It is manufactured commercially by alkaline extraction of brown coal (lignite) leonardite and is used mainly as a soil conditioner.

[1] The extraction is performed in water with the addition of potassium hydroxide (KOH), sequestering agents, and hydrotropic surfactants.

The resulting liquid is dried to produce the amorphous crystalline like product which can then be added as a granule to fertilizer.

High quality oxidized lignite (brown coal), usually referred to as leonardite, is the best source material for extraction of large quantities of potassium humate.

Less oxidized brown coal contains a higher proportion of the insoluble humin fraction and along with peat which is lower in humic acid content and usually high in ash content requires separation by filtration or centrifugation to remove ash and humin.