Dolomite is added to growing medium to raise pH to a range of 5.5 – 6.5 and to supply plants with calcium and magnesium needed for healthy growth.
Dolomite differs from Lime sand and Limestone in that it contains magnesium as well as calcium. Dolomite is used to supply both of these elements and is a very effective neutralizing agent. As a rock it should contain between 8-12% Magnesium as Mg and 18-22% Calcium as Ca. Dolomite also slowly dissolves in the growing medium over time, helping to counteract the acidifying effects irrigation or tap water can have on the growing medium pH. The best quality dolomite is sourced from limestone type rock, and requires crushing and screening.
In most if not all growing media we must alter the pH, generally by applying calcium in the form of limestone. However we believe that the pH of the media is like a temperature gauge it tells you the acidic state of the growing media, but it doesn’t tell you what is causing the problem. It is well documented that the elements of calcium, magnesium, sodium and potassium all influence the pH of the soil. Magnesium is also up to 2.5 times as effective at neutralizing acidity than calcium.
Because of these factors we process our raw Dolomite so it is within our guidelines
Note: It is important to understand that adding Calcium is greatly beneficial to the plant but this must be balanced with Magnesium and Potassium or the balance becomes off and it does not have the full effect within the plant for optimum plant growth.