The use of burnt rice husk (BRH) as a substrate in the cultivation of carnations in the Bogota plateau has increased greatly in recent years. Carnation has a relatively long crop cycle and throughout the growing season an intensive and continuous fertigation is supplied. Changes in physicochemical characteristics of the substrate that occur throughout the crop cycle are not fully known and therefore the present study aims to evaluate the behavior of certain parameters of burnt rice husk substrate throughout the carnation crop cycle (100 weeks)