how much dolomite lime to use

az2000

Well-Known Member
I don't want to argue. You agree peat moss drops ph as it ages. You agree that aging nutes lowers the ph. This isn't multiplication where 2 negatives becomes a positive. If they both go down individually they will go down faster together.
At any given point of time (after watering), yes. Peat will cause ph to be lower as will an accumulation of nutrient salts. However, comparing one point in time to another, the later one will be higher.

You introduced the time variable. Then said you haven't measured soil ph. Eliminated the time variable. And, now complain that this is off topic.

I just wanted to make sure the OP knew which direction his/her medium's ph would travel. I felt it was as on-topic as you did when you mentioned something you haven't even measured.

You may have the last word.
 

GOLDBERG71

Well-Known Member
I just think it's amazing that you believe this. The peat moss will only break down faster the older it gets. As the plant in that soil ages along with the peat moss breaking down faster and faster the higher and higher the amounts of salts are being added. Add this together you believe It raises the PH. So if my pro mix is PH neutral when I start and it is. This is why some of us choose this medium. That's 7.0 and we never add nutes higher than 6.7. After 3 months you believe the PH OF THAT SOIL will be greater than the 7.0 it started at? I'm a simple man and I try to apply logic to everything. This sounds highly illogical to me.
 

GOLDBERG71

Well-Known Member
Which one of these things is responsible for the miraculous rise in PH. The degrading peat moss. Or is it the build up of salts? Because the power of the lime that was added when that cutting was transplanted has stopped working by the end of the plants life?
 

az2000

Well-Known Member
I just think it's amazing that you believe this. The peat moss will only break down faster the older it gets. As the plant in that soil ages ....
Just to clarify, I was referring to the time variable you used: "Since the ph drops as the plant dries."

When I said "at any given point in time" I was referring to between waterings, not between seedling and harvest.

You may continue having the last word. I just wanted to point out that important detail.
 

GOLDBERG71

Well-Known Member
The reason I use perlite is because that also is PH neutral. So that can't be the cause for the phenomenon.
 

GOLDBERG71

Well-Known Member
It is a much less crazier of an idea with limiting the time frame down to one water cycle. That very well could be true when the plant is young. But when that bad boy is 6 weeks into flower being fully feed. And that lime has run it's course that reading will be lower. If not your not using dom. lime your using pellets and probably more than we were talking about.
 

az2000

Well-Known Member
The reason I use perlite is because that also is PH neutral. So that can't be the cause for the phenomenon.
I use perlite too.

I still disagree with that logic. But I do believe you said at anytime
Is this what you are referring to:

At any given point of time (after watering), yes. Peat will cause ph to be lower as will an accumulation of nutrient salts. However, comparing one point in time to another, the later one will be higher.
I agreed with you that peat causes acidity as do nutrients. But, that's a relatively long-term process. What I referred to (as you did) was between waterings, "as the plant dries."

If not your not using dom. lime your using pellets and probably more than we were talking about.
For the record, I use fine/flour-consistency calcitic and dolomitic lime, about a 50/50 mix. I use 2 Tbsp/gal. I don't agree with using pellets. I don't believe the lifespan of MJ is long enough for the pellets to have an effect.

"Because the acids in soils are relatively weak, agricultural limestones must be ground to a small particle size to be effective. The extension service of different states rate the effectiveness of stone size particles slightly differently.[12] They all agree, however, that the smaller the particle size the more effective the stone is at reacting in the soil.[13] Measuring the size of particles is based on the size of a mesh that the limestone would pass through. The mesh size is the number of wires per inch.[14] Stone retained on an 8 mesh will be about the size of BB pellets. Material passing a 60 mesh screen will have the appearance of face powder. Particles larger than 8 mesh are of little or no value, particles between 8 mesh and 60 mesh are somewhat effective and particles smaller than 60 mesh are 100 percent effective."
-- http://en.wikipedia.org/wiki/Agricultural_lime

Using flour-consistency lime, I've never "run out" that I could see.
 
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az2000

Well-Known Member
I forgot about the lime losing its effectiveness over that 3 month timeframe as well.
I've got a funny feeling the way you feed at a higher ph (for the wrong reason, that the medium acidifies as it dries between waterings) probably prevented you from encountering the fact that the pelletized lime isn't doing much for you.

What I mean is, that higher-ph feeding holds your medium higher -- instead of the lime. Not a bad thing to do. It's just that I think you fell into it with an assumption about what you're soil does between watering, and then never had as much reason to hit a critical ph problem resulting from slow-acting pelletized lime.

Just a theory.
 

GOLDBERG71

Well-Known Member
I've got a funny feeling the way you feed at a higher ph (for the wrong reason, that the medium acidifies as it dries between waterings) probably prevented you from encountering the fact that the pelletized lime isn't doing much for you.

What I mean is, that higher-ph feeding holds your medium higher -- instead of the lime. Not a bad thing to do. It's just that I think you fell into it with an assumption about what you're soil does between watering, and then never had as much reason to hit a critical ph problem resulting from slow-acting pelletized lime.

Just a theory.
Your OBVIOUSLY not reading thoroughly or your bulb isn't bright. I DONT USE PELLETS. I'm signing off this thread for good now. Rule of thumb do what works for you and your situation. I'm not just talking about in between waterings you are. I'm talking about from the time I put my cuttings into a 5 or 7 gallon pot. I go from cutting straight to the finishing pot so I don't get any transplant stress or delays. I don't want to have wait for my plants to adjust for a 2 week period or so. So it will be in that pot and for at least 3 months. If I'm running some of my hazes. They will be flowering alone for 3 plus months.
 
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LemonDropette

New Member
I think you have that backwards. Doesn't PH rise as the soil dries. That's what I observe with Pro-Mix HP using a $50 soil ph probe.

I'd strongly recommend the OP monitor their runoff as well as invest in a Control Wizard Accurate 8 soil probe.
Hey Azz2000..I know its an old thread but your comments have mattered to someone out here..and signed up just to reply to you. Your details were exactly what I needed and very detailed.. And learned from the miscommunications of buddy.. So thank you :). I have health issues so sometimes i give a little more water to cover an extra day id i think it will be too dry (not overwatering either.) I reused my pro mix hp after washing it out and using gaia green 444 in veg for my first group of clones. Im cooking the rest for their transplants with a big variety of rock dusts etc..followed a diverse recipe. My bf was paranoid of calmag deficiency so added into his tea but i decided to wait and watch. One of my clones that has been in pro mix plus topdressed about 2 weeks ago and rust spots occurred so i thought maybe my promix phs are off.. I aim for 6.2. I have not added lime but have dolomite lime and its been added (about 1/4 cup in 100 liters/25 ish gals and brewing nearly 2 months so hoping to use soon. The plant with rust spots (room temp is cooler around 21 day/17.5C night, rh sucks between 30-38% and i cant refill my tank as my stairs kill me.. its dry as hell in canada right now.. Good airflow and doubt its rust mold. No other plants out of 12 have it. 2 leafs have it on the same aide of a top. It does have some weird new growth and internodal spacing is stubbier than The other same plant cut..not that i expect it to be identical.. Im worried my watering pH is t good for the lack of lime now. I will put Mg in my next tea and with your advice keep my waterings on the higher pH side consistently. Do you think i should topdress dolomite lime? Im so sketchy to use it.. If i dont hear, its old i. Not holding my breath :p i will wait to see what the Epsom salt does first. New growth was a bit light but improved with topdress 444 and its still growing. I tipped it once and thought maybe it was stressed as growth slowed..the. The green new growth..then rust spots within 3 weeks. I've seen one rusty leaf before on synth nutes but it resolved..
2nd question: my brewing living soil with promix base, should i aim for the 6.7-7.0 for living soil or go a but lower as its the majority of the base? I used about 20% worm castings, 20% perlite, then kelp alphalfa rocks and etc etc.

Im open to discussion and want my first living soil to be rockin'
 
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