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Last Frost dates Cornwall

I'm still quite new to gardening. I'm getting extremely confused about last frost dates! According to a website mine is last week of march but this seems early compared to things I've read. Does anyone from Cornwall have a rough idea? Many thanks 


  • BenCottoBenCotto RutlandPosts: 2,181
    It depends on lots of variables, not least being whereabouts in Cornwall you are as this map shows

    A further difficulty is the map shows average last frost dates so there is a 1 in 2 chance there’ll be a frost after the date shown. Also you might want to distinguish between ground frost and air frost as well as considering what you’re growing. Frost susceptible plants don’t necessarily turn their roots up the moment the temperature touches 0° C. I have petunias in the garden right now coping admirably with several nights of temperatures well below freezing.

    Then you have to give thought to where you are growing these sensitive plants. There’ll be pockets of your garden much more sheltered from frost than others.

    If I were you I would check several of these ‘last frost’ websites and try to get a consensus date. About then look at the weather forecast and if it looks encouraging then get sowing but with a fleece at hand to cosset your seedlings if the weather looks unfavourable. Even if you have to wait two or three weeks till after the date you could actually have planted in any given year, the gap between the date of flowering or harvesting will have shrunk to just a few days from the original 14-21. Practise patience.
  • Hi thank you for your response. I'm in the falmouth area. This is where I'm getting confused! I have an unheated glass greenhouse and I am really trying to figure out what will survive in there as a mid point to outside as I am planning to grow alot. I have strawberry plants in there that haven't gone dormant and continued to grow  and even my venus fly trap has grown back early so I think it must keep reasonably warm. Its more wanting to get a bit of a head start on some frost tender plants in the house then hoping to move to the greenhouse at the end of march for a couple weeks. Don't think I've ever seen frost after March but tbh not paid attention before gardening! Would something like cucumbers be ok in a greenhouse in March with fleece? 
    Our weather is bizzare, seen lots of echiverias etc unfleeced and still alive in my area! 
  • stephentamestephentame Southwest EnglandPosts: 86
    I'd be very surprised to find any frost in a greenhouse near Falmouth in mid March.
  • Me too! I don't think the frost is getting in now. I'm pretty sure last March it was really hot. I also planted potatoes mid Feb last year (didn't read the instructions) but they grew. Think reading online in making me doubt where as last year I chucked stuff in wherever and crossed my fingers. I chucked a load of lavender seed in a pot and left outside in Feb or March and loads germinated.
  • TeTe Posts: 193
    We are South coast and I’m sure you’ll find no frost mid March, if I remember correctly March 2020 was quite pleasant, we are approx 90 miles from you
    "There are a terrible lot of lies going about the world, and the worst of it is that half of them are true"
  • Awesome glad I've managed to get reassurance from people a bit more local as all the seed packets are quite late planting compared to our frost dates but I guess they are based on averages :) 
  • BenCottoBenCotto RutlandPosts: 2,181
    This site allows you to scroll back over the last 12 years to see Falmouth’s weather at a glance

    It looks like there was a frost on March 30th 2020 though anything in a greenhouse would be safe.
  • Awesome. Thank you! 
  • I have been trying to find out about frost dates as I am also new to gardening and, coincidentally, I also live on the south coast of Cornwall, near Fowey.  I found the Newquay Weather Station website a few days ago so figured that's close enough to me and for the last ten years or so it reports the latest frost as being early April but usually earlier than that.
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