how much Dolomite Lime?

m3d1c1n3man

Well-Known Member
I'm thinking of mixing up some FFOF with 20% perlite and some dolomite lime. How much dolomite lime do you think is good as a percentage? Any other additives recommended?
 
i know what its for, i was wondering why you think Ocean Foret needs to be adjusted since you are just mixing it straight from the bag? whats the pH now? I use OF 90% of the time as my base mix and never have added dolomite due to my opinion, that OF is pretty good straight from the bag. But different strokes.
 

m3d1c1n3man

Well-Known Member
i know what its for, i was wondering why you think Ocean Foret needs to be adjusted since you are just mixing it straight from the bag? whats the pH now? I use OF 90% of the time as my base mix and never have added dolomite due to my opinion, that OF is pretty good straight from the bag. But different strokes.
yea but it's not going to hurt to mix in a few tablespoons of lime to keep the ph steady
 

Uncle Ben

Well-Known Member
I wouldn't but then again I find out what I'm using before doing any adjustments. Does FF have dolomite in it already? Most potting soils do to counteract a low pH. If you're hell bent on adding dolomite, then add some and see what happens.

UB
 

m3d1c1n3man

Well-Known Member
I wouldn't but then again I find out what I'm using before doing any adjustments. Does FF have dolomite in it already? Most potting soils do to counteract a low pH. If you're hell bent on adding dolomite, then add some and see what happens.

UB
no FFOF does not contain any dolomite lime, but it does have "oyster shell (ph adjustment)" as a final ingredient. but as far as i know the lime is more to help keep the ph steady in a middle ground rather than to swing it some way.
 

Jimdamick

Well-Known Member
Potting soil usually has a neutral PH of 7 out of the bag, but adding synthetic nutes will change that over time ( you don't have to worry that much if you are organic). If you PH your soil after 4 weeks of feeding, you can bet it is out of wack, probably too high for pot plants. The lime stabilizes it at a neutral level, which In my opinion is very important. I use it for that reason.
 

fridayfishfry

Well-Known Member
my book says 1cup per cuft. most potting soils do have low ph thanks uncle ben. you can't add too much lime(dolomite)(and don't get the pellitized that is for lawns), the ph won't go higher than 7. it's just a waste to add more and can get cakey. i really don't know why it's not added to more potting soil, it's $5 for 40lbs around here anyways that's a lot of cups
 

Wetdog

Well-Known Member
*I* use 1cup/cf of dolomite lime. 2TBL/gallon is equivalent.

Have no idea about FF or any other bagged mix for that matter. 43 years ago I traded sweat labor to learn to make a soiless mix from scratch and eyeball it. Just never saw the need to buy something I could make better and cheaper. Now, I get my kid to do the shovel work.:hump:

From what I've heard, FFOF doesn't have enough OSF for the entire grow cycle and runs out in mid flower. This could be so, or could be something else entirely. IDK and I'm damn sure not going to shell out $25 for a bag to find out.

Dolomitic lime is cheap, ~$4.50/40lb bag here, pulverized or pellets. Calcitic lime (equivalant to OSF), is $16/30lb bag. OSF, after shipping is ~$46/40lb bag. Needless to say, no experience with OSF.

Wet
 

ShLUbY

Well-Known Member
when i was mixing in lime i was using it at 1/4cup per cuft when i was using age old organics nutes (has some synthetics). it definitely kept my soil Ph between 6 and 7. in my experience when you have too much lime in your soil the Ph will be around 6.9-7 and never go below that all the way to harvest. the right amount of lime will let the ph fall slowly through flowering so by the time you harvest Ph will be 6.2-6.4 or so because it has dissolved and leached out of the soil.

however, in my experience what is more important while using lime is keeping the soil saturated properly. it's all about CEC. each time you water, a little of that lime dissolves and regulates Ph. i was using slightly undersized pots for my plants, 4 gal packed to the top. i would water so that i got 10%-20% runoff every time (when using partial synthetic nutes). ensures proper saturation, and that much water going through will dissolve and carry away some of the lime every time. I was getting my containers to dry out every other day from being very slightly undersized. so i was watering heavily every other day. this increases CEC, because it doesn't happen without water! a more frequent watering led to a bigger harvest for me in the end. when i had containers that took 3-4 days to dry out the harvest was diminished. i believe this was due to the roots absorbing what was around them, but then slowed down absorption when the water (containing nutrients) was used up around the roots, but the soil still remained moist in other places. the smaller sized pots let me kind of get them rootbound, so they would dry up faster and i could water more frequently.

if you're going all organic... the oyster shell will help control PH, and if you wanted to add lime, i would add no more than 1/4cup lime per cuft. but that was my magic number... it may not be for you. also all organic with proper microbe population and the oyster shell should help keep the Ph steady where you want it anyway. I'm gettin ready to do a run with the vegamatrix line to get some plants through flower while my living soil is cooking. there is no lime in my mix, i did add oystershell at 1/2cup cuft. other than that i'll be relying on my microbes to keep the soil in check!
 
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