This technique provides elevated daytime temperatures, increases the humidity and minimizes the amount of water applied during rooting. If possible, provide a root zone temperature range of 70-75 F during propagation. Calcium and magnesium are normally applied by blending dolomite at the rate of 4 to 10 pounds per cubic yard of potting medium to adjust the pH to approximately 6.0. The amount of dolomite used will depend upon the initial acidity of the medium. Light level range for good nursery growth and dark green leaf color is 1500 to 4500 foot-candles.
Severe defoliation can occur if plants are permitted to dry excessively.
Control - Prevent exposure to chilling temperatures in production areas or during shipment. Plants usually recover slowly from this type of injury. Have all heating equipment properly vented and maintained prior to heating season. Also, avoid drought conditions. Control - Use sterilized or new and well drained potting medium.