For years, an alleged life hack has circulated online to supposedly help people maintain their Christmas trees. According to the rumor, the trees will keep their needles for longer periods of time if people hydrate them with hot water.
This persistent claim has existed online since at least 2007 and shows no signs of disappearing. In December 2024, the claim surfaced again across Facebook (archived) and Threads (archived), among other social media platforms.
(Facebook user KindredJoy)
For example, one post read:
"FOR all those families with real Christmas trees.....I learned something interesting from the farmer and his wife.
- Before watering your tree......boil the water first, let stand for 5 minutes and then water tree! This with keep the sap from getting hard and allow for the water to go up the bark! Cold water clogs the openings with the sap and your tree will die much quicker!
- Christmas tree lesson #101. Enjoy your tree well into the new year!!" ?????????
Thanks to Daria
Credit goes to the first owner ✍️
Another post (archived) claimed that the hack had worked, reading:
So I saw this post from a tree farmer that said when you water your Christmas tree that you should boil the water and than let stand for 5 minutes before watering your tree and it will last much longer than it would if you use cold water. Cold water makes the sap gum up and clog the end of the tree. Welp I have done it since I saw the post and just saying they are right this is the 3rd time I have had to give my tree water in a week's time and just saying I fill it just about all the way
However, it has not been possible to prove whether this purported life hack actually works or makes a difference to the appearance of a harvested Christmas tree. There were credible sources speaking both for and against the use of hot water, and, due to those inconclusive findings, we rated the claim unproven.
Some Experts Recommend Hot Water
Several credible sources say you should pour hot (not boiling) water into the base of your Christmas tree, including the State University of New York College of Environmental Science and Forestry, the North Carolina Christmas Tree Association (archived) and the Great Swamp Greenhouses garden center (archived).
These "pro" sources argued that hot water helps increase water uptake by melting built-up sap on the trunk, which, in turn, helps keep the tree looking nice for longer periods of time.
Fresh Cut Tree Bases Are More Important
However, we also found credible sources saying that the temperature of water used to hydrate Christmas trees does not affect water uptake.
In 2012, Rick Bates, a professor of horticulture at Penn State University, spoke to NPR about tips and tricks for maintaining Christmas trees, telling the "Talk of the Nation" program that:
Cold water is fine. What does matter is the fresh cut on the base of the tree. If it's been, you know, a day or so since that tree has been harvested, putting the fresh cut opens up those pores that are going to draw in the water. And if the water is cold or hot, it doesn't matter so much as having a fresh cut and no sap covering that base of the trunk.
Scholars Gary Chastagner and Eric Hinesley supported this statement, writing for the National Christmas Tree Association, "The temperature of the water used to fill the stand is not important and does not affect water uptake."
Chastagner and Hinesley are both respected academics in the field of Christmas tree research.
Asked via email in December 2024 whether he still thinks that water temperature doesn't make a difference to the health of a tree, Hinesley confirmed his opinion, adding: "Gary Chastagner and I never found anything to be better than plain water alone. And there is no need to boil it before use."
Hinesley further supported Bates' statement that making a fresh cut off the trunk of the Christmas tree, usually about 1/2 to 1 inch thick, helps water uptake.
In any case, Hinesley said the most important factor in keeping a harvested Christmas tree looking nice and lasting was providing it with ample water, a claim also repeated in previous research:
When supplied with water, cut Christmas trees generally consume about 1 qt (about 1 L) of water per day per inch (2.54 cm) of stem diameter. Thus, a tree with a 4-in diameter trunk would use about 4 qt (about 4 L) of water per day. The biggest mistake by consumers is using a stand with too little capacity, resulting in trees drying up between waterings. If this happens, the tree might not rehydrate when rewatered. (Hinesley, L. E. and G. A. Chastagner, 2016)