Cultural
Prior to unrooted cutting arrival, ensure the propagation environment is sanitized by cleaning propagation benches, floors, and mist nozzles. The propagation environment should be free of algae, pests, and weeds. Ensure that you have an action plan to prevent and control disease and pest entry during propagation. Determine your propagation substrate, liner tray, rooting hormone, and surfactant supply is adequate, therefore reducing the likelihood of shortage. Determine initial propagation substrate pH and electrical conductivity (EC) for low or high pH or EC problems. During propagation, monitor propagation substrate pH and EC by performing 1:2 Extraction, SME, or PourThru procedures. For mums, optimal substrate pH is 5.8 to 6.2 and substrate EC should remain below 1.5, 3.3, and 3.3 mS/cm, based on the 1:2 Extraction, SME, or PourThru methods, respectively.
Environmental
Prior to cutting arrival, ensure that your mist system(s), humidifiers, shade or energy curtains, and/or fertilizer and acid injectors are properly working and calibrated. Once cuttings have arrived, stuck, and placed in the propagation environment, begin misting to rehydrate cuttings. It is important to remember mist is not and should not be used as a form of irrigation. Adjust and reduce misting intervals upon callusing, root initiation, and root formation. Too much mist can delay rooting, cause stretch, and rot. Maintain a daily light integral (DLI) of 10 to 12 mol·m-2·d-1. To do so, one may have to deploy shade or apply white wash to the greenhouse glazing material during summer months. High DLIs during propagation will produce higher quality rooted cuttings, but too high of light can become detrimental. Shading the propagation environment will assist in temperature management and control. Maintain an air and propagation substrate temperatures of 70 to 72 ºF.
Source: eGRO Blog (W. Garrett Owen)