To optimize the management of fertigation in the soilless crops is essential to know the behavior of chemical variables of the solution, and of the substrates. The aim of this study was to determine the behavior of pH, electrical conductivity (EC), cation exchange capacity (CEC) and carbon nitrogen ratio (C:N) in tree substrates base on burned rice husk and coconut fiber; and pH and CE in the drainage, in a soilless system to carnation crop cv. Delphi, with three recycling percentages and in different phenological developmental stages. The trial was carried out with three different substrates base on burned rice husk (BRH) and coconut fiber (CF). A randomized complete block experimental design in a split plot with nine treatments and three replications was used. The pH leachate tends to decrease towards the end of the crop, and in substrates this variable was kept constant over the period, although increases along with BRH percentages. The EC was significantly higher with 100% of recirculated leachate and in treatments with lower BRH content; unexpected, EC in substrates was significantly lower in treatments with more CF. On the other hand, CEC was significantly higher in substrates with higher CF percentages. However, contrary to literature, the C:N tended to show higher values in the substrate with higher BRH content. ; Para optimizar el manejo del fertirriego en los cultivos en sustrato es indispensable conocer el comportamiento de pH y conductividad eléctrica (CE) de las soluciones así como la capacidad de intercambio catiónico (CIC) y la relación carbono/nitrógeno (C:N) de los sustratos. El objetivo del presente estudio fue determinar el comportamiento de pH, CE, CIC y relación C:N de tres sustratos a base de cascarilla de arroz y fibra de coco; y pH y CE en los drenajes, en un sistema de cultivo con tres porcentajes de recirculación en diferentes estadios de desarrollo de plantas de clavel estándar cv. Delphi. Se utilizó un diseño experimental de bloques completos al azar con nueve tratamientos y tres ...