Lagging; Logging; Serendipitous Swarming; Blogging in Perpetuity; and Solar Chimney and Greenhouse Heat Stores

“Gosh, I LOVE your fabulous hips“.

“Would those be mine or Fiona’s, you’re referring to, Rosemary?”

Not the conversation I was anticipating with our lagging and glamorous garden guest on Friday, as we enjoyed the sunshine on a post prandial garden stroll. But worth recording, since so far September is erasing the memories of soggy August. In fact the hips in question belonged to Frau Dagmar.

More specifically Rosa rugosa ‘Frau Dagmar Hartopp’ or ‘Frau Dagmar Hirstop’ to give it its alternative name. And of several rugosa roses we find thrive here, it’s undoubtedly the best, having healthy disease free foliage on a 1.5 metre bush and wonderful large, single, scented, clear pink blooms from early May right through to October. As Rosemary also spotted, the flowers, which have considerable insect appeal for their golden pollen, are followed by large deep red hips which contain masses of viable seed.

Originating from Germany in 1914, it definitely justifies it’s AGM from the Royal Horticultural Society for garden worthiness. Last October I saved the seed from several hips and have had really good germination, although none flowered this year, so next year I should have some ‘children of the Frau’ flowers to assess. Having given several seedlings away already to good homes, I have no idea where the remainder can be squeezed into the garden though.

The Frau’s numerous offspring – in marked contrast to just 3 seedlings I managed from the equally attractive hips of Rosa moyesii.

I noticed this week in the latest seed catalogue to arrive in the post, that you can now purchase packets of the amusingly named ‘Bishop’s children’ Dahlia seed, derived from the wide range of Dutch bred ‘Bishop’ prefixed dark-leaved Dahlia cultivars which were produced following the resurgence in popularity of the old dark-leaved ‘Bishop of Llandaff’ cultivar in the 1970’s.

This Welsh sounding Dahlia does indeed have an intriguing, and Welsh origin, which I gleaned from the excellent ‘Garden of Eaden’ blog which you can access by clicking here. Bred in Cardiff in 1927 by Stephen Treseder, it was originally known as ‘Bishop Hughes’. But the eponymous Bishop was unhappy with having his name used, so it was changed to simply “The Bishop”. But this ran foul of nomenclature etiquette prohibiting the use of a ‘the’ word. So it became “Bishop of Llandaff”.

But its dark-leaved origins are more sinister, lie further back in time, and across the Channel, where in 1884 the French nursery of Rivoire introduced the first black leaved Dahlia, and called it the strangely spiritually negative ‘Lucifer’. We don’t grow ‘Llandaff’, at least not yet, but have been really impressed with D. “Bishop of Auckland” in our first year of growing it. It’s a medium height, strong plant which has flowered really well since early August, and proved to be very attractive to many bumblebees and flies.

.Dahlia ‘Bishop of Auckland’.

But the spring planted tubers will have to overwinter where they are in the ground, at the halfway depth in a double tyred tier, to keep their place in the garden. I’m not into lifting and storing the tubers. I haven’t yet been able to save any seed from our own ‘Bishop’, though I have just collected some in the last couple of days from a fabulous lilac/mauve floriferous D. merckii plant which did survive the last, harsh winter in an identical location, benefitting from the extra warmth and better drainage in our matrix garden. D. merckii hails from the hills of Mexico originally, and plants can reach flowering size in just one growing season. What should these offspring, which may have cross pollinated with the Bishop be called I wonder, if any turn out to be dark-leaved? Mexican devils perhaps?

Dahlia merckii.

D. merckii seed head, about ready to harvest.

The interesting club-shaped dark seeds.

Lagging has also continued to be pursued in the greenhouse using water filled 2 litre bottles, in anticipation of the colder weather ahead, and making use of the much higher thermal capacity, or specific heat value (SHV) of water when compared to nearly all other materials.

In our own greenhouse set up, the central heat store channel is filled with rubble stone. Stone has a typical SHV of 800 joules per Kg. Water on the other hand has an SHV of 4,000 joules per Kg. This is the amount of energy required to raise the temperature of 1 kg of the material by 1 degree C. Equally it is the amount of energy given off when the material cools by 1 degree C. Even allowing for the fact that stone is about 2.5 times as dense as water, it means that a fixed volume of water beats stone as a heat store by a factor of about 2. So, I reckon that the more water I can place in bottle stores into the greenhouse the better. In addition, being a liquid, heat moves through the water with convection currents much more easily and evenly than it does through stone.

Inspired by the recent very cold late August night, (record breakingly cold in some UK areas for an August night), I thought I’d take some temperature readings inside and outside the greenhouse over a 24 hour period to try to demonstrate how effective or not the greenhouse heat stores are proving to be. I have an idea that they’re working very well, given how the tomatoes and nectarines have ripened in spite of lack of sunshine this year. Much is written about the need for light to ripen tomatoes, but it’s temperatures above 10 degrees C which are vital – even at night. And growing smaller fruited tomatoes which will ripen before most larger fruited cultivars.

I think that next year, given the poor summers here, I’ll just grow smaller vine tomatoes from my own saved seed, and give the larger Marmande and Roma types a miss –  they were at least  6 weeks behind the smaller fruit.

I hope the graph below is clear enough, and will explain that the temperature readings were taken from:

  • An outside Cornus leaf about 4 feet above ground level, to the front left of the greenhouse.
  • The bare ground just in front of the greenhouse door.
  • A tomato leaf inside the greenhouse about 4 feet above ground.
  • The central stone heat store path surface.
  • The top part of a 25 litre black painted water container sitting to the side of the central heat store path.
  • Mid way up the un-perforated black plastic pipe at the far end of the greenhouse which connects to the perforated soil pipe lying at the base of the heat store path.

I’m indebted to Fiona for spending ages on the computer to master graph production on Excel, and for producing an image which I’ve uploaded below.

The ‘Black Pipe’ graph is the upper and more yellow line, than the reddish colour of the horizontal label, and the readings were taken from 8/09/12 to 9/09/12.

What interested me was how the temperatures of the external leaf and internal black pipe surfaces on a sunny but not hot day, moved through a much greater range, and much more quickly than the heat stores of the central stone filled channel, and large black water container. By hanging onto a fair bit of their heat stores overnight, these stores of energy helped keep the internal foliage temperature up for longer (I think!). I discovered today a fascinating, intelligent and amusing forum discussion on greenhouse heat stores in the U.S.A., which contains much of interest. From now on I shall refer to it as a greenhouse heat store, and not a greenhouse heat sink. Technically a heat sink is used in mainly electronic product designs to describe a structure which dissipates heat – much of the U.S.A. discussion made me realise that in hot parts of America, cooling greenhouses down is a significant issue, whereas for us here, keeping them warm is what it’s all about. Click here for the forum’s thoughts.

Researching the idea of using my warming black pipe to passively draw warm air into the heat store stone channel/path, I discovered that my serendipitous design could be described as a form of solar tower or chimney. There’s more on the concepts of solar chimneys if you click here, but I was even more interested in a German engineering firm’s prototype for a solar chimney design of power generation plant, which was set up and operated in Spain. Here, rapidly rising warmed air accelerated up a central solar chimney and was used to drive a turbine to generate electricity. Click here for much more about the 50 KW Manzanares Solar Tower. This plant used black painted water pipes, beneath a low glass panelled ceiling, to maximise absorption of solar radiation. This created greater temperature changes and faster air movements, and then delayed cooling after dusk thus helping power generation operations at night once the sun had set. So perhaps the next thing is for me to bring out some black paint and get painting all these milk bottles for even better daytime heat absorption. Any one new to the blog can see the photos of my central heat store path construction by clicking here.

And to show that there really is nothing new under the sun, click here for another amazing design and build solar heated and cooled greenhouse, again from America and dating from 1978, which relies on a 9 feet deep wet mud greenhouse heat store beneath the greenhouse floor, which puts my puny efforts to shame.

A few dry days has meant dusting off and sharpening the chainsaw chain for the annual bout of wood store replenishment. We’re still way ahead of ourselves with quite a lot of felled timber waiting to be processed and put under cover, and first off this autumn is dealing with a large centrally rotten ash tree which was actually felled, part ringed up and shifted 18 months ago. It’s now being logged up and stored whilst at the same time clearing some ground which we might use for additional poultry foraging.

Always something to ease yourself into after a few months without handling a chainsaw, and as we discussed with friends last night, most fellow chainsaw users need to remember the potentially lethal close shaves they’ve had in the past, before tackling anything risky. If in doubt call in a professional!

Curiously, it also seems that most of us who have ever used the horrible orange expanding polyurethane foam beloved by builders for gap filling and window fixing also have a wealth of horror stories of lucky escapes as the foam has expanded beyond our wildest expectations, and not just filled gaps, but entire usable spaces. Beard filling topped the list as most amusing, though potentially serious, experienced.

An earlier than anticipated return home after aborting a trip to the coast on the previous sunny Saturday meant witnessing a temporary invasion of honeybees into the garden. Not a real swarm, simply huge numbers being drawn into the garden by the opening flowers on the many clumps of Sedum spectabile ‘Autumn Joy’ which I’ve gradually bulked up over the years. But we’ve never before witnessed such swarm like numbers of honeybees in the garden at the same time. We grow a few other forms of Sedum, many of which look lovely, but none attract insects to the same degree as ‘Autumn Joy’. And editing my spelling of spectabile, I’ve discovered that this is another AGM plant, although under the disguise of the synonym of Sedum ‘Herbstfreude’. It looks like there’s a foreign, and unplanned, flavour to the featured plants in this post. And for all the years since we first acquired this from Fiona’s parents’ garden, we’ve known it as ‘Autumn Joy’. Which, frankly, it is when grown en masse.

It always attracts lots of flies, bumblebees, moths and butterflies, and a week earlier there’d been hundreds of these all busy on the flowers and just a single honeybee.

But this particular late mid September afternoon, there were hundreds of honeybees on the flowers. The whole ‘event’ lasted perhaps a couple of hours, and as the light failed the bees started to take off with an orientating couple of circuits before flying roughly South West, in the general direction of the closest known hive over a mile away. Interestingly they were flying home almost directly into the wind, so any scent hadn’t been blowing in the direction of the hive. But presumably scout bees made it back to the hive earlier in the day and were sufficiently impressed with the quality or quantity of the Sedum nectar supply to call their friends over. Also, none of these bees were collecting pollen, whereas in another part of the garden there were other worker honeybees, though in ten’s and not hundreds, which were working the Hydrangea flowers for pollen. Do hives shift worker activities to predominantly nectar collection later in the year, with winter approaching? If so, is growing lots of Sedum spectabile ‘Autumn Joy’ a good idea for bee keepers after poor summers?

Sunday saw cooler temperatures and the return of rain, and on a misty, cool Monday morning, there were no active insects around at all, but a couple of bedraggled and ailing worker bees left on the closed wet flowers, which I guess never made it back to the hive.

I’ve recently read in one of my spam ‘comments’ folder items which WordPress filters out for me, and prevents ever being published on my blog, that “my SEO optimisation isn’t great; I don’t have the correct number of H tags; I don’t have RSS feeds,” etc. And I don’t have a clue what all this means. I’m encouraged to “embed tagged words in bold, and italics so many times per page to optimise new Google panda search algorithms”. Bemused? So was I.

I post blogs because I want to, not to achieve SEO optimisation. It is nice to know that someone else reads a few of my musings, but it’s quite a slog to put a post out there, floating in cyberspace, and the thought of altering content to maximise appeal isn’t for me, I’m afraid.

This then got me thinking about the motivations of the typical (if there is one) blogger. I have now blogged for long enough to work out that there’s a very high drop out rate from blogging, typically after just a few months, as the pressure and time commitment of regularly writing something of value, wears you down. Whilst thinking about bloggers’ motivations I heard about the recent idea by a Dorset based undertaker who suggested engraving a bar code on a loved one’s cemetery headstone to provide a scannable link to a relatives’ approved life history of the person buried there. The idea has apparently received widespread approval from many recently bereaved families as giving a better idea of the achievements of a lifetime than an apt, but brief epitaph, carved into the memorial. The graveyard visitor will be encouraged to scan the bar code with the latest mobile phone technology to find out more about the deceased.

Does the concept of a legacy play in the minds of bloggers? Has anyone ever researched this?

The answer of course is yes, (i.e. researched blogger motivations) and for me the most interesting piece of research was by Kjellberg, which you can access here. Many of the motivating factors of the bloggers interviewed were ones I could personally concur with. For myself there is also a small sense of being able to leave behind something of value about the garden we have created, and indeed us, the gardeners, for posterity once all has degenerated as it surely will, once we leave or lose the plot – however that’s interpreted.

But any reliance on simply a digitally based cyberspace immortality, whether through blogs or bar codes is surely foolish. So, for now, I’ll content myself with the present, and my observations of this very specific place which feeds through into the ideas, words and images which create these posts. This process still fascinates me and keeps me out of greater mischief on (mainly) grey wet days.

And finally from the garden:

Croquet lawn Hydrangeas.

Small Copper, Lycaena phlaeas, butterfly on Asters.

Morning clouds.

Light in the copse.

And on the magic mushrooms.

And on the Anemone japonica along the front path.

And their silhouetted form on the cottage wall. This required the photographer to lie prone on the cobbled path, in night-shirt and dressing gown, to avoid his shadow spoiling the image.


2 thoughts on “Lagging; Logging; Serendipitous Swarming; Blogging in Perpetuity; and Solar Chimney and Greenhouse Heat Stores

  1. Erudite, indeed! I do enjoy your scientific experiments and the sense of wonder the results engender. There is though a sense that the the literature study follows the experimentation, rather than the other way round??! I remember being roundly criticised for this in the Chemistry lab at university. But where’s the fun if you can’t find out what happens out there by experimentation, before learning the boring theory!!? I’m also interested in how Fiona made a jpg out of an Excel graph. When I did it in Blogger, I found I had to import the graph into PowerPoint, where there was a facility to produce jpegs directly that could then be uploaded to the blog. Did Fiona use a more sophisticated method (or did you just cheat and take a photo of the graph)?

    Oh and by the way, onshore and offshore winds are excellent examples of the different specific heats of water and earth.

    I am of course, as usual, completely baffled by the erudition on the main point of the blog, the plants, but the photos as usual are stunning, and really gifted.

    As to motivations for blogging, Once upon a time, I received a random comment from a blogger in the US, responding to my blog. She was a student at Washington College and she pointed me in the direction of Thoreau and his love of walking as a means of thinking, and more interestingly in this context, the use of blogging as a means of teaching creative writing at university, the blog as an informal place to collect and share ideas in an organised timeline in order finally to collate the good stuff into a finished paper for publication. The site is a fascinating read and I don’t pretend to have done it justice.

    Great stuff, Kevin

    • Hello Kevin,
      Thanks for the comment, but I’m not so sure about the erudition bit, more verbal eructation. Re the jpegs, as you correctly surmised, Fiona had to print off a graph, connect up the dots with felt tip, and I photo’d it and uploaded it as a jpeg (you can spot the dirt spots on my camera sensor, I’m afraid on a clear background- must get it cleaned some time)…..hence my deepest thanks to her…I would have given up after 5 minutes.
      You do indeed detect more than a bit of wonder in my discoveries, although most of them have no originality at all….if we’d had a TV all these years, maybe it would all have been unnecessary, since I’d know all this stuff anyway! But of course where I agree with you is that the great thing about blogging is the freedom to do your own thing, follow your own ideas, get really excited, and then discover that someone on the other side of the globe, did vastly more impressive work decades ago! Still I do constantly think how great modern technology is for enabling me to put all this stuff out there using a frying pan on a pole pointed heavenwards.
      Thanks you for the link. I’m a Thoreau fan anyway, so will follow it up when the rain returns, the nights draw in, and the temperatures drop a bit more….. which is probably when you’ll be visiting Hobbiton?
      See you soon, BW Julian

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