17 degrees? coping with spring frost in a garden

IAM NOT EVEN SURE WHAT TO SAY ABOUT THIS: Weather that in less than a week goes from near 80 to more like 18 (other estimates say 17, even, for tonight, with winds up to 40 miles per hour as the icing on the ice-cream cake). In March. A March that looks more like late April, or maybe May. I dared last week to pot up giant bowls of pansies and violas, all of which are now taking shelter under upturned wheelbarrows and garden carts, like the one above. What else is there to do about a hard freeze that’s threatening a big swath of the northern and eastern section of the nation?

Watering the soil in pots–or beds–well before tucking things in is the first line of defense here, and what I did this afternoon. Cornell says that moist soil can hold four times more heat than dry, and also conducts the warmth toward the surface faster to aid in frost prevention.

Watering the actual plants–such as with a sprinkler or hose-end wand–to wash off the frost just before dawn (the coldest part of the night)–can help when temperatures will be just around freezing, but with 17F forecast, I’m not setting any wakeup alarms here. Useless.

I’d rather turn large containers and boxes (or my carts) upside-down over things than lay material right on top of succulent, tender plants–especially when high winds are forecast that will whip the material around. When I do need to resort to a fabric covering, like the side-by-side whiskey barrels of pansies above, I avoid stiff plastic or paper in favor of cloth (such as the a frost blanket made of Agribon 50).

Either way, I weigh down my protectors–even my wheelbarrow, on a night like tonight is meant to be has a rock on top of it (top photo). Pillow cases can come in handy, since you can slip them over certain things. Whatever covering you use–and it’s better if it doesn’t weigh on the plants themselves, of course–it must go on before the deep cold begins, and must come off before the sun warms things up the following day. In my case, with 20s forecast Tuesday night as well, I’ll be recovering things tomorrow.

The scariest part is loss of tree buds on one-chance-per-year fruit-producing crops like stone and pome fruits, some of which are showing color nearby (and others are already open because of last week’s record warmth). The University of Illinois Extension says a fully open apple blossom, for instance, can withstand temperatures of about 28 degrees F, with substantial injury at 25 degrees and lower.

Pray for clouds tonight, which help keep warmth from the earth down nearer to its surface than a clear sky!

more on frost

  1. Jen says:

    I used frost blankets to wrap my small pear trees- I’m pretty sure it’s not going to get as cold as it will by you tonight- and I do have to work tomorrow- would it be bad to leave them covered tomorrow? They are about to bloom. Also covered my lettuce, garlic, and clematis that’s taking off. This weather stinks. :(

    1. margaret says:

      Hi, Teri. The last part makes total sense to me…why did I forget to list that to-do in the article? :)

      Hi , Bob. Clear is bad; clouds are better insulation! What a weird stretch of weather — since last fall, right? See you soon!

  2. Mary says:

    Good luck. I hope you have lots of clouds and the temps don’t dip into the teens, so you don’t take big losses with your plants and fruit trees. It feels like May in Texas. It’s unbelievably warm down here with no cold front in sight.

  3. Bob says:

    We’re forecasted at 22 and clear. After last week’s heat everything’s surging, peonies are budding, the magnolia’s in full bloom. The garden’s now dotted with upturned buckets and styrofoam coolers. Thanks for the tips!

  4. Lizzy says:

    Hi Margaret!

    Do you think I need to protect the roses that ll have leafed out? We are in upstate NY (about 2 hours from you) and almost everything is awake – leaves on crabapple trees, purple leaf plum is in full flower with leaves as well, the roses and many other shrubs have leafed out, etc. I am definitely going to cover my Japanese Maple, but what else is a top priority?

    1. margaret says:

      Hard to say, Lizzy. I agree the Japanese maples are very vulnerable. Not sure re: new rose foliage. Getting down into the mid-30s here now so not really much more time to do the protecting…

  5. Terri H. says:

    Oh, dear. I hope it’s not as bad as the forecast.
    Here in N. Illinois we are only dipping into the upper 30s.

  6. Terryk says:

    Lots of luck to all of us. Do you think it might kill some of the weeds that are starting to grow too? That would be the only good thing about this plunge in temperatures!

  7. Diana says:

    I was running around the garden like a crazy woman covering things up today. How silly and delusional was I to unwrap the brown turkey fig tree last week? New neighbors just moved in today and must be a little unnerved, what with the odd assortment of upturned garbage cans, storage containers, and black garbage bags littering the yard (and protecting the flowering blueberry, honeyberry plants and pansies etc etc…).

    1. margaret says:

      Hi, Diana. Yes, “welcome to the neighborhood” right? Hilarious. Love the image of them looking out at your concoctions.

      Hi, Leo. Wow, crazy. That’s some change. Wish we’d get some rain/snow/something wet in the midst of this havoc. But dry, dry, dry. UGH.

  8. Martha says:

    Hi. I just recently found your wonderful, resource of a website. Thank you for all the information! I am a beginner gardener–I’ve tried many things without a lot of luck (I’ve been living in the very difficult climate of Stockholm, Sweden for seven years). Now we are in Greenwich, CT, however and I expect my luck to change!:-) Our property has a lot of large rock underneath without much topsoil and fairly bad drainage. We will likely fix the main area of the lawn in the coming years, but no plans to do much to the perimeter, which is mostly higher ground. Some evergreens that have provided privacy in the past have died off (we bought the house last summer and I am fairly certain they died because of shallow soil and over planting/crowding) and I now have holes along our deer fence, with some, as of yet, unidentified shrubs. I was thinking of putting in some pussy willows, and have emailed with Michael Dodge about it, but I’m worried about them becoming invasive. The areas I need to cover are on the north and east side of our property with some large trees beside–so some sun, but not full. Do you have any advice for such a place?

    1. margaret says:

      Hi, Martha. Many of the pussy willows simply get tall if left unpruned — like small trees — but don’t sucker. On the story about them in the comments you will find some details on that. Here. Sounds like a shady-ish spot that you have though…would woodland edge things be better, maybe?

  9. Deborah Banks says:

    It was 14 degrees here when we got up this morning. I was amazed that we didn’t see a layer of white frost on anything. Super cold but the grass was still green and the daffodils looked perky. Later after the sun was out, the daffodils wilted to the ground and things like the new growth on sedums looks bad, but mostly everything is not as bad as I expected. My husband said the dewpoint determines whether you actually get a white layer of frost or not, and that we didn’t get it because it’s dry. I googled and read some info that said the opposite; high moisture can prevent the frost layer. Can you help explain why no frost at 14 degrees?

  10. Kerry says:


    If the night was windy, frost will not form because it is difficult for moisture to settle down onto the plant surface. However, the air temperature is below 32F, so you will have what is called an air frost, which can still cause damage to plants.


  11. Kerry says:

    Forgot to mention that the air was also extremely dry and the dewpoint was low which also inhibits frost formation.

  12. Deborah Banks says:

    The wind died down during the night, but you’re right that the air was dry and the dewpoint was very low. Kathy at ColdClimateGardening posted about it yesterday. In terms of how it went, I had damage to young foliage on some emerging perennials like certain hardy geraniums and daylilies, none whatsoever on tough bulbs like chinodoxia, scilla and hyacinths. Worst for me was that my magnolia ‘Ann’ lost a lot of buds, even though they weren’t very advanced and I had her wrapped in row cover and a polartec dog blanket. My tougher Dr Merrill magnolia just lost the buds already opening; the others look fine.

  13. Linda says:

    Well, now we know what will survive 17 degrees after two weeks in the 70s. The star magnolia flowers are sad brown things but obviously the tree survives to try again next year. The brunnera, which had started to leaf out and form flowers, are very unhappy but the roots survive to leaf out again. I did not run around trying to cover much up- this is likely the turbulent weather of our gardening futures and natural selection (with the help of the judicious choices of the gardener) will decide what my gardens are to look like going forward.

    1. margaret says:

      Here, too, Linda — some of the perennials that had begun to flush are a brown mess but will start again! Fingers crossed, right?

  14. Laurel Sears says:

    I’m in Kansas and to further emphasize the weirdness of the whole (non)winter and extremely early spring- It’s basically May here. Lilacs, pears, apples, plums and crabapples in full bloom. Magnolias are all done and leafed out. Lilacs are in full fluff and bulbs are nearly done. WE HAVE IRISES. Seriously, it’s hasn’t frosted here in 6 weeks. It is ridiculous. Beautiful. Ridiculous. Nervous-making.

  15. Rachel B. F. says:

    Best of luck Margaret! Northern New Jersey Magnolia x soulangeanas took a pretty visible hit, but most other flowering trees, shrubs, and bulbs seem to have made it through. More chancy weather in the near future though!

  16. Liv says:

    So should I be covering up my lilacs, hydrangeas and day lilies? We had 25 degree Celsius weather last week and this week it is 8 Celsius with it hovering around freezing at night. One night we had minus 10 and freezing drizzle so I covered everything up with garbage bags. Am I doing more harm than good? (Sorry I don’t know what the temps are in Fahrenheit!)

  17. Gayla Templeton says:

    Every gardener understands that sick sorrow to know you have lost a tree crop and also ground crops if the cold comes later. I’m so sorry you are dealing with that. Here in KS it has not been the cold but the heat that has burned the blooms on the bulb plants after only showing for a couple of days. I had to be away the day the 85 degree 40 mph wind kicked up and by the time I got home everything was fried crisp.So be it cold or unseasonable heat this is not a happy year for flower lovers. Another thing that has just burned me to a crisp is turning on the air conditioner in March. After flipping and flopping aorund in bed for an hour I gave up and turned it on. Not sleeping because the house is too hot in March is a first and I’ve been here for 67 years. I keep replayingin my mind all my parents stories about the dirty thirties and the early heat seems to be what I remember them talking about. We are getting plenty of rain though so I’ll try not to worry about what is not here yet. Raising children or plants is destined to break your heart from time to time and this year seems to be leaning that direction.

    1. margaret says:

      You are welcome, Peaceful Valley. Time to do a story together soon, no? Need to share in your expertise! Will be in touch — or find me at awaytogarden at gmail. : )

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.