Materials such as castor, cottonseed, linseed, woodash, tobacco stems, greensand and ground rock potash supply potassium. Each product will vary in its level of potash along with the decomposition rate. Broadcast lime to reduce a soil s acidity. Lime sweetens the soil, while adding Calcium and Magnesium. Apply gypsum when more calcium is required without increasing the pH. Natural sources include limestone, dolomite, shells and marl.
Dolomite has higher levels of calcium and magnesium.
Grind all forms finely to be beneficial for plants. Always test the soils pH with a portable test kit. Apply lime at least a month before planting. Organic fertilisers also include vital trace elements. Used under License.