Proper Plant Growth Regulator Use

Proper PGR Use

Jim Barrett, Environmental Horticulture Department professor at the University of Florida, is one of 15 speakers scheduled to present at the 26th annual Pest & Production Management Conference taking place February 25-27 in Orlando, Fla.

Barrett will be discussing plant growth regulator (PGR) use, a topic he briefly discussed recently with Greenhouse Grower as the February 25-27 conference approaches.

What are the latest PGRs to hit the market and how would you rate their effectiveness?

In terms of size control products, Topflor is the latest product to be introduced and we have done a great deal of work with it. Topflor is a very flexible product that can be used in a wide range of situations. It is active as both a spray and a media drench. Topflor works well on crops sensitive to PGRs and it also can be very good in situations where a lot of control is needed. ConTego will be introduced this year for use in reducing drought stress. It can be very effective and I will discuss strategies for its use.  Another new product is Configure, which is used to promote branching and growers are finding interesting ways of using.

If there’s one PGR application technique or “rule of thumb” most growers should be using yet are not, what is it?

Probably the strongest recommendation I would have for most growers is to learn to use the PGRs earlier in the crop. Applying the PGRs earlier makes it easier to finish the crop at the desired size with less chemical used late in the crop, which then provides the consumer with a plant that performs better. An example would be drench or dip treatments of liners prior to transplanting plugs or rooted cuttings.

Are there any new PGR research developments in regard to poinsettias?

In the past few years we have evaluated using Topflor and Bonzi as drench applications at low concentrations early in the crop. Growers who have tried this early drench strategy have been very successful with it. The early drench gives the grower more options in the use of PGRs and is especially useful on vigorous varieties or on tall crops after the spray cutoff dates. The principle carries over to other crops, and I will discuss some of the Topflor early drench work we have done with seed impatiens and Wave Petunia baskets.

For more information on Pest Management Conference, presented by Society of American Florists and Greenhouse Grower, visit

Leave a Reply

2 comments on “Proper Plant Growth Regulator Use

  1. Any grower recommendation for the use of topflor
    label instructions seems to be very vague.

    Any info to share
    Custom Grown Greehouses

  2. Any grower recommendation for the use of topflor
    label instructions seems to be very vague.

    Any info to share
    Custom Grown Greehouses

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