Abstract: A test kit for determining the `total compost life`, and chemical stability of a moist compost sample, includes a transparent container for holding the compost sample, and a reactant mass, located within the container in the space not occupied by the compost sample. The reactant mass includes a pH basic reactant material, and a color change indicator material, responsive to pH changes in the atmosphere within the container. After the moist compost sample is charged into the container, the container is sealed and allowed to remain undisturbed for a prescribed time period, e.g., about three (3) hours. During this time, carbon dioxide (CO.sub.2) and volatile organic acids are emitted from the sample into the space surrounding the chemically reactant mass. The pH basic reactant chemically reacts with the emitted carbon dioxide (CO.sub.2), in ionic form, or the emitted volatile organic acids, so as to produce a color change. The nature of the color change is an indication of the carbon dioxide (CO.sub.