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adding dolomite lime to pure peat?

bw420

Member
Got a question for you guys. How much dolomite lime should i add to say 1 gallon of pure canadian peat moss. picked up a bag the other day and wanna use it as part of a soil mix but i need to ph it first. Says its around 3.8 to start out. Ive got the fine powdered type of dolomite. consistency of flour id say. I was thinking around 1tbs per but am not sure. I know some peeps use that much in pro mix when adding other ammmendments and pro mix allready has some amount of lime in it. so maybe more then 1tbs per? thanx for any help.

late. :joint:
 

sproutco

Active member
Veteran
I would think at most 1 1/3 tablespoon per gallon of peatmoss. 10 pounds per 27 cubic feet or 1 yard max lime rate. .13 cubic feet in a gallon .13/27 x (10 pounds x 12 fluid ounces per pound x 2 tablespoons) = 1.16 tablespoons. If your fertilizer is highly acidic you might need this much lime. If your ferts are more alkaline you would use much less. Adjusting your fert water with an acid or base and adding calcium and magnesium makes liming less important. Better to underlime than add too much. PH is good at 5.6 to 6.2 in soilless grows so this is sort of low.
 
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bw420

Member
thank you.

I should elaborate a bit. Im going to be using this "limed" peat to add as a part of a organic soil mix. that along with mushroom compost and chunky coco coir and some perlite will make up the mix. Then illl be adding ammendments to the soil and letting it set. So there will be quite a bit of organic ammendments in the soil that will contributing to the lowering of the ph. some include,

worm castings, kelp - bone - blood and cottonseed meals, green sand, glacial rock dust and some guanos for the appropriate stages. Im actuallly experimenting with growing outdoors in pots over the winter. its very very mild here. thanx for the help.
 

sproutco

Active member
Veteran
When I am trying out a new mix and adding lime, I might make 3 or 4 small batches using the same ratio of ingredients except varying the lime rate. Place in small cups. Wet well. Wait a week. Test ph. Then, pick which lime rate worked best.
 
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BurnOne

No damn given.
ICMag Donor
Veteran
Powdered dolomite lime should always be added at the rate of 2 tbs/gal of mix. Whether the mix is pure peat or peat/perlite/wc/whale shit and boat anchors. The dolomite has to be in that concentration to provide calcium and magnesium.
Burn1
 
V

vonforne

You should always use 2 tbls per gallon unless you are using FF or something with lime already added. The FF OF I use has crushed oyster shells to control the PH. I add one tbls per gallon and my PH sits a 7. Lower your water PH to 6.0 and everything should be fine. If theres not lime in your base mix add the 2 tbls. per gallon.
 

bw420

Member
Thanx guys. Just the info i was hoping for. Allready mixed it up and i did go with your suggestions. thanx again.

Late. :joint:
 

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