Understanding the unique qualities of a greenhouse or polytunnel

Understanding the unique qualities of a greenhouse or polytunnel

Understanding the unique qualities of each structure is ultra useful, and each has pros and cons which I illustrate here.

They are as valuable in winter as much as in summer and enable most of us to grow all year round. As well as do great propagation, and enjoy a garden space in the winter months

See also my 2018 video on this same subject, with an older polytunnel which you can compare to this one:

The polytunnel is 18x42ft (5.5 x 12.5m) and is from First Tunnels https://www.firsttunnels.co.uk.
The greenhouse is 12x25ft / 3.6×7.5m approx, from Woodpecker Joinery https://www.woodpecker-joinery.co.uk

Filmed and edited by Edward Dowding at Homeacres, SW England, mostly early in 2021.

More from Charles:

CD 60 Module Trays
In the USA you can buy these via https://allaboutthegarden.com
In the UK you can buy these via https://containerwise.co.uk/product/charles-dowding-60-cell/
or via https://www.refillroom.com/product-category/garden/
In Europe you can buy these via https://thefarmdream.com/product-category/propagation-trays/

To buy video garden guides with a unique search function https://charlesdowding.retrieve.com/store/#/

To buy one of my online courses https://charlesdowding.co.uk/product-category/online-courses/

To buy a signed book https://charlesdowding.co.uk/product-category/books/

To join an in person Day or Weekend course at Homeacres https://charlesdowding.co.uk/product-category/courses/

This is the dibber I recommend https://www.gardenimports.co.uk/product/charles-dowding-long-handled-ash-dibber/?v=79cba1185463

To buy t-shirts and hoodies with my exclusive no dig designs, use this link https://charlesdowding.teemill.com

50 Comments

  1. Joseph Bannigan on June 9, 2022 at 9:26 pm

    Hey Charles, I was wondering if you could advise on what capacity buckets to use for raspberry and strawberries? what would you say as the minimum litre capacity? Many thanks my friend.

  2. KM Sand on June 9, 2022 at 9:27 pm

    How thick is the Poly you use? What are your average low temps in your area.

  3. Cristobal V on June 9, 2022 at 9:30 pm

    Polarizing as in mediocre adaptation ?

  4. Philip Payne on June 9, 2022 at 9:31 pm

    Hi Charles, thanks for this video great information, I have two greenhouses, the first was a cheap polycarbonate one, the issue with polycarbonate is that it flexes in wind and several times the panels have blown out allowing the wind under the structure and before you know it, nearly all the panels blow away as the clips just cant keep them in place, I had to result to adding additional cross braces and screw the panels to them to keep them in place, also you get less light. So personally I wouldn’t recommend them. My latest greenhouse is glass which is much sturdier in wind, it was second hand so was a good buy but I did break a few glass panes when constructing it and one has since broke due to a bird flying into it. On the whole I much prefer the glass.

  5. Т - И - З on June 9, 2022 at 9:32 pm

    hello from russia – we have autumn – english weather – rains and fogs slush ))

  6. John Thomas on June 9, 2022 at 9:32 pm

    I have a no dig garden that I’ve run according to the CD calendar this year for the first time with great results. My issue is with watering in a polytunnel or greenhouse-do you use rainwater or tap? Tap water is chlorinated so imagine it does untold damage to the micro organism activity in the soil. I’m thinking of either collecting rainwater or storing tap water so it de gasses before putting it into an automatic watering system in there. Am I worrying unnecessarily?

  7. Andrew Lankes on June 9, 2022 at 9:33 pm

    Chinese Greenhouse methods is where it is at!!!

  8. Denise Brady on June 9, 2022 at 9:34 pm

    Thank you Charles that was extremely informative as I had often wondered about the differences. We in sub-tropical do not need them as far as I am concerned but I do see out in the country some farms have them. Cheers Denise- Australia

  9. Lone Wolf on June 9, 2022 at 9:36 pm

    Gueesing polytunel

  10. Leon Barnes on June 9, 2022 at 9:36 pm

    great video. nice to see a comparison isnt just about the cost and installation
    getting a secondhand aluminium greenhouse which i plan to use for starting seedlings off in the spring. also looking to replace my old polytunnel current is 21foot wide by 18foot long, salvaged some old commercial hoops and fitted and covered myself and trenched the edges, 14 or 15 years on its starting to get a bit tatty, more and more patches of repair tape.
    ive seen in my investigations that there are some companies with roof ventilation for their tunnels, though the cost of the vent kits are a touch extravagant.
    anyway, will be checking out a few more of your videos. thank you

  11. Sheelagh O'Malley on June 9, 2022 at 9:38 pm

    I have 2 polycarbonate 3m x 4m tunnels. Do you think they are somewhere in between the greenhouse and polytunnel?

  12. Tiles With Style — Diane H. Holycross on June 9, 2022 at 9:39 pm

    Thank you Charles for the comparison. We have what you refer to as a polytunnel here in East Tennessee USA. This year, I built rock sculptures in the raised beds, to generate heat below ground and a little above ground, during the night time hours. I learned this trick while living in Wyoming which is cold, cold, cold most of the year. It worked great to grow cool weather crops. Have you ever tried this before? Thank you. Diane

  13. Yoriichi on June 9, 2022 at 9:39 pm

    Are you using compost only as a fertilizer? No other chemical or organic fertilizer?.

  14. TheSwissGardenVlog on June 9, 2022 at 9:41 pm

    Great video, definitely helps my decision making process. I am considering investing in a small greenhouse but I have been looking at polytunnels as well. My biggest worry is the noise that the palatine on a polytunnel could cause on a windy day😏

  15. Alicia Cocoa on June 9, 2022 at 9:43 pm

    No se como demonios llegue aquí, pero que HERMOSOOOO! Yo quiero tener eso cuando sea grande, no es que yo sea una entusiasta de la jardinería pero últimamente mi madre me ah estado transmitiendo su pasión por la jardinería y quisiera que ella tenga un jardín similar a este.

    Psdt: El señor se me hace tierno jajajaajaja y mi mamá dice que se parece a su papá.

  16. Gardener42 on June 9, 2022 at 9:44 pm

    Oh & the algal film sticking to polyethylene is down to the affinity between algal lipids (or any fats for that matter) & plastics – it’s why plastic food containers often have a film of "grease" on them even after a hot wash. I’ve heard borax will aid removal but never tried it.

  17. Eddiejo Jonk on June 9, 2022 at 9:46 pm

    Very informative video Charles, Thank you! I live in the south of Sweden and have been researching Polytunnel vs Greenhouse. What I have read about here is that a greenhouse gets colder in the winter because the heat escapes through the glass faster than through the polytunnel plast. Could that depend than on the size of the glass greenhouse?

  18. p. S. on June 9, 2022 at 9:47 pm

    Brilliant job!

  19. Виктор Умнов on June 9, 2022 at 9:48 pm

    Ваши рассказы интересны. Спасибо за субтитры.

  20. Sunny SeaCat on June 9, 2022 at 9:49 pm

    Excellent presentation and discussion of both … air flow is critical and pointing out straight walls in the polytunnel was helpful.

    FYI: the stronger greenhouse may well be the wiser bet though with the GRAND SOLAR MINIMUM here and the incredible storms ahead (snow, hail, wind, sleet, electrical, etc) and mind-boggling challenges it will bring. You are so far ahead of billions in growing your own food – an enormous issue coming, too, due to the GSM, and food distribution as well.

    Been thinking that underground tunnels from one greenhouse to the next might be practical as it will be too windy to be above surface to get from point A to point B.

    Thank you from America.

  21. Fontanelli Consultoria e Projetos Ambientais on June 9, 2022 at 9:49 pm

    Great video Charles. Congratulations. One question about the polytunnel cover. How does it behave with hail? I have this to consider in my region as well.

  22. Fry on June 9, 2022 at 9:50 pm

    In the winter, you could have a small compost area to provide a little warmth to a greenhouse 🤓

  23. Leoni Dawson on June 9, 2022 at 9:50 pm

    Brilliant video as always! I do have one question though, have you considered the environmental impact of both? My concern is all that polythene, would a polytunnel still be your choice if factoring that in? Thanks 😊🌱

  24. C Church on June 9, 2022 at 9:56 pm

    Thank you for sharing your insights – very informative as always😃. Have you ever considered painting the wood white inside the greenhouse to improve light availability ? I recall seeing Curtis Stone do this to his timber frame greenhouse for that reason … but would be a decent effort give the size of your house!

  25. Marcelo Poggi on June 9, 2022 at 9:56 pm

    Hola Charles!!!… he descubierto en usted una persona encantadora y entrañable con mucho conocimiento y muy práctico en su modo de difundirlo. Su acción es de tremenda ayuda para quienes incursionamos en este maravilloso universo vegetal … y mil gracias por traducir al español sus videos!!!. Desde Argentina un fuertisimo abrazo!!! …y muchas bendiciones!!!!

  26. Cami Cri on June 9, 2022 at 9:58 pm

    Thanks for the comparison! It’s always good to find out pro’s and con’s before spending a lot of money! Have a great weekend, God bless! Hugs🤗🤗

  27. Ирина Самойлова on June 9, 2022 at 10:00 pm

    Здравствуйте, Charles. Наши дачные сезоны в России почти закончены и ваш канал будет приятным времяпровождением в холодные зимние месяцы. )

  28. Noga on June 9, 2022 at 10:04 pm

    Any reason you’ve not tried polycarbonate? Seems to be the best of both worlds.

  29. Ellen Koch on June 9, 2022 at 10:06 pm

    You have been so helpful, Mr. Charles. One more question – do you have to hand-polinate tomatoes/cucumbers in the greenhouse/poly tunnel? Thank you.

  30. Carmen Slee on June 9, 2022 at 10:07 pm

    My greenhouse is attached to my house which is very nice for winter planting. It was a very deep verander which was subject to winds that would blow away what was on it. Building a glasshouse on to it and enclosing, solved the problem. I just need to utilise it better. Getting loads of ideas and tips here!

  31. Gardener42 on June 9, 2022 at 10:07 pm

    I removed the last tomato plants & cucumber (jalapenos are still producing) last week (22/10) from my tiny 8×6 greenhouse, laid in 50mm of compost from the bay finished in April & planted out coriander, mustard, two different rockets & two lettuce varieties to see me through the next few months for salad leaves.
    Still waiting for the local council to reorganise their allotment strategy so I can get a polytunnel set up for protected growing (worried they’re going to close them to use for a business park).

  32. Mark W on June 9, 2022 at 10:07 pm

    A very nice explanation Charles,👍

  33. Henryka Augustyniak on June 9, 2022 at 10:08 pm

    Bardzo dziękuję Panu, za te przemyślenia, wnioski i rady. Są przydatne. Pozdrawiam Pana bardzo serdecznie i życzę dalszych sukcesów w uprawie. Pozdrawiam również kamerzystę, który każdą informację potwierdza opisem i obrazem. Przyjemnie ogląda się całość. Dziękuję.

  34. ok pen123 on June 9, 2022 at 10:08 pm

    Hi there Charles,
    Have you tried using a hot compost to heat up you greenhouse soil ?
    passing water pipes at a certain dept will allow the soil to be a additional thermal mass.
    the water flows thanks to thermal siphoning but you can always add some sort of bucket with a pump .
    heat rises from the soil and should heat up the plant in the process, just like floor heating in houses.

  35. Greenwood on June 9, 2022 at 10:09 pm

    Hi Charles, great video thanks
    Perhaps one of the biggest reasons for frost in the poly tunnel compared to the glasshouse is the big hot compost heap in your glass house. Have you tried one in the poly tunnel ?

  36. sid on June 9, 2022 at 10:15 pm

    Shouts out to my Somerset gang growing things the right way !! Was dragged to one of charles’ talks as a teenager and have been a dedicated follower of the teachings ever since.

  37. WalkingRonin Yes on June 9, 2022 at 10:15 pm

    where can we buy seed of spring onion

  38. Roger Hickson on June 9, 2022 at 10:15 pm

    Wood doesn’t get hot during the intense heat of summer. Most metals do, no matter what colour they are painted. I live in the South Okanagan valley of British Columbia, Canada. We have desert like conditions so it isn’t uncommon to see 34-35C + during the summer. All metal frames get hot and burn the plants if they are touching

    Love the compost idea in the greenhouse!

  39. Natalia S. on June 9, 2022 at 10:16 pm

    Ah, invaluable detailed video and info as always! I’ve had great success following your guides to a T this year and I’m now for the first time attempting to grow over the winter 😀 I have a small greenhouse (the length of the width of yours!) but yet another year the tomatoes seem to be cropping better outside than inside. It gets insanely hot in summer in the greenhouse, even with the shading net, large toms often have yellow sun scalding around the tops but the main problem is flower dropping. How do you avoid that? I havent seen you using any shading? Tia xx

  40. dan axel on June 9, 2022 at 10:16 pm

    "the corner of each circle" Love you Charles! Cheers

  41. Stephanie Hart on June 9, 2022 at 10:16 pm

    My £100 aldi polytunnel erected by me and a friend was great in spring / autumn last year but has just blown away and buckled in the wind. Looking at options , either sort is going to be much more and with professional erection now scheduling for next summer, I think I may get another aldi in the spring and hope!

  42. Jenny Johnson on June 9, 2022 at 10:16 pm

    I have a very small greenhouse Charles which is rammed during spring, but I could never have a polytunnel, as much as I would like one as we have really strong winds here. I really dont think it would withstand the onslaught of the winter winds. We get gales straight off the Solway. I may have to move!!

  43. Future Ghost on June 9, 2022 at 10:17 pm

    Thanks Charles. You’re a legend in the game.

  44. Peggy Helbling's Garden What You've Got on June 9, 2022 at 10:18 pm

    Brilliant Charles, I love your Pro’s and Con’s videos.
    Greetings from Windermere, Florida zone 9b 🇺🇸 68 °F this morning and only going up to 82° nice gardening temps👩‍🌾👍

  45. Amy Harris on June 9, 2022 at 10:21 pm

    Thank you, Sir Charles, for another excellent video. This is interesting. I had never heard of hoop houses or high tunnels until this past year, I guess I thought they were all "greenhouses" when I saw them. Could you share more details about your Dutch door solution on the bottom of the tunnel? Is that the same poly fabric just on a wood frame? Your red brick and wooden greenhouse with that lovely decorative trim is just a dream!

  46. Heirloom Mountain Seedswoman on June 9, 2022 at 10:21 pm

    Just made a DIY greenhouse so I can grow more seeds for my biz. Wonderful temp.

  47. Left Side Krew on June 9, 2022 at 10:22 pm

    It isn’t no dig if you’re using a shovel to add compost mulch it’s no till

  48. Leon Leese on June 9, 2022 at 10:23 pm

    I was looking for an 8feet X 6feet but I live on the Clwyd estuary just west of the river 800 yards and 1500 yards from the coast.
    The wind from the west is the main worry.
    If I buy a greenhouse I would prefer a rhino but a poly tunnel would be about £600 for a 10 X 8 but that would half my 22 foot square plot.
    8 X 6 poly tunnels are at the cheaper end of the market at this size would I be safe or go for the northern polytunnels 10×8?

  49. Kathryn Levin on June 9, 2022 at 10:23 pm

    Please shave

  50. Mary McAndrew on June 9, 2022 at 10:24 pm

    Hello Charles, great video as always! I’m hoping you can give me your advice, we’re settling into a new home (Scottish Borders) and finding the holes we’ve dug for the apple trees we’ve ordered are all filling with water and not draining, lots of clay. Do you think if we add lots of grit and sand back in with the soil, then plant them higher than ground level, that it will help? We’re thinking of hiring a mini digger to dig narrow trenches that may help to drain the area, it seems dry enough in summer, but there’s a lot of spring water draining off the hills near us and the area is boggy right now. Any advice is welcome! It’s my dream come true to be getting apple trees!

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