Sujets généraux

Water for fresh cuts.
I was always taught that when you cut flowers they should be placed in warm water, as it travels up the stem faster( popping any air bubbles)  than cold water.
Now Im reading that you should use cold water.   Which is it??? What is the concensous?

Definitely Cold Water.

Warm water plays host to the existing microorganisms to make them thrive and multiply faster; and it can also damage the Xylem, the structure that draws water into the stem. For longer vase life always opt for Cold water. The air bubbles are not a factor, but you can use Quick Dip on woodier stems if you feel the stems are an issue.

The only exception to that is if you should receive flowers that are very closed and you need them to open fast for an event. In this case, you should still use floral preservative and use only LUKEWARM water (in a pinch warmer water totally works, but note that it WILL affect vase life.) You can also put a plastic bag over the blooms to trap the ethylene gas and the steam. Keep at room temperature. This can help push the blooms to open. To my knowledge, this is the only incidence of using warm water that is useful. 

Once the desired opening has begun, usually 3-4 hours or more, feel free to change the water to cold, maybe rinse the stems, add floral preservative again, then store in the cooler. This assures that any slimy stuff growing in the water is flushed out. That means flowers that last waaaay longer.