# pH shift /organic soil grow/time for lime??



## Delta9 (Jul 17, 2014)

Im currently in about the 4th week of flower with 3 plants in soil
-my pH right throughout the grow until now has sat bang on at 6.5

3 or 4 days ago I noticed one plant in particular displaying lots of pale green leaves 

then 2 days ago I fed my plants a compost tea and after then the pH has gone to 6.0 -which I realise is borderline..

So I really want to keep on top of this-and have researched a possible solution for using dolomite lime-but I am confused at what quantities to apply. I also understand it is a little slow acting, and that hydrated lime acts faster but seems generally not recommended.

Either way I don't want to sit on this too long without a fix and thereby lock out nutrients to my plants[and buds] at such a crucial phase..

What can I do? 

I will put some pics up tomorrow in the light of day-my plants are sleeping right now..

Any suggestions in the meantime are very welcome.


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## Rosebud (Jul 17, 2014)

Are you in an organic soil now? If so, i grow organic and have never ph'd  anything. 

Looking forward to the pic's.


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## The Hemp Goddess (Jul 17, 2014)

Did you add lime to your mix originally?  My understanding is that with organics you do not need to be concerned with watching/checking/adjusting your pH unless it is way out of whack because the soil feeds the plants.  I am wondering if the light gredn is due to the fact that you are 1/2 way through flowering and they are getting N depleted?


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## Delta9 (Jul 17, 2014)

The Hemp Goddess said:


> Did you add lime to your mix originally?  My understanding is that with organics you do not need to be concerned with watching/checking/adjusting your pH unless it is way out of whack because the soil feeds the plants.  I am wondering if the light gredn is due to the fact that you are 1/2 way through flowering and they are getting N depleted?




*THG* I think you might have hit the nail on the head there- the more I read on the subject the more this points to _exactly_ that issue - Light green new growth and yellowing of older fan leaves. 
For some reason I expected that to happen later in the flowering period- like in the last couple of weeks of flower. And yes -I did add dolomite lime to my original pot mix - about 1 cup to 1m square from memory.

Sounds like *Rosebud* concurs with you too regarding not needing to worry too much about pH in soil- thats a completely new concept for me-so thanks for helping me understand that both of you!

My pH of 6.0 is still within an acceptable range then- so thats cool for now.
I understand that plants in flower require less N than in veg- and that too much N in flower can lock out other nutrients from being absorbed- so is it necessary to counteract the nitrogen deficiency at this stage?


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## ShOrTbUs (Jul 17, 2014)

what are you using to ph the soil? and have you ever added anything to adjust your ph during the grow?


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## shahomy (Jul 18, 2014)

> hydrated lime acts faster but seems generally not recommended.


i just bought a 50lb bag of this stuff yesterday...looks like enough for about 50 years...why is it not recommended?
should i not use it?


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## Dman1234 (Jul 18, 2014)

I dont know what hydrated is but I never put dirt in a pot without dolomite lime, also i sometimes give a good veg feeding (hi in N) a couple weeks into flower if i know its a 9 or 10 week flowering strain. jmo


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## Hushpuppy (Jul 18, 2014)

Hydrated lime is all calcium, you don't want to use that as it will cause lockout due to having too much calcium present. The dolomitic lime has a small amount of calcium but mostly Magnesium. You can get pulverized or powdered dolomite lime and mix it into the soil then water in (or you can mix it with water and add it the next time you water) as it sounds like the pH has dropped too low for organic (you want to be around 6.5-6.8) and possibly lacking in magnesium. How much you use depends on the amount of soil you have for each plant. How big are the pots you have your plants in?

I found that Espoma makes a lime that is micro pellet and is a nice mixture of calcium, magnesium, and a couple micro elements. It dissolves quickly in water and you can get it at Lowes/home depot/home garden stores.


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## The Hemp Goddess (Jul 18, 2014)

I really like Espoma products.  That is the lime I use also Hushpuppy.


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## Hushpuppy (Jul 18, 2014)

cool  I just bought another bag of it for my new little grow that I just recently started


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## shahomy (Jul 18, 2014)

> Hydrated lime is all calcium, you don't want to use that as it will cause lockout due to having too much calcium present. The dolomitic lime has a small amount of calcium but mostly Magnesium


So, dolomitic lime is different than hydrated lime? Both words are on the bag i bought...guess i`ll have to see if i can find a breakdown of what`s in it...



> you don't want to use that as it will cause lockout due to having too much calcium present


Ugg... i already applied a spoon full last nite...top dressed and watered in on 5 gal. smart pots, medium is humboldt sphagnum peat moss...


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## pcduck (Jul 18, 2014)

Hydrated is baked lime.
Very fast reacting.


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## The Hemp Goddess (Jul 18, 2014)

Isn't hydrated lime what they use to make concrete?


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## ShOrTbUs (Jul 18, 2014)

The Hemp Goddess said:


> Isn't hydrated lime what they use to make concrete?



indeed it is.  usually mixed with cement and sand. that stuff is nasty, use with caution. it will burn you, blind you, and can kill if you inhale too much.


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## Delta9 (Jul 18, 2014)

ShOrTbUs said:


> what are you using to ph the soil? and have you ever added anything to adjust your ph during the grow?



I've never used anything to adjust my pH- I added dolomite lime to my pots when I originally planted my seedlings and nothing since then.


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## Delta9 (Jul 18, 2014)

Hushpuppy said:


> Hydrated lime is all calcium, you don't want to use that as it will cause lockout due to having too much calcium present. The dolomitic lime has a small amount of calcium but mostly Magnesium. You can get pulverized or powdered dolomite lime and mix it into the soil then water in (or you can mix it with water and add it the next time you water) as it sounds like the pH has dropped too low for organic (you want to be around 6.5-6.8) and possibly lacking in magnesium. How much you use depends on the amount of soil you have for each plant. How big are the pots you have your plants in?
> 
> I found that Espoma makes a lime that is micro pellet and is a nice mixture of calcium, magnesium, and a couple micro elements. It dissolves quickly in water and you can get it at Lowes/home depot/home garden stores.



Ok thanks Hush -thats interesting to know. I potted in 12 litre poly bags-but there is only probably about 9-10 litres of soil in there..
My original thought regarding the paler leaves was magnesium deficiency and I added Epsom salts when I last watered-that has'nt changed anything in the 5 days since. I think THG might have nailed the problem as Nitrogen deficiency-it's frustrating-I took a bunch of pics but the lighting doesn't really illustrate the issue very clearly. I'm gonna have to work the settings out on my camera.


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## pcduck (Jul 18, 2014)

The Hemp Goddess said:


> Isn't hydrated lime what they use to make concrete?



That and many other building supplies. Farmers also may use it on their fields around here. Mostly in the Fall.


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## The Hemp Goddess (Jul 18, 2014)

Delta9--I gave my early flowering girls a dose of blood meal today as I think I am having some N problems also.  I have read that it breaks down fast and it is all N.  I'll let you know if I experience any adverse effects.


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## Delta9 (Jul 19, 2014)

The Hemp Goddess said:


> Delta9--I gave my early flowering girls a dose of blood meal today as I think I am having some N problems also.  I have read that it breaks down fast and it is all N.  I'll let you know if I experience any adverse effects.



Thanks *THG* I appreciate that - I look forward to your results
-good luck


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## Hushpuppy (Jul 19, 2014)

Here are a couple pics of Magnesium deficiency that are the usual giv-aways: 

View attachment user141080_pic834017_1328769965.jpg


View attachment user141080_pic834021_1328769965.jpg


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## pcduck (Jul 20, 2014)

> Hydrated lime is all calcium,



This is incorrect. Depends on the lime used.

 There is also hydrated dolomitic lime.



			
				National Lime Association said:
			
		

> Lime is a generic term, but by strict definition it embraces only the manufactured forms of lime&#8212;quicklime and hydrated lime. It does not include limestone, which is the feedstock for lime manufacturing.
> Quicklime, the product of calcination of limestone, consists of the oxides of calcium and magnesium, and in the United States it is available in three forms:
> High calcium quicklime--derived from limestone containing 0 to 5 percent magnesium carbonate.
> Magnesian quicklime--derived from limestone containing 5 to 35 percent magnesium carbonate.
> ...


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## Hushpuppy (Jul 21, 2014)

PC: everything I have seen on "hydrated lime" and what is offered for sale is total calcium based, while "dolomitic lime" that I have seen is Magnesium based. I have never seen hydrated dolomitic lime but I guess technically you are correct. So I guess the key here is to look for Dolomitic lime, or should I direct them to you first so that you can give them the specifics?


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## pcduck (Jul 21, 2014)

HP...Like nearly everything in this growing of mj, it is quite hard to give specifics. Some use lime and some don't. I feed the soil and reuse my soil, and use very little lime. While others use hand fulls. When I use hydrated dolomitic I use even less because of how fast it works.

IMO the use of lime is over used by many. If you mix your soil correctly a grower should not need hand fulls to maintain the pH. Plus all that calcium builds up in the soil and locks out other nutrients.

The 50# bag in the pic below is hydrated dolomitic lime. It will last me 2 lifetimes of growing in the amounts I use. With some left over. 

View attachment IMG_20140721_184616_273.jpg


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## shahomy (Aug 19, 2015)

> The dolomitic lime has a small amount of calcium but mostly Magnesium.


Not trying to nit-pic, seriously I`m not....but my bag of Espoma "organic"  garden lime says 21% calcium and 10% magnesium, anyway...


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