Maximizing Results With Collate®

One of the most cost effective option for improving plant structure, preventing early flowering, and controlling excessive plant growth is Collate® (ethephon).  This article highlights some recommendations for getting the most out of your foliar spray applications.

By Brian E. Whipker, North Carolina State University

In greenhouse floriculture production, ethephon is used extensively as a foliar spray to promote lateral branching.   Florel® is a 3.9% active ingredient solution that has been the go-to ethephon formulation for a number of years. Dr. Peter Konjoian conducted extensive research trials in the 1990’s which lead to many of the current greenhouse uses of ethephon.

Another entry into the market is Collate®, which is a stronger, more concentrated 21.7% product from Fine Americas. Greenhouse label uses for Collate® foliar sprays include inducing flowering of ornamental bromeliads, avoidance of stem topple of potted hyacinths, height control of potted daffodils, flower inhibition, increase in axillary shoot development, and height control.  As an example of how Collate can improve branching, in an experiment conducted at North Carolina State University on seed geraniums, shoot number increase by nearly 300% with a 500 ppm foliar spray.

Product Use Tips

Application Parameters. Collate breaks down and becomes inactive with water pH conditions greater than 6.1.  While the registered Collate® products all contain acidifiers, in areas with high levels of alkalinity, the alkalinity will need to be neutralized BEFORE mixing the spray solution.  (A few acidifying products are available, just two examples include Indicate 5 or Phase 5.)  The idea endpoint pH for a Collate® solution should be ~4.5 to 5.0.

Temperatures.  In addition, Collate® activity is linked to active plant growth. Applications made when temperatures are below 60F (15.5C) or higher than 95F (35C) will be less effective.

Timing.  When used to promote axillary branching, the plants should be well rooted in the container.  Typically rooting to the side of the pot will occur within two weeks.  For prevention of early flowering, it should be noted that the last application should be make 6 to 8 weeks prior to the intended sales date.  Late applications will result in flower delay.

Suitable application windows should also be noted with stock plants.  Ethylene can inhibit rooting, so applications should not be made within 7 days of harvesting cuttings.

Avoid Applications to Stressed Plants.  When used correctly, Collate® applications will result in enhanced plant growth.  Because ethylene produced by Collate® is a stress enhancer, it is important to have the plants actively growing and not under suboptimal conditions (heat, drought, environmental, or disease stress).  Lower leaf yellowing typically occurs when Collate is applied to water stressed plants.

Optimal Concentrations.  For most plants, spray rates are typically at 500 ppm.  Complete spray coverage is required because Collate® is not translocated in the plant.  This is especially important for plants such as garden mums.  Incomplete spray applications will result in uneven growth and flowering.

Phytotoxicity.  Some cultivars have a greater sensitivity to Collate®.  Cupping and distortion of the young expanding leaves can occur.  In addition, over application can also result in distortion and leaf bleaching or spotting.

Protective Equipment and REI. Collate® is a minor eye and skin irritant.  Thus because of this, it has a longer REI of 48 hours.  In addition, it should be noted that eye protection is required, along with protective gloves, coveralls, apron, shoes, and headgear for overhead applications.

These tips will help you effectively incorporate Collate into your production program.  With Collate’s cost effectiveness and use for improving lateral branching, it is a valuable tool to include in your PGR toolbox.


Figure 1. Growth control of seed geraniums with Collate foliar sprays at 500 ppm.

Figure 2.  Branching is increased by almost 300% with 500 ppm Collate foliar sprays.

Figure 2. Branching is increased by almost 300% with 500 ppm Collate foliar sprays.

Figure 3. Phytotoxicity can occur if the plants are stressed when ethephon is applied or rates are too high.

Figure 3. Phytotoxicity can occur if the plants are stressed when ethephon is applied or rates are too high.