and thus affects more soil than coarser limestone", (#3) pelletized lime varies greatly in quality...

I used Espoma Garden Lime for years and continued to get poor results thinking it was my nutes, soil, weather, water or some other variable. I came to ICMag and BurnOne recommended pulverized dolomite lime and I have been using it with great results since- nice dark green leaves and vigorous growth...

As I have stated, if you're indoors, and unwilling to create your soil mix a few months in advance, you are better off using Cal/Mag suppliments and monitor your pH manually.

 

[stevefrench]

"i have no idea how long they have been there... should it be okay to use?"

Hey stevefrench, from my theoretical understanding this should be ok as long as the lime didn't come in contact with water - but I could be wrong.

i doubt it touched any water, figured it should be okay i just wanted to double check.

free lime!

 

[Blue Dot]

As I have stated, if you're indoors, and unwilling to create your soil mix a few months in advance, you are better off using Cal/Mag suppliments and monitor your pH manually.

Incorrect. As said you can add dolo to your mix and use right away. Your pH will quickly settle at a certain pH depending on how much dolo you add. If you add too much it will settle at pH 7.0 and you won't be able to budge it once it's there.

If you look at this graph here you can see that if your dolo is powdered finely enough then in even just 1 month the pH can rise from 5 to 6 which is a large jump.:

It may be true that you need to add a cal/mag supplement to increase your Ca and Mg but cal/mag is NOT Ca CARBONATE and Mg CARBONATE.

It's the carbonates that affect the pH. The actual Ca and Mg ions have zero effect on the pH.

The whole reason of adding dolo is to buffer your soil to a certain pH.

The effect of adding Ca and Mg (by adding dolo) to your soil is just an incidental bonus.

 

[VerdantGreen]

Hi VerdantGreen, a buffer's properties are that in its buffering zone the pH only slowly changes when adding acids and bases, but it still changes. For reasonable quantities of adding acids/bases your statement is true, but you can overdo it. And limestone itself is basic, so adding a lot means raising your pH to higher levels.

hey clovenhoof, agreed, im sure it is possible to overdo it - i said that i had read that it was hard to overdo it, so a bit extra should be ok.

as for the buffering properties - surely dolomite lime will not raise the pH above 7 or it would not be a buffer? i thought the pH of dolomite lime was 7.
from wiki "A buffering agent adjusts the pH of a solution. The function of a buffering agent is to drive an acidic or basic solution to a certain pH state and prevent a change in this pH."
were you talking about regular lime or have i got it wrong?

 

[Clovenhoof]

Hi VerdantGreen,

oh you're right, I mixed things up (hehe, this happens if you try to write things late in the night :-D). I'm not sure, if this changes anything, but a quick glance through wiki could not help me explain my thoughts behind this. So I look further to clarify this. Thanks!


"as for the buffering properties - surely dolomite lime will not raise the pH above 7 or it would not be a buffer? i thought the pH of dolomite lime was 7."

Wait. The buffering system's pH is 7. The pH of dolomite lime can be somewhere else, it is not necessary to be the same.




"from wiki "A buffering agent adjusts the pH of a solution. The function of a buffering agent is to drive an acidic or basic solution to a certain pH state and prevent a change in this pH.""

This is somewhat unprecise. 'Prevent' is a kinda too strong expression, it is true for reasonable quantities of adding acids or bases, as I wrote in the above posting. But not in an absolute meaning so as if the pH is frozen to a certain pH. You still can change it. And if it's true, that limestone is basic* then you change your pH by adding more and more. These are two properties and not connected with each other.

*this is the only thing we have to find out. My chemical knowlegde is too limited to help me in that point, but maybe a proper chemist can chime in.

 

[VerdantGreen]

i thought the pH of dolomite lime was 7. Not sure if it's basic, i think rather that it just reacts with acids, and the reaction neutralises acid and releases cal and mag (its been a while since school

so i suppose strictly speeking dolomite is not a true buffer, because it will not correct a high (alkali) pH back to neutral.

in my experiment on page 1. the pH change slowed right down as it approached 7.

regular lime would be more alkali though as far as i know

 

[Clovenhoof]

"so i suppose strictly speeking dolomite is not a true buffer, because it will not correct a high (alkali) pH back to neutral."


You have to look at it the other way round. You first have to have a buffered system (that means that a buffering agent is added and the pH is in the buffering zone). Then you can add bases and pH remains around 7. Or add acids and it still remains in the near-neutral range. It only holds pH in a distinct area on the pH-scale, but if you have added too much alkaline or acid substances it goes to higher or lower values.

 

[Blue Dot]

You guys are missing the point.

If you add too much dolo your pH WILL settle at 7.0 and your little bit of acidic fert added every other watering will not budge this pH.

Plants don't like 7.0. They like 5.9-6.5 in soilless so Don't overlime your soil!

 

[Blue Dot]

If you want your pH to settle around 5.8 - 6.2 then you should go out and buy an appropriate size mesh 40-80 and shift all your dolomite thru it then add it to your soil(less). I would then add 10-15% 100 mesh lime to that to stabalize the pH for the first couple of weeks to a month.

 

[maxx8246]

Maan I definitely need to buy some dolomite lime, is it good for tomato plants as well?
O and by the way VerdantGreen I think you've taken the verse from the Bible out of context: It is written

Then God said, "I give you every seed bearing plant on the face of the whole earth and every tree that bears fruit with seed in it. They will be yours for food."

 

[przcvctm]

You guys are missing the point.

If you add too much dolo your pH WILL settle at 7.0 and your little bit of acidic fert added every other watering will not budge this pH.

Plants don't like 7.0. They like 5.9-6.5 in soilless so Don't overlime your soil!

You covered particle size and effectiveness over time very well. Thank you for those graphs.

I'm sure my lime is 100 mesh. That's all I have. So, how much is too much per gallon? Are you and Judas Cohen taking exception to the recommended 2 TBLS/gal or just making a statement in general that too much is not good?

 

[VerdantGreen]

O and by the way VerdantGreen I think you've taken the verse from the Bible out of context: It is written

Then God said, "I give you every seed bearing plant on the face of the whole earth and every tree that bears fruit with seed in it. They will be yours for food."

hi maxx!
food can be for the mind, the body or the soul...

the exact quote changes with different Bibles.

V.

 

[judas cohen]

przvctm: I'm saying too much and/or not enough is bad. 1-2 TBL/gal soil is an excellent amount of DL "IF" (and only if) your soil mix needs it and/or your tap water is not pH 7+. It depends on several variables.....pH of: water, nutes, soil, soil/soiless amendments, is soil being recycled, strain being grown, etc.

Foxfarm bagged grow mediums are all perfect pH outta the bag. Very often if you add DL Ocean Forest/Light Warrior and have high pH water, you will have serious problems. If recycling Foxfarm grow mediums that contain peat moss, you should add some DL. If a bagged soil contains peat moss and no oyster shell or DL and water is 7-, you will often need something for pH up and DL is a good choice. (NOTE: There is ZERO DL in FFOF and LW from the factory, they use oystershell for pH and Ca.)

Most packaged organic ferts have enough Ca and Mg, but not always. Often water has enough Mg and Ca for reefer. Read the labels of your grow medium and ferts and/or use pH meter or drops. It's also true that organic grows with lotsa microlife will automatically eliminate pH problems.

DL is good stuff, but IMO, more grows are damaged by too much DL rather than not enough DL. DL is not a Magic Bullet in all cases, and if misused, it can really screw up your garden.

 

[przcvctm]

Edit...

Thanks for the answer, jc.

 

[LlamaSchool]

Thanks, U.

 

[piratejack]

I have two types of lime available locally...

One is pulverized limestone with a ratio of 21% calcium and 12% magnesium, and the other is "coarse" dolomite lime with a ratio of roughly (cant remember) 45% calcium and 35% magnesium.

I purchased the pulverized limestone since its finer and has the 2:1 ratio I see recommended. Should I purchase the actual dolomite lime even though its coarse? can i grind it up in a blender? Should I still use the 2 TBS per gallon ratio with the pulverized lime?

I will be using other rock powders and amendments that should help with the calcium & magnesium, plus I have pretty hard water. Just wanted to make sure I shouldn't get the other lime before mixing this batch this weekend.

Any help is mucho appreciated. Peace

P.

 

[VerdantGreen]

i think the one you got will be fine jack

 

[rupertb]

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