How Plants Survive The Cold (Or Not)

frosty_leaves.jpgPlants Can’t Come In From The Cold

Imagine for a moment that you had to stand outside your house or apartment, without moving, all winter long…and that you were naked.

How long do you think you could last?

Not long, especially if the temperature went below freezing. And certainly not if the temperature went below 0o F (-18o C).

In temperate zones on Earth that’s what perennial plants must be able to do to survive.

And even annual plants may have to withstand an early or late frost in order to complete their life cycles.

But, you may reply, plants are not warm-blooded organisms like mammals. What difference is it to them whether it’s cold or not?

How Cold Kills Plants

What happens if water freezes inside at plant?

At least a couple of things can happen…both bad for the plant.

The first, and likely lethal for the plant, is ice crystal formation inside cells. This has just about the same effect on a plant cell as the little alien chestburster did on the actor John Hurt in the movie Alien. (Sorry, but it’s an effective analogy.) It’s lethal.

If, however, the water freezes outside the cells, in the intercellular spaces, this may lead to the extreme desiccation of the plant. That is, it’s sort of the same as if the plant was drying out.

Other cold-temperature effects on plants include (1) decrease in enzyme activity and (2) changes in the fluidity of cellular membranes, both of which could severely harm plant cells, and, thus, the plant as a whole.

How Do Plants Cope With the Cold?frosty_tree.jpg

To answer this question we have to consider plants at the cellular level.

How do the cells of cold-tolerant plants survive sub-freezing temperatures, i.e., withstand dehydration and, more importantly at very low temperatures (below 0o F or -18o C) , avoid the formation of ice crystals in the cell?

1. Accumulation of solutes (sucrose, mainly, but also other organic compounds such as proline) by the cells to depress the freezing point of water (think salting ice on the sidewalk) and to stabilize membranes. (But this can only be effective at temperatures from 32o F to 20o F.)

2. So-called “antifreeze” proteins help prevent ice crystals from forming in the extracellular spaces (outside cell); plant cells that make these proteins typically secrete them into cell wall region (intercellular spaces).

3. The plant cells may synthesize proteins called “dehydrins”, which are inside the cell (cytoplasm), may bind water molecules and alter the collective structure of water in the cell to stabilize membranes.

4. Plant cells can alter lipid composition of cellular membranes in order to adjust the fluidity (functionality) to colder temperatures.

red_leaf.jpgCan Plants Generate Their Own Heat?

A silly question? I think not.

Some unusual plants, by partially uncoupling their cellular mitochondria, can generate small amounts of heat. (Please see ref #1 below for more information) But this is likely not very significant with regard to cold tolerance, however. (More on this interesting topic here.)

Bottom Line: Plant cells survive sub-freezing temperatures by adjusting their solutes, proteins, and membrane lipids in order to withstand desiccation and to avoid ice crystal formation.


1. Seymour, Roger S. (1997) “Plants That Warm Themselves.” Scientific American, March 1997, pp. 104-109. (Full Text – PDF)

“Out in the Cold” – Tom Petty and the Heartbreakers

HowPlantsWork © 2008-2011 All Rights Reserved.


  1. Do plants hibernate in the winter please give me a answer with evidence.

    • Yes, in a way, they do. It’s not called hibernation, it’s called “dormancy”.
      For more on this, scroll to the top of this page, and type “dormancy” into the Google search box for this website, and click on Google Search. This will open a new page showing search results, topped by a link to see how plants “chill out”.
      Good luck, and thanks for your question.

  2. hey i just am doing science fair for my school so i used this site for info. So i wasn’t sure is it true like 100% true that plants could survive the winter weather?
    thank you.

  3. Thank u sooo much

  4. How cold are they keeping my classroom at night if my plants are dying? Any way to know? Poinsetta, Peacy Lily

    • Being sub-tropical plants, poinsettias may wither at temps below 50 F, which is pretty chilly for indoor temperatures, even at night.

      One can purchase a temp/humidity monitor (AcuRite 00613 Indoor Humidity Monitor) at Amazon for about $11 that records daily hi/lo temps – – to satisfy your curiosity re. your overnight classroom temps.

  5. Would injecting plants with sucrose or proline help them survive better in the cold? This is in reference to normally warm weather plants and it is for a science experiment.

    • Would injecting warm-weather plants with sucrose or proline help them survive the cold?

      Maybe this would be effective only in very small (thumb-sized) plants. For larger plants, I think it would be difficult to inject enough of these “anti-freeze” substance to be effective.

      Also, for these substances to work optimally, they really should be delivered inside the plant cells. Unless the plant cells were able to take up relatively large amounts of sucrose and proline from outside the cells, injecting them into the plant itself probably wouldn’t work. And it would also take lots of cellular energy (ATP) to transport these substances across the cells’ cellular membranes into the cells.

      As you can probably imagine, it’s pretty difficult to effectively inject stuff into plants. Plants don’t really have a circulatory system like animals. Although plants do you have transport systems called the xylem and phloem, it would be pretty tough for you to physically inject material directly into these systems.

      You might be able to increase the sucrose and proline levels in the plants by watering them with relatively dilute solutions of these substances. You have to be careful, however, because if your solutions are too strong, they’ll osmotically draw water out of the plants.

      You may want to think about the idea of somehow inducing the plants to accumulate these substances naturally. How so? For example, many plants respond to water stress (drying out) by accumulating sucrose, proline, or both. So, I wonder if your plants would be more cold tolerant if you first subjected them to several days of drying out.

      It would really help if you had the ability to measure relative amounts of sucrose and proline in your plants, by sampling leaf tissue for example.

      Anyway I have rambled on way too long. Good luck with your experiments.

      • Hey you probably won’t answer because it’s 2019 (4 years since you’ve even said this), but I am doing a biomimicry project and I’m trying to figure out how plants could survive the cold longer. Do you think it’s possible to have a fertilizer of some sort or sucrose or proline at the central part of the plant, where the plant could naturally grab as much as it needed to help it survive the cold? Or is this me coming up with some impossible immature solution?

        • Adding such organic compounds such as sucrose or proline is impractical for several reasons, such as creating osmotic issues and metabolism by bacteria and fungi. To prevent crop damage from unseasonal freezing episodes, cranberry and citrus farmers, for example, will spray water on the crops because when water freezes it actually releases heat. This may be enough to protect the plants from sub-freezing temperatures.
          For your biomimicry project I would suggest you investigate so-called “antifreeze” proteins, particularly in plant-associated bacteria. Also, there has been interest in genetically-engineered ice-nucleating bacteria, especially with regard to strawberry crops.

          • Wow! First off, thanks so much for replying, especially so fast, and second, your page is amazing and has helped me a lot for this project. Third, that is a great idea and I will research ice-nucleating bacteria. Also, I know you already said this is impractical, but what if the soil had some of these proteins and solutes in it? Could the plants take in these solutes and proteins and allow themselves to survive better in the cold? Thanks again!

          • Most plant roots contain a barrier called the Casparian strip that would likely prevent what you suggest. (Google it.) However, it may be possible, but highly unlikely, for plants to take in the compounds you mention, as long as there were specific plant cell membrane transporters for these substances. Moreover, the plant would have to expend energy (ATP) to take up these compounds, they wouldn’t simply diffuse into plant cells (see Casparian strip and cell membranes as effective barriers to such solutes).
            But, as I previously mentioned, in natural environments, the soil microbes would quickly metabolize (eat) such compounds long before the plants could take them in, even if they could. In artificial conditions (think sterile hydroponic greenhouse agriculture), you might get away with it. But, of course, under such a scenario, one wouldn’t have to worry about freezing in the first place.
            You’ve chosen one of the more challenging questions, historically, in plant science as it relates to agricultural production. Scientists have worked on ways to enhance plant cold hardiness for many years (decades), with not a whole lot of success, outside of plant breeding. Genetically breeding new varieties of cold-tolerant crops (typically from cold-hardy native relatives) has been the most successful route, to date. But plant genetic engineering (especially CRISPR) provides a way to genetically transfer cold-tolerance mechanisms (antifreeze proteins, e.g.) across the species barriers (from antarctic fishes to plants?). In other words, it’s now possible to engineer plants to mimic (is “biomimic” a word?) cold-tolerance strategies from the complete span of Earth’s (even alien – life on Europa?) life forms – from bacteria to mammals. (As Yoda might say, “Exciting times are these!”)

          • Okay, thank you so much! You’ve been a great help! I might ask more questions later but for now, I am going to research the ice-nucleating bacteria (aka ice-minus bacteria) and also research about how some different species could help plants in the cold.
            Thanks again!

      • Hey! I’m back again! You have been such a great help! I am almost done with my biomimicry project and have found out extremely interesting facts about ice-minus bacteria and other ways plants could survive the cold. I might send you everything I’ve learned once I’m done. But, I have one more question: Is it possible to inject too much proline and sucrose? Can plants get clogged up with a substance?
        Thanks soooo much!

        • Hi, again,
          Welcome back….
          Have you ever donated blood? I have. (I’m O negative, so the Red Cross loves it when I show up.) To do so, they need to tap into a vein. The opposite is an “intravenous”, abbreviated “IV”, (“within vein”) injection e.g., injections of medications (or, sadly, addictive drugs, such as heroin). Conversely, N.B. (Nota Bene), when you get a vaccination, the injection only needs to be “intramuscular”, so as to allow for the vaccine to slowly diffuse into your bloodstream to elicit an immune response. (Believe it, or not, all this has relevance to your question.)
          Anyway, injecting stuff into plants is highly problematic. Do you want to “hit a vein” or not? If the former, then how does one find “veins” in a plant?
          As you probably already know, plants have a vascular system (veins) consisting of the so-called “phloem” and “xylem”. The former primarily carries sugar from the leaves to the roots, and the latter primarily carries water from the roots to the leaves. (This is a gross oversimplification of their functions, but you can get the full picture by Googling these two terms online.)
          Although I know how one can specifically tap into the phloem (hint: aphids), in general, it’s tough to inject stuff directly into a plant’s vascular system. So, one is typically stuck with just injecting stuff (whatever it may be) into the “intramuscular” equivalent in plants, typically the stem tissue. Because plants consist of walled cells (think bricks in a wall), unlike animal tissues, there is lots of intercellular space in plant tissues (analogous to mortar around the bricks). This extracellular space is, typically, porous, that is, water can flow around and between the cells.
          Thus, when you inject proline or sucrose, as you propose, there is likely a low probability that “clogging” would occur.
          How’s that for an extremely roundabout way to answer your question?

          • Haha that is a very interesting answer! Thanks so much! I will keep you updated once I finish the project, which will either be tonight or tomorrow. Thanks again!

  6. I grow trees in central Alberta. Here our winters can get to -40 although usually at that point we have about a foot of snow on the ground.

    I have been growing my trees in pots. Everything I’ve read says that I should kill most of my trees every year. A #2 pot (roughly 8″ across x 9 tall) should allow the roots to freeze solid. While I’ve found that growth is not as swift as I would like, I run under 3% mortality per winter.

    That said: I’ve notice that mortality is concentrated on the NW corner of a block — the direction that our bitter winds come from. How much of adaptation to severe cold is not “how cold it gets” but “how fast it gets cold”

    • Great question.
      The development of tree cold hardiness is a complex process that certainly takes time, sometimes weeks to months. So, a brief answer to your question is: Yes, how FAST it gets cold is certainly an important factor.
      I’m no expert on tree cold hardiness, but I know that the induction of cellular cold hardiness in plants is typically triggered by both the photoperiod (think longer nights) and low temperatures. In perennial trees such as yours, in general, the living tree cells first change – membrane lipids, solute accumulation, “anti-freeze” proteins – to become more cold tolerant. Next they enter the next stage, namely, dormancy, which is more complex and more poorly understood. It’s this deep winter dormancy that likely what allows trees to survive extremely low temperatures.
      I lived in Bozeman, Montana for over 20 years. And during this time there were several Novembers in which temperatures rapidly (one day) plummeted 60 to 70 degrees F to wind up 15 to 25 below zero F. I wasn’t the only one who noticed that many mature trees around town (especially beech) were obviously dead the following spring. I presumed that this was due to the rapid onset of extreme low temps the previous fall.

  7. so im doing this science project which is which plant would die quicker in a freezer or a cabnet pls help me

  8. I am have a small courtyard, what kind of tree, or shrub will survive outdoors, in a pot, during the winter in Denver??

    • Susanna,

      I would not be so presumptuous as to provide you advice re. your excellent question.

      Please allow me to refer you to your local Colorado State University Ag Extension in Denver:

      888 E. Iliff Avenue, Denver, CO 80210
      (720) 913-5270

      My experience has been that such offices offer a wealth of practical and reliable information.

      And, besides, your tax dollars are helping to pay for these services, so your are certainly entitled to access their expertise.

      Good luck!

  9. Well I’m please to have read in your cited post that day length can drive some winter dormancy because here in the UK the seasons were going ‘as normal’ and then suddenly have plumeted from average. I thought the speed of onset of the freeze may have done for some of my plants that had not got ready for winter because of the experienced temperatures.

    I also try and dry down pots as I’ve always thought this too increases winter survival but also plays to your final line…that is to better manage when plants really get going during spring. Interesting that drying down and winter dormancy are similar for the plant too (Cited article).

    The whole thing is made more complicated though by having plants in pots. Eg I have bulb in a large pot and planted IRO 6inch deep. If that bulb was in the ground it would take heavy frosts to penetrate that far down into the earth. However in the pot 2 inches of frost will be knocking on the bulb’s door so-to-speak, accessed easily enough through the side of the pot. So a ‘dangerous minus 17 degrees’ becomes a ‘dangerous minus 6 degrees’ or whatever.

    Anyway after posting to you though I realised I could compartmentalise a lot more than a few pots in storage boxes. I made a large bench put my most precious pots on it, covered it with fleece and bubble wrap overhanging the edges of the bench by a good amount and put a low burning twin flue heater beneath. So I’m heating up a compartment where prettymuch all the heat is contained in a fleece/bubble wrap tent. I decided I could aim for a ‘slightly frozen’ minus 2 to 4 degrees minimum (ie frosty but not deeply penetrating).Tried it live last night and it shows the capacity to keep at plus 2 degrees in a minus 4 degrees night…so plenty of wiggle room for using numbers of burners, burner settings, varying insulating layers to keep the minimums around minus 4.
    The setup seems so fuel efficient I may even get away with using a very small heater even on a minus 8 night. LOL well all intersting to me:)

  10. Thanks for the reply.

    Afraid I don’t have spare plants to experiment with to find the answer to this.

    And the greenhouse is pretty full so I can’t accomodate large bodies of water to explot the specific heat capacity and latent heat of freezing of water. And at this time of year generally the bottom of the greenhouse (where I’d have the water containers) gets no direct sunlight at all.

    I have a heater but its not large enough to keep a 10×8 greenhouse from very cold temps (NW UK, Europe) and I don’t think I could afford to. The best I could do would be to be compartmentalise the most valuable pots into containers with reused 4 pint milk bottles , a covering of multipurpose compost and a bit of fleece.

    But that doesn’t answer the question of what’s best for plant survival one deep freezing period or many cycles.

    • Indeed, I didn’t answer your question.
      That’s because it depends…….on what plant species are in your pots.
      Plants vary greatly with regard to their ability to adapt to cold (or not). Some woody perennial plants enter a “resting phase” or endodormancy to over-winter. Other plant species may transition in and out of cold acclimation in a matter of days, depending on the temperatures. This post may help a bit: .
      I wish that I could provide a simple answer, but it’s a complex subject. If I had to choose one or the other, one deep freeze or cycles, I’d be inclined to go with the deep freeze. This would be to try to avoid the chance that the plants lose their cold tolerance during a warm period and then be hit with a subsequent killing freeze.

  11. Good article.

    This year I have a greenhouse and I am wondering about implication of not just frost but also of frost free periods.

    If a pot has frozen to say -2degrees centigrade overnight is it a good idea to let the greenhouse heat up to defrost the pot during the day (eg leaving all windows closed during sunny day) or is it better to leave the pot in its frozen state? Or in other words is it better for a pot to be frozen for 2 months or frozen and thawed and refroze over and over for 2 months? I could almost see getting re-frozen over and over as more damaging than one protracted freeze.

    • It would be a shame to open the greenhouse windows during the winter. But I appreciate your concern regarding repeated freeze/thaw, although the cells of cold-hardy plants wouldn’t likely be frozen by -2 C. Of course, a simple experiment might be to move some pots outside and compare them to those left inside the closed greenhouse.
      I’ve used passive heat sources to warm small greenhouse overnight by painting several 5-gallon water jugs black, then filling them with water and placing them in a central location in the greenhouse that gets sunlight. They warm up during the day, then slowly radiate the heat overnight. Not a great heat source but may help on nights that dip slightly below freezing.


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