Hi Gang, 1. I'm still confused about the sunshine vs. warm water notion of reducing damage to plants that have gotten too cold. Wives' tale or note, the notion persists and some folks seem to have good luck by pouring water over their plants before the sun shines on them. I can't figure it out. 2. I like the term I first encountered in email from a South African email friend. It was immediately obvious what she meant when she referred to a "black frost." 3. In the absence of ice forming nuclei (e.g., tiny particles), water can supercool to about -38 C, the homogeneous nucleation point. Dissolved salts or sugars can depress this temperature a few degrees more. Thus, with or without "antifreeze" type solutions, trees (not sure about bulbs) can prevent ice crystals from forming in their cells if they can achieve supercooling of their cellular liquids (apoplast and symplast). There is some correlation between the northern limit of certain trees, and the homogeneous nucleation point. It is proposed (but I don't know if it's true) that some species are limited in their northward ranges because -40 C is about the limit for this effect. Oddly, some evidence indicates that water can supercool to -70 C under laboratory conditions. Pehraps some plant out there can perform such a trick, but I've not hear of it. 4. To survive temperatures lower than -40 C, plants may resort to dehydration, pulling water out of their living cells. This my be the antifreeze-like effect that has been mentioned because water outside the cells freezes and serves to pull even more water out of living cells, leaving their cytoplasm ever more saturated with proteins, lipids, sugars, etc. The reason ice can "pull" water out of cells is that frozen water has a concentration of zero, in terms of liquid water, and water moves from higher concentrations (i.e. inside cells) to areas of lower concentration. Just think of the water pulled out from foods in some freezers-eventually foods can become nearly freeze dried. I think dehydration mechanisms are responsible for the survival of some plants (not all plants) in areas where they are routinely exposed to temperatures below -40 C (or so). 5. The heat of fusion refers to the extra energy that must be released by water if it is to freeze. As was mentioned, sprinklers over citrus can often be useful because the ground water keeps hitting the leaves and even freezing. However, the whole process keeps all the ice at about 32 F (0 C) even when air temperatures might be in the mid- to low-20s. As long as you can keep new water freezing on plants you can generally keep the plants at about 32 F. If no new water arrives the ice on the plants, and the plants too, will continue to cool to ambient temperatures. Ground water offers two benefits: 1) it brings some warmth with it (perhaps it is 40-50 F) and it has energy to release (heat of fusion) before it will freeze. LINK: Enthalpy of fusion, Wikipedia http://en.wikipedia.org/wiki/Enthalpy_of_fusion/ LINK: Supercooling Water to -70 C http://geog.ubc.ca/crpoints/papers/… Cordially, Joe Conroe TX, where a bit of cool weather would be appreciated.