How much are the roots compromised at an ec of 1.5-2.25 when poinsettias are allowed to wilt? Not a major wilt, yet not a slight wilt. Soil is nearly dry, leaves starting to droop. I realize your responses may be more of an opinion than fact.

Thanks

Are you describing a one time event or a consistant dry down as a growing tecnique?
If you fear soluble salts burning of the roots or foliage I'd go in with a fresh water irrigation. This has happened to me once in a great while as I have no employess and get caught not being able to water the crop fast enough on hot sunny days as the Poinsettias get larger but have never experienced damage at the EC levels you describe if your measurements are by the pour thru method ....Michael Pawelek

Constantly with acceptable salts. Drying down to control fungus gnats and other root diseases. Curious how it affect roots.

I run higher SS than what you describe so I wouldn't have the guts to try dry down to slight wilt on a regular basis though you might take a small portion of the crop and experiment. Have you tried Zerotol to
"clean up" the upper layer of soil and get rid of the fungus gnats. I'm using it with great results this year. I do not know if it would be effective though with a drip system as you have to pretty well inundate the whole top of the container to really clean the soil up.
Michael Pawelek

Greenthumb -

Which method are you using to test the EC levels? Acceptable levels will vary depending on the method used to test because of the different amounts of water used for each test. Because the most water is added with the 1 to 2 test the acceptable range is 0.7-1.3. If you used another method your levels are actually in good range.

The effects of high soluble salts in the media on the plants may leave the plants more susceptible to root rotting pathogens. High EC can also result in leaf and bract edge burn and inhibit plant growth. If the roots are damaged from excess levels it can also lead to reduced nutrient uptake in less than sufficient quantities which will also lead to poor plant growth.

Those ec results were from a lab. I am more concerned about the root health being compromised from drying down with ecs in an acceptable range. I like to see them wilt a bit, therefore I use less PGRs. But, I have noticed a few roots on plants that did wilt have died, no pythium yet, but they don't look as good as plants which haven't dried out. I had a huge loss last year from pythium and and kept up rather well on fungicides. I was curious if the drying down was detrimental to the roots thus contributing to my problems last season. Thanks

Poinsettias can actually tolerate a fairly high EC level as long as they are not allowed to dry out while the levels are high. If you have maintained an acceptable range and felt that you did the same last year, then allowing the plants to dry down a little between waterings is actually beneficial for a number of reasons. It is a good way to control fungus gnats and reduce the plants' susceptibility to root rotting pathogen. It is also a good way to tone growth and reduce the need for growth regulating. As long as your levels are in the acceptable range it is unlikely that allowing the plants to dry would make them more prone to a Pythium but likely that other factors may need to be considered. We are hearing more about resistant strains of Pythium. Did you change water sources or media last year when the problems seemed worse than previous seasons? Thanks!