The chemical growth regulator Florel can be used on crops of pinched poinsettias to optimize branching after a manual pinch. Growers can take advantage of the effects of Florel in any or all of the following ways.
1. The uniformity of branching can be enhanced resulting in an increased number of fully developed branches contributing to the quality of the plant.?
2. The number of branches resulting from a manual pinch can be enhanced as treatment allows the plant to reach its fullest branching potential.?
3. More compact growth results as internode elongation is inhibited while the plant is under treatment.
The recommended concentration is 500 ppm that is obtained by mixing 1.6 fluid ounces (fl. oz.) of Florel per gallon of water. Use of a graduated cylinder marked in milliliters (ml) makes measuring small volumes easy. Conveniently, 1.6 fl. oz. equals 50 ml. When either fractions or multiples of one gallon are mixed the round number of 50 ml. can be divided and multiplied easily and accurately whereas measuring fractions or multiples of 1.6 fl. oz. is difficult.
Growers should trial Florel on a small scale before treating an entire crop. Some growers have found 300-350ppm (1.0-1.1fl. oz. per gallon, 30-35 ml. per gallon) to be the concentrated range that works best as it carries less risk.
Use of a surfactant (spreader sticker) is recommended on poinsettia due to its waxy leaf cuticle. Capsil, or a similar product, can be used according to the manufacturer’s recommendations. Complete, uniform coverage is essential, as Florel is not readily translocated inside the plant. One gallon of spray solution should be applied to 200 square feet of crop area that equals a spray to drip application.
Research has shown that the most effective treatment strategy is to apply two Florel applications around the manual pinch. The first application should be made approximately three days before pinching and the second approximately one week after pinching. The stimulation of branching is thought to be associated with the elevated ethylene level in the plant at the time of pinching. Therefore, getting ethylene into the tissue just prior to the pinch and again just after the pinch insures the necessary pressure to optimize branching.
Florel should be applied to poinsettias during the time of day when chance of plant stress is minimal. Avoid applying during the late morning to early afternoon period as high light and temperature can be stressful. Apply late in the afternoon or on a cloudy day.
Apply to actively growing plants
Ethylene is a plant stress exaggerator. Only apply Florel to poinsettias that are actively growing. Do not apply to plants experiencing stress of any kind. Instead, determine the source of the stress, correct it, and then apply when plants have resumed active growth. Some common stresses to avoid during the summer with poinsettia include low moisture, high temperature, high light, improper nutrition, poorly developed roots, and so on. If Florel is applied to plants experiencing stress the ethylene often leads to an exaggeration of the normal symptoms of the stress.
In addition to Florel’s branching effect on poinsettia, it also affects growth as a traditional growth regulator. While under treatment internode elongation will be inhibited resulting in more compact growth and shorter stems. If other growth regulating products are used to control final plant height fewer applications may be needed. The recommended Florel treatments before and after pinching may replace the first application of a traditional growth regulator or delay its timing.?
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