General Information


Read all sections of the label before using CYCOCEL plant growth regulant.

CYCOCEL is a plant growth regulator for use on bedding plants and containerized ornamentals in greenhouses, shadehouses, and nurseries. FOR USE ONLY ON ORNAMENTALS GROWN IN COMMERCIAL OR RESEARCH GREENHOUSES, SHADEHOUSES AND NURSERIES. IN PRODUCTION AREAS NOT UNDER COVER, USE IS RESTRICTED TO CONTAINERIZED ORNAMENTALS. DO NOT apply to field-grown ornamentals. CYCOCEL enhances the crops’ aesthetic appeal and improves durability during postproduction shipping and handling. Treated crops are more compact with shorter internodes, stronger stems and greener leaves.

CYCOCEL should be used on healthy plants grown under proper conditions and is not a replacement for good cultural practices. CYCOCEL contains a wetting agent; therefore, additional wetting agents are not needed. An additional wetting agent can be added if desired. If any adjuvants or other chemicals are applied with CYCOCEL, small test areas should be treated first to insure that no crop injury will occur. Plants treated with CYCOCEL may use less water, and irrigation schedules may need to be adjusted to prevent over irrigation.

Field-Grown Ornamentals: Use on containerized ornamentals without impervious floors not permitted by the Arizona Department of Environmental Quality.


CYCOCEL will normally reduce internode elongation for a period of 1 to 3 weeks following spray treatment, depending on crop culture, environmental conditions and plant growth habit. Multiple applications can be applied as needed. CYCOCEL has greatest effect on final plant height when applied at the beginning of rapid stem elongation and will have less effect if applied when shoots are not elongating or at the end of an elongation phase. CYCOCEL application rate, timing and frequency should be adjusted depending on individual grower preferences for crop development.


Foliar spray applications of CYCOCEL often will cause slight yellowing near leaf margins or at the tip of leaves that are small and rapidly enlarging at time of application. The discoloration appears about 3 to 5 days after the spray treatment. Mature leaves at time of spray and leaves formed after application are not affected. Discolored areas usually regain most or all green color by the end of the crop cycle. The degree of yellowing is related to CYCOCEL application rate. The lowest rates do not cause any phytotoxicity or temporary discoloration. Before application rates of 1,500 ppm or greater are used, trials should be conducted to insure that the amount of leaf spotting is not unacceptable to the user. CYCOCEL application rates that are too high may cause brown necrotic areas on leaf margins, which will not recover green color. If the amount of yellowing is too great, CYCOCEL application rates should be lowered to reduce phytotoxicity or temporary discoloration and more frequent applications at lower rates should be made to achieve desired height control.

Users should not apply CYCOCEL near the end of a crop unless they have conducted adequate trials to insure the CYCOCEL rate is low enough to avoid an undesirable appearance during the sales period.


Plant growth and response to CYCOCEL is altered by several factors. The optimum CYCOCEL rate and frequency of application will vary depending on how the crop is grown.


- Crops produced under low light levels and/or high humidity conditions will have a less compact growth habit and will generally require more CYCOCEL plant growth regulant than the same crop produced at higher light levels and/or low humidities.

- Likewise, crops produced at higher temperatures or higher DIF (difference between day and night temperatures) will generally have greater stem elongation and require more CYCOCEL to produce the desired final plant height.


- Crops grown with greater amounts of irrigation, higher fertilization rates, or high amounts of ammoniacal nitrogen will be more lush and taller than crops grown \"harder\" with less irrigation, lower fertilizer, and predominately nitrate-nitrogen. The more lush crops normally require higher amounts of CYCOCEL or more frequent applications.

- Plants that are spaced close together will elongate rapidly when leaves begin to overlap, and more CYCOCEL is needed under these conditions to produce plants with the desired final heights.

- The production schedule for photoperiodic crops and varieties, such as poinsettias and chrysanthemums, influences final plant size, and the amount of chemical needed to achieve the desired final plant height will vary with the production schedule. Crops that are grown under long schedules with more time between planting and start of flower initiation or between final pinch and flower initiation will be taller than crops grown using short production schedules.


- Varieties within a species often vary greatly in their growth habits and the amount of CYCOCEL required for optimum final height.

- Also, colors within a bedding plant series will vary in sensitivity to CYCOCEL.

- Generally, more vigorous, taller varieties require greater amounts of CYCOCEL than do less vigorous, shorter varieties. Users should consult with plant and seed suppliers and breeder companies for information on growth habit of varieties with which the user is not familiar.


The optimum usage of CYCOCEL varies depending on the crop, the individual user's production situation and the desired final plant height and appearance. Users should determine the optimum CYCOCEL rate, timing, and frequency under their individual production situations. Users should obtain experience in small-scale trials under the different conditions where CYCOCEL is to be used before CYCOCEL is used on an entire crop. The CYCOCEL

rates recommended in the label are general guidelines to be used by growers in trials to determine specific, optimum usage appropriate for their operations.


In spray applications, CYCOCEL enters the plant through young expanding leaves, mature leaves and stems. Maximum effect occurs when CYCOCEL is applied to thoroughly cover plant leaves and stems. The spray volume providing thorough plant coverage will vary with plant size and foliage cover.

- For spray applications in shadehouses and container nursery production, apply CYCOCEL at a rate of 1 gallon of spray per 200 sq ft of growing area, regardless of plant spacing. Use 0.5 to 1 gallon of spray per 200 sq ft of growing area for small plants in small containers or plug trays that are closely spaced. A maximum spray volume of 1.5 gallons per 200 sq ft of growing area is recommended for larger plants with well-developed canopies.

- For spray applications in shadehouses and container nursery production, DO NOT exceed the maximum recommended application rate of 3.7 lbs ai/A for single applications and not more than 33.3 lbs/A/year total. Single rates (lbs ai/A) should determine the maximum number of seasonal applications allowed but not to exceed 33.3 lbs ai/A/year.

- Interval between repeat applications to the same crop can range from 5 to 21 days, if required.

CYCOCEL penetrates into the plant to provide maximum effect while the spray solution stays wet. Therefore, greater effect is obtained if sprays are applied under conditions that support slow drying of spray solutions. It is desirable to time CYCOCEL applications so that overhead irrigation or rain will not occur for a period of 6 hours after sprays are applied.

Unless otherwise stated in the section under Specific Perennial Crops, CYCOCEL spray application rates range from 600 to 2,000 ppm depending on the crop and individual user's desired results. The suggested initial CYCOCEL rate for small-scale trials is 1,250 ppm. All references to ppm are based on total CYCOCEL product.


CYCOCEL can be applied as a drench to the growing medium. It is taken up by the plant through the roots and transported to the stem tips where it is active. Drench applications do not cause leaf yellowing and provide longer and more uniform control of stem elongation. In a drench treatment, it is the total amount of CYCOCEL active ingredient applied to each container that determines the reduction in stem elongation. Therefore, users must insure that both the amount of solution applied to each container and the concentration of CYCOCEL in ppm are correct.

Drenches should be applied so that the potting medium is uniformly saturated or non uniform heights will result when there are multiple plants in a container. Apply the drench to a moist medium and not when crops need irrigation. A good procedure is to irrigate crops one day and apply the CYCOCEL plant growth regulant drench the next day.

CYCOCEL application rates for drench treatments range from 2,000 to 3,000 ppm of CYCOCEL. Users should do trials to determine the optimum rates under their particular conditions. The following table gives suggested volumes of dilute CYCOCEL solution to be applied to different size containers.



- DO NOT apply more than 6 applications of CYCOCEL plant growth regulant per production crop cycle (including any BNine tank mix combinations).

- DO NOT exceed 3,000 ppm in a single spray and 3,000 ppm in a single drench application.

- DO NOT apply to plants that are experiencing stress or other production limitations or undesirable plant injury may occur.

- DO NOT apply through any type of irrigation equipment.

- DO NOT apply to plants grown for feed or food purposes.


- DO NOT apply more than 3 applications of CYCOCEL plant growth regulant per production crop cycle (including any BNine tank mix combinations).

- Apply only as a foliar spray. DO NOT apply as a drench application.

- Mechanical (tractor) groundboom, multi-nozzle sprayer applications are not allowed.

- Hand-wand applications to container nursery pots on gravel or landscape barrier fabric production beds cannot exceed one (1) acre of plants per day, per mixer/loader/applicator.

- DO NOT apply to plants that are experiencing stress or other production limitations or undesirable plant injury may occur.

- DO NOT apply through any type of irrigation equipment.

- DO NOT apply to plants grown for feed or food purposes.

Limitations, Restrictions, and Exceptions


CYCOCEL is recommended to improve flowering and to produce compact plants with uniform shoot growth of Hibiscus spp. The CYCOCEL spray application rate range is between 200 and 600 ppm depending on variety growth habit and amount of control desired. Users should start with 460 ppm in trials. CYCOCEL should be applied in multiple applications to produce the most uniform growth. CYCOCEL can be applied once before first and second pinches to produce more compact plants before final pinch. To produce the most compact flowering plants (height less than 18\" in 6-inch pot), applications may be needed after the final pinch, and first application should be made when laterals are 0.5- to 1- inch long. DO NOT exceed 2 applications of CYCOCEL in a crop production cycle. A maximum of 3 growing cycles are permitted

per year.