Nitrate/Nitrite Testing in Compost

Nitrate nitrogen levels will vary according to the time of year. During the summer, nitrate should be around 350 ppm. In the winter, nitrate in compost will fall to about 100 ppm. Finished compost should always have less than 500 ppm nitrate regardless of the time of year, as the majority of nitrogen is bound up in organic protein until needed by the plant.

There should be no nitrite nitrogen in finished compost, this is a toxic product for the soil!