Hoar Frost - You Ask We Answer

Crystallised Eryngium - 7th December 2008, in my garden

In my Comments on Monday Gail asked:

Is this the famous English hoarfrost we have all read about! PS Our high school song spoke of the hoary walls and we all laughed in teenage ignorance!

I was just going to give a quick answer in my comments, but what better topic is there for You Ask We Answer than the great British weather? So the YAWA staff here sprang into action immediately to find out.

The word hoar comes from the Middle English hor, which in turn comes from the Old English har. It's related to Old High German, which makes me wonder if there's a connection to the German word haar (hair), which we're singing about in Silent Night at choir at the moment. Hoar itself has two meanings: the first is ancient, such as a hoary beard, which means one whitened with age, just like NAH's! The second is white, thus giving us the descriptive white frost, sometimes used instead of hoar.

The BBC Weather Pages says hoar frost forms when the air cools so that water condenses out of the air onto garden surfaces such as grass, plants, or as my photos showed on Monday, sheds and fences. This is quite different to frozen dew which looks like frozen water droplets, whereas hoar frost has a delicate, ice crystal structure. According to WeatherOnline, the objects the water condenses onto must also be below freezing and the resultant hoar frost looks like needles, feathers and spines. It also suggests that the air must be supersaturated with water i.e. above 100% humidity for this effect to take place. Hoar frost shouldn't be confused with rime, which forms from freezing fog, or glaze which forms as a continuous sheet of ice. Unlike hoar frost, both aren't formed from individual frozen droplets.

The BBC website gives two further definitions: Air frost is when the air temperature reaches zero degrees centigrade (32 degrees Fahrenheit), though the ground can sometimes stay above freezing. This often happens in early autumn, as the soil still retains some of its summer heat. Ground frost is when the ground's surface temperature reaches zero. This can happen even though the air temperature may remain above, at say 3 or 4 degrees centigrade.

On very special days hoar frost gives us that 'winter wonderland' effect, which when combined with sunshine can be magical - as shown in this magnificent photograph. There's also an apple called Hoary Morning, originating from Somerset in 1819. Its skin has a deep bloom like hoar frost, hence the name.

So Gail, I suppose the short answer to your question is yes, my photos did show hoar frost, but I hope you've enjoyed my longer explanation and a further picture from Sunday. Now, how did your hoary high school song go? ;)

Comments

  1. TYRA Hallsénius Lindhe11 December 2008 at 09:27

    Hello VP and thank you for today's YAWA lesson! You are a good tutor no no wrong you are an excellent tutor...:-)

    LOL Tyra

    New Post from Tyra - Leufstabruk

    ReplyDelete
  2. Sylvia (England)11 December 2008 at 12:19

    We have had several hoar frosts already this year in Dorset. We have been having some mild winters with hardly any frost at all but last year we had a few frosts and this year is looking very cold. It was -5C this morning and out of the sun is still below freezing here.

    Lets hope it will kill a lot of the newer bugs we have been getting - now if it killed the lily beetle I would be very happy, worth getting cold for!

    Best wishes Sylvia

    ReplyDelete
  3. dianasfaria.com11 December 2008 at 13:59

    I like the textures in this photo very much. Yesterday's photo was pretty neat too. I'm glad you posted about being undecided. As a new writer myself, it was very informative reading everyones responses. Good luck with your decision.

    ReplyDelete
  4. emmat11 December 2008 at 14:10

    do we have to pay $49.99 to read this informative post?

    ReplyDelete
  5. Mrs Mac11 December 2008 at 14:18

    Ahhh thank you! I love etymology! Here so far we've only had ground frost so my tall, dark burgundy chrysanthemums are still blooming!!! LAst year they lasted till a few days before Xmas! They're not really an outside flower, bought in a pot for display indoors only. This means they are partial to bad rusts. Every year I spray them but every year I end up taking off lots of affected leaves, leaving just a few good ones. It is tiresome. But this time of year I see them, the only flowers around abouts, and it is so worth the effort!!!

    ReplyDelete
  6. Gail11 December 2008 at 14:58

    VP,

    Thank you for the answer to my question! Hoar frost is beautiful and I don't believe we have it very often here...or I am not quick enough to notice it. Now I shall be on the lookout! More reasons to have that new camera!

    To answer your question...only one line comes to mind and a search of my yearbooks (yes I still have them!) reveals nothing! I will continue to search for it! But it is something like 'The hoary walls of Normandy...' We had many old brick buildings!

    The love link is much appreciated!

    Gail

    ReplyDelete
  7. Cindy, MCOK11 December 2008 at 14:59

    I'll never get to see hoar frost here on my corner of Katy so I'm very much enjoying your pictures, and the explanation of this meteorological phenomenon. Thanks, VP!

    ReplyDelete
  8. Anonymous11 December 2008 at 15:57

    That was very interesting - next time it's frosty I'm going to pop outside and see if it's hoar frost or frozen dew. A more intellectual reason than usual for getting the camera out (lol)

    ReplyDelete
  9. Anonymous11 December 2008 at 16:04

    Very informative! We have hoar frosts here occasionally (http://nancybond.wordpress.com/2008/01/31/frosty-mist/) and they're so beautiful, especially with the sun on them. Thanks for the info!

    ReplyDelete
  10. Anonymous11 December 2008 at 16:48

    Very cool...I had never hear of hoar frost before. Always come away from here just little smarter!!!

    ReplyDelete
  11. tina11 December 2008 at 23:13

    I enjoyed it very much! That tree in the photograph is magnificent. It looks like snow.

    ReplyDelete
  12. Amy12 December 2008 at 02:06

    What a great post! We woke to a hoary winter wonderland this morning :) I threw on some pants, a hat, and a jacket over my pajama top and got some pictures while the light was good. I wonder what the neighbors think sometimes...

    Amy

    ReplyDelete
  13. Philip Bewley12 December 2008 at 18:38

    I just loved learning more about this!
    I will look for this in the High Sierras.
    I enjoyed the word origins you provided, too.
    Best regards,
    Philip

    ReplyDelete
  14. Mr. McGregor's Daughter12 December 2008 at 23:42

    Thanks for the info! At least it explains the "hoar" part of my favorite common plant name, Hoary Puccoon. Now if I can just find out what a "puccon" is...

    ReplyDelete
  15. VP13 December 2008 at 13:08

    Hi everyone - glad you enjoyed the explanation, especially Gail who asked the question in the first place. I've several of these in mind under the You Ask We Answer umbrella ;)

    Like Sylvia I'm hoping our hard frost will kill off all the bugs, particularly the Horse chestnut leaf miner I wrote about earlier in the year.

    Emma - what do you think? Did you pay to read it? Did Tyra, Inadvertant Farmer or anyone else for that matter? ;)

    Lily Hydrangea - welcome! Thnaks for stopping by :)

    Cindy - I think you don't get them because the States winter air is drier than ours? I've added a little note about it ready for GBBD on Monday.

    Helena, Philip and MMD - I love word origins too. It was good to go and do a little research and I've been waiting for an excuse to write about the Hoary Morning apple as it's one of my favourite names.

    Nancy - your frosty mist was lovely :)

    EG and Blossom - it's always great to have an excuse to go out with the camera and who cares what the neighbours think? :)

    ReplyDelete
  16. VP14 December 2008 at 17:14

    Cindy - ah silly me, you're probably too warm a climate down your way to get them aren't you? I've cancelled my little bit for tomorrow's GBBD.

    Good to see you here :)

    ReplyDelete
  17. Monica the Garden Faerie28 December 2008 at 22:06

    Thanks for the info on hoar frost. Aren't Eryngium grand? Some snow-capped ones in November at my friend's house are here.
    ~ Monica

    ReplyDelete
  18. VP6 February 2009 at 20:40

    Garden Faerie - Bananas! they're fantastic!

    ReplyDelete

Post a Comment

I love hearing from you and welcome thoughtful conversations :)

Comments aiming to link back and give credence to commercial websites will be composted!

Your essential reads

That blue flower: A spring spotter's guide

Image
Spring is a prime time for blue flowers and my daily walks currently have several from the same plant family* lining the local footpaths. As I walked past the Donkey Field the other day, I overheard some children ask their parents** what the pictured blue flower was. It reminded me it's often mistaken for those other familial blues and this time was no different, as they said it was forget-me-not, instead of the green alkanet it actually is. As well as similar flowers, most of these plants are hairy in their nature, flower around the same time, and favour damp, shady places. Many of them are great for pollinators too, especially bees and this week's warm weather has certainly drawn them to these flowers. This makes it even more likely for these plants to be mistaken for each other and it's a great opportunity for me to put together a spotter's guide in case you find the same flowers on your outings. Staying with green alkanet, the key features which set it
Read more

Jack Go To Bed At Noon

Image
Last year this rather exotic looking flower appeared on mine and several other allotments for the first time. Having been stumped (again) by Mr Allotment Warden as to its identity, I rushed home to find out what it was. It's salsify, aka the marvellous Jack Go To Bed At Noon - named as such because its flowers always close by midday. Here you can see both open and closed flowers - making it seem even more exotic and alien than in the first picture. I think this must be the cultivated version because the flower in my Francis Rose Wild Flower Key looks exactly the same in form, but is bright yellow in colour and called meadow salsify . Its other common name is Goatsbeard, which must be a nod to the fantastic dandelion-like clock which forms the seed head. With 'parachutes' like those shown above, who knows how far our plotted plants came from. I rather like the photographic dissection of the seedhead found in this link . Salsify is edible: its lateral shoots and fl
Read more

Red Nose Day - Gardening Jokes Anyone?

Image
The nation goes ever so slightly bonkers on Red Nose Day - hurrah! Previously, it's been very easy to join in - usually via a dress down day at work plus lots of people up to mad things at the station and in the office. Everyone smiling for once - it's a real feel good day and all in a good cause. This year's different - every day's a dress down day for me now - my friend L suggested yesterday that perhaps I could have a dress up day instead and whilst that's a good idea, I confess that ballgowns and tiaras don't really feature in my wardrobe: scruffy student's always been my favourite look. So my Red Nose Day contribution for this year is to compile a list of gardening related jokes. For each one (clean ones only please) you leave in the comments below, I'll make a donation of 50p to the cause. Here's a few for starters just to get you warmed up: Q Why do potatoes make good detectives? A Because they keep their eyes peeled. Q What did the grape
Read more

Salad Days: Mastering Lettuce

Image
I've decided one of my salad challenges for this year is to grow as many lettuce varieties as I can, ready for the publication of my planned Factsheet* later on. The idea is to grow as many of the Tried and Trusted lettuce varieties last year's Salad Challengers helped compile, then provide a visual guide and as many lettuce facts as I can muster. So far I've found around half of those listed**. Then naturally whilst I was out searching - because such is the way with seeds - a number of other varieties found their way home too ;) A couple of weeks ago I sowed 22 varieties***. Just the simple act of sowing them has me intrigued. Why are some lettuce seeds black and others white****? They split into about half white to half black in my sample and as far as I can tell it's nothing to do with whether they're a type of cos, iceberg, or whatever. I sowed them indoors and popped them into a propagator on the windowsill. The soil's too cold outside for sowing
Read more

VPs VIPs: Derry Watkins of Special Plants

Image
Last week I had the pleasure of visiting Derry Watkins at her home, garden and nursery - the acclaimed Special Plants - just a few miles along the road from me. I first met Derry at one of her open garden days last year and was keen to find out more about her wonderful garden and running an independent nursery. She specialises in tender perennials and regularly goes on plant hunting trips to find new treasures, particularly in South Africa. As well as running Special Plants and opening her garden under the NGS scheme , Derry holds day courses at her nursery, hosts Special Tuesdays from April until September, lectures and has written a couple of books. How did you find your way from Connecticut to the UK? I'd started a biodynamic vegetable garden in Connecticut and we used to have people come along at weekends to help out. A particular young man turned up: he returned many times and at the end of the summer I married him. So it was all down to love? Isn't that the
Read more

#mygardenrightnow: heading into summer with the Chelsea Fringe

Image
Ahhhhhh, that's better! I love walking through dewy grass in bare feet, not that there's much in the way of grass on my back lawn this weekend. My wild and woolly lawn has morphed into meadow of sorts this month, which even NAH admits looks attractive*. It's also proved a great source for my Flowers for mum project so far, yielding self-sown perennial cornflowers, lamb's ears, and lemon balm in addition to the blooms you can see. These originated from elsewhere in the garden, the ox-eye daisies must have blown in from the A350 nearby. * = he got very stroppy about the weeds aka self-sown foxgloves in the lawn one year, so he's come along a bit since then. Skimble's demanding to say hello to you too. He does enjoy the patio when it warms up. If the embedded video doesn't work try this link instead. The Nectaroscordum are a revelation. I planted the bulbs around 2 years ago, but it's only this year they've bloomed properly. The bee
Read more

The Resilient Garden

Image
  Part of Tom Massey's Resilient Garden at RHS Hampton Court I've been pondering VP Gardens a lot lately. Last year's drought conditions set me off initially, then our harsher than usual winter combined with this summer's flip and flop weather means the thinking continues. It's a huge topic which I freely admit I'm struggling to get my head around. Tom Massey's Resilient Garden  at Hampton Court recently  tackled this topic brilliantly and was a timely interlude which gave me much food for thought. There he encapsulated the detailed research he'd found which informed both his show garden and book of the same name. I think it's one of the most important show gardens I've ever seen. It's clear the way I garden needs to change so that I have my own resilient garden. I haven't worked out the exact details yet, but Tom's book plus a couple of others (see below), alongside the rainwater management handout from the show garden's  sponso
Read more

Testing Times: Tomatoes

Image
  I've run a couple of tomato trials this year. The first is a revisit of the biochar trial with Oxford University I attempted some years ago (with a different organisation this time), and the second is a trial of a water gadget called Plantsurge which I was given to try at Malvern Spring Show earlier this year. Most of you have probably heard of biochar already and the claim that this inert, carbon-rich material can help soil fertility and plant health. The RHS information in the above link says results can be mixed, with reduced effects found in alkaline soils. This may help to explain the lack of difference I found in my previous trial as VP Gardens is on a lime-rich soil. Plantsurge is a different beast altogether. It's a strong magnet which is attached to a hosepipe as shown in the photo above. It's claimed that it softens water, with the result more like watering with rainwater. The higher nitrogen found in rainwater is thought to be beneficial to plants. Gardener
Read more

Chelsea Fringe 2014: Shows of Hands - Episode I

Image
The gloves NAH used to build the raised bed . The effects are L to R, top to bottom:  Original photo, Warhol, HDR, Green tint, B&W, Posterize, Boost, Cross process and Sepia Welcome to Shows of Hands - my Chelsea Fringe project for 2014! As you can see I've been having a bit of a play around in Pic Monkey for my first contribution. You're welcome to join in between now and 8th June 2014. The idea behind this year's project is to highlight the tool most precious to a gardener: their hands. How do I take part? It's simple. All you need to do is take a photo of hand(s) in a gardening context and then share it via your blog or other social media (such as Twitter or Facebook), then make sure I know you've done so. I've set up Mr Linky below for your blog contributions. The Chelsea Fringe photo on the right sidebar links to this post, so you can easily find it again when you're ready to add your contribution. If you share your photo on Twitter,
Read more

Make Use of Mildew

Image
On my garden patrol this morning I spotted some powdery mildew on a couple of my new Verbena bonariensis plants. I suppose it was almost inevitable as I prefer to grow my plants hard - this means no water for them unless they look absolutely desperate. This approach means plants root themselves more deeply and have a better chance of survival during spells of dry weather like we've had lately. However, it also means I run the risk of problems like today's, especially with any garden newbies planted late in the season. We've had a good drop of rain overnight, so this should help my plants survive. I'll mulch them later today to help lock in the moisture as it's water stress which encourages the mildew to take hold. I've also removed the infected leaves and sprayed the rest with a milky drink.* I'm also pleased to find there's a use for my infected leaves. Oliver Ellingham at Reading University has started a PhD - sponsored by the RHS - researchi
Read more