February 2025 - 15

CEA
different ethephon rates from zero to 750 ppm. Also, three
carrier water alkalinity options were studied, with five air
temperatures ranging from 57° F to 79° F, in three species:
petunia, geranium and verbena.
Alkalinity
Tap water alkalinity was adjusted using sulfuric acid.
Plants were grown under the same temperatures, then
moved into greenhouse compartments with varying
temperatures and kept there for 24 hours after spray
application because it can take up to 16 hours for the
plant to fully absorb the ethephon.
High alkalinity definitely reduced efficacy, with plants
growing larger than the control and flowers buds visible.
Temperature
Temperatures were set two hours before spray
application and maintained for 24 hours after. At 79° F,
ethephon was not effective at all. Results prove that
temperature has a dramatic effect on ethephon, especially
when it's applied as a spray.
Here are some pro tips for ethephon to improve efficacy:
* If your carrier water has a high alkalinity, especially
if you're located in the Midwest, you need to add
buffering solution to reduce the pH, such as sulfuric
acid, or an adjuvant such as Indicate Five.
* Only apply ethephon when your greenhouse
temperatures are below 75° F. Increasing the relative
humidity can keep the ethephon from drying up too
quickly. Maintaining a vapor pressure deficit around
7.7 kilopascals is useful, but again, always conduct
your own in-house trials.
* Allow the solution to dry slowly over a minimum of
four hours to enhance the uptake; it can take 12 to 16
hours before the plant fully absorbs the ethylene.
* If you plan to use ethephon to remove flowers and/
or buds for timed flowering at retail, be sure to refine
your timing from application to reflower so it lines
up with shipping/market dates. In-house trials are a
huge help here to nail down your specific production
timing needs.
* Ethylene is a senescence hormone, so never apply
it to plants that are already stressed. For example, a
drought-stressed plant that gets an ethephon spray
may go into further senescence, losing more leaves.
* Remember, this PGR has one of the longest REIs
(restricted-entry intervals). Protective equipment such
as eye protection, coveralls and apron shoes should be
worn because it's a minor eye and skin irritant.
Mix your way
to stronger plant sales.
JRM Chemical, Inc.
Half Page Horizontal
Save money and improve your product: Soil Moist is the choice
for your business. Learn more today at www.soilmoist.com.
Call 800.962.4010.
Free Hang Tags available for your treated plants
GREENHOUSE PRODUCT NEWS 15
Adding Soil Moist to your potting soil mix is the ultimate
boost for healthy plant sales.
Soil Moist water-management polymers help produce strong, vibrant plants
that require less water and labor - a growing solution that delivers
real advantages:
* Reduces plant waterings by 50%
* Ideal for hanging baskets and container plants that dry out quickly
* Helps improve your margins and controls costs
* Decreases plant loss - at the retail level
* Improves plant shelf life - reduces customer returns
http://www.soilmoist.com
February 2025

Table of Contents for the Digital Edition of February 2025
