Pennsylvania Flower Growers #216
A major objective of the bedding plant grower is to consistently produce petunia plants which are com pact but vigorous, and have several basal branches bearing a large number of flower buds just beginning to open at the time of sale. These qualities are more easily obtainable as a result of intensive breeding of F, hybrids. The newer Fj hybrid petunias tend to be naturally branching, early flowering, and to some degree remain compact. However, the control of light (intensity, quality, and duration), night temperature, and the use of growth retardants such as B-Nine provide the grower with his best tools for obtaining maximum quality with these F} hybrids. It was the purpose of a recently completed study at Penn State to evaluate the effects of various photoperiods, artificial light, B-Nine, and night temperature in selected combinations on the growth and flowering of petunias. A series of three experiments were conducted in which the effects of the environmental factors were analyzed using from two to eleven petunia cultivars representing multiflora and grandiflora habits of flowering (Table 1). Each experiment was separated into three phases: Phase A included the period between seed germination and transplanting; Phase B, lasting three weeks, began with the application of photoperiod treatments after transplanting; Phase C followed Phase B and lasted until plants were harvested.
Keywords: Environmental factors Plant growth Artificial Light Germination night temperature