Calcitic vs Dolomitic Limestone in Growing Media | PRO …
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calcitic-vs-dolomitic-limestone
Calcitic limestone dissolves faster than
dolomitic limestone so it quickly adjusts a growing medium's pH within one week, but it has a shorter residual effect of up to 1-2 months.
Dolomitic limestone is a combination of calcium carbonate and magnesium carbonate and serves two purposes in the growing medium.
The two most common forms of limestone incorporated into growing media are calcitic and dolomitic limestone:
- Calcitic limestone is calcium carbonate and it neutralizes acids in the growing medium. It provides some calcium, but almost no magnesium. Calcitic limestone dissolves faster than dolomitic limestone so it quickly adjusts a growing medium's pH within one week, but it has a shorter residual effect of up to 1-2 months.
- Dolomitic limestone is a combination of calcium carbonate and magnesium carbonate and serves two purposes in the growing medium. Primarily, it neutralizes acids in the growing medium but also provides some additional magnesium and calcium for plant uptake. Dolomitic limestone dissolves slowly in the growing medium, resulting in longer term pH adjustment (up to 2-4 months) and buffering to improve pH stability.
Promix uses both Calcitic, and Dolomite.
I use
Promix BX. That's also where I got the idea to use both, then researched it.
Together, dolomitic and calcitic limestone create a more even and consistent growing medium pH.
When using both forms of limestone, better pH control can be achieved; calcitic limestone quickly releases and adjusts the growing medium's pH while dolomitic limestone slowly releases over the course of the crop, resulting in limited pH fluctuations during production.
They are best used in a 2/3 x 1/3 combination.