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TheUrbanFarmer · February 24, 2016

Well, based on the Ca:Mg ratio - that standard 2:1 - that is likely dolomite limestone.

If you are chasing that golden ratio of 7:1 to 10:1 Ca:Mg - dolomite will never get you there before you end up with too much Mg and locking out K. Ideally, you want your soil to have about 65% calcium...which comes from many different sources outside of your liming amendments.

You are better off going with a more pure calcium carbonate source like oyster shell flour (western US) or aragonite (eastern US). These amendments can impact soils positively for up to 5 years where a standard ag lime or dolomite is often applied yearly to control pH.

Where I live the native soils are sandy loam and therefore tend to leach Mg rather quickly. I offset this by using other amendments like gypsum and sul-po-mag.

Given the media you say you are using, you can assume, 1c of lime per cu ft of peat moss to bring the pH into the proper range.

February 24, 2016	#9
TheUrbanFarmer Tomatovillian™ Join Date: Jun 2015 Location: Zone 8a Posts: 64	Well, based on the Ca:Mg ratio - that standard 2:1 - that is likely dolomite limestone. If you are chasing that golden ratio of 7:1 to 10:1 Ca:Mg - dolomite will never get you there before you end up with too much Mg and locking out K. Ideally, you want your soil to have about 65% calcium...which comes from many different sources outside of your liming amendments. You are better off going with a more pure calcium carbonate source like oyster shell flour (western US) or aragonite (eastern US). These amendments can impact soils positively for up to 5 years where a standard ag lime or dolomite is often applied yearly to control pH. Where I live the native soils are sandy loam and therefore tend to leach Mg rather quickly. I offset this by using other amendments like gypsum and sul-po-mag. Given the media you say you are using, you can assume, 1c of lime per cu ft of peat moss to bring the pH into the proper range. Last edited by TheUrbanFarmer; February 24, 2016 at 11:38 AM.