Richters InfoSheet D2281  

Directions for Using Ethrel to Enhance Echinacea Germination

We are indebted to Neil Reese of South Dakota State University for sharing this protocol for germinating Echinacea angustifolia seeds.

The protocol has only been tested on E. angustifolia, though it is possible other species may benefit also, especially E. pallida. It is important to realize that some seed lots of the same species can behave quite differently. We have had some lots of E. angustifolia germinate well without any pregermination treatment, while other lots require treatment.

What is Ethrel?

Ethrel (also Ethephon) is a trade name for 2-chloroethylphosphonic acid, a compound that slowly releases ethylene gas. Ethylene gas is a naturally occuring plant hormone that is associated with fruit ripening, among many other normal plant functions.

Directions for Use

Sow seeds in usual sterile seeding mix. Water using a 1 mM solution of ethrel (1 mM = 1 millimolar = 1 gram powder in 6 litres of water). Enclose seedflat in plastic bag and place in a refrigerator for 2 weeks. Arrange for the refrigerator light to stay on 24 hours a day. Water with the ethrel solution if the sowing medium shows signs of drying. After 2 weeks, expose seedflat to room temperature and normal light. Germination should be complete in 2-4 weeks.

Where to Get Ethrel?

CANADA: Plant Products (905-793-7000) sells Ethrel under the trade name “Ethephon”.

CANADA and U.S.A.: Sigma Scientific of St. Louis (1-800-325-3010) will sell small quantities to any address in Canada and the United States. The catalogue number is C0143 and the listing is under 2-chloroethylphosphonic acid. The smallest quantity available is 100 mg.

Is Ethrel Considered Organic?

Not likely, but check with your organic certifying agency for a ruling. If your agency allows artificial hormones such as “Stimroot” then probably it will allow Ethrel.


We welcome your feedback on your experiences with Ethrel and germinating echinacea seeds. The information you provide will help us refine our recommendations to other growers and herb enthusiasts. Please email your comments to Infosheet Feedback.


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D2281   ©1995-2000 Otto Richter and Sons Limited


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