EXCESS PHOSPHORUS and IRON CHLOROSIS

early in the season were less legetative than thobe taken in August and September. The light intensity and light duration to completely keep the standard cultivars vegetatile is 10 to 20 foot-candles for one hour in the middle of the night. A recent experiment on ‘Paul Mikkelsen’ grown at 70’ F revealed that lighting for four hours (10 p.m. to 2 a.m.) with a minimum of 10 foot-candles is necessary to prevent flower bud initiation. This points out that this new introduction is relatively less sensitive to artificial light when compared to standard cultivars. This series of experiments has resulted in the following recommendations to reduce the amount of premature budding in ‘Paul Mikkelsen’: (1) Keep the stock plants vegetative all year by lighting the plants each night with a minimum of 10 foot-candles for four hours in the middle of the night. (2 ) Grow the stock plants a t minimum night temperatures of 70’ F. (3) Do not allow the shoo& of the stock plants to exceed 10 inchez at the time the cuttings are made. If the cuttings are not required at that time. the plants should be pruned to keep the shoots below the minimum length.