In response to Ecke's comment about letting poinsettias dry down to enhance root growth, how far is dry enough? Do you want to see slight wilt? Moderate wilt? EC was 1.5 SME. Thanks!

If the plants are well established and actively growing a slight wilt every so often is probably alright as long as the EC levels are not too high. We would never want to see moisture stress to the point of wilt on young plants!

Letting the top 1/2 inch to inch of soil dry between irrigations is probably adequate. The soil surface should be dry to the touch and you should have to stick your finger down into the soil a little to feel moist soil. You should also get in the practice of lifting the pots immediately following irrigation and later when the pots have dried and the plants are crying for water. Soon you'll get the feel for when to water without allowing the wilted plants to tell you.

Hope this helps!