Temperature - The ideal temperature range for cuttings is 72°F - 80°F.
It is always better to have the root zone temperature at 76°F - 80°F while the canopy is kept at 72°F - 80°F.
The warmer rooting zone helps produce roots quicker, while the cooler canopy minimizes transpiration from the leaves.
If the rooting zone is too cold, especially during the winter months, then the cloning system should be placed on a heating mat that has a thermostat control set to 80°F. In winter, when the water temperatures in the pipes are cold, take care to allow the water to reach room temperature before adding it to the cloning system. Cold water on the cuttings or young roots will shock the clones and retard their rooting abilities. For the summer months keep the water temperatures below 83°F; failure to do this will cause the cuttings to rot. The higher water temperature increases the growth rate of root rot pathogens. Warmer water also holds less dissolved oxygen which is needed by the cutting. Lower dissolved oxygen always favors root rot organisms. If you notice that your cuttings are becoming slimy and soft make sure that these cuttings are removed immediately. This rot will spread to the other cuttings very quickly.