Definitions, Media and Mo-tivation; Luscious Lord Napier; Solar Inputs and The Laws of Thermodynamics

The challenges of the rural blogger. As I sat down this morning to write this post, with heavy rain and strong winds forecast by 10.00 am, the screen went dead – the power was off. Ah well, into the greenhouse as the drizzle started to intensify, with a few strands of half a dozen Clematis cultivars which have now grown to a point where it’s worth having a go at some cuttings. I’d no sooner harvested all the stems than the power outage, (the result of blown over trees on the line at Parc y Rhos), was restored.

Aconitum ‘Spark’s Variety (Monkshood) is a huge hit with larger bumblebee species just now, even early in the morning.

What joy was unleashed in the UK by the success and coverage over the last fortnight of the London 2012 Olympics. The United Kingdom of Great Britain and Northern Ireland which I’ve now discovered first officially came into being in January 1801 under King George 3rd, (though the Southern counties of Eire were partitioned in 1922) did indeed feel like it was GREAT. A great place to be, to live, and with a rich diversity of people and historical and cultural influences, and still capable of organising such a huge globally outreaching event almost glitch free. From our off the map, TV-less viewpoint, this realisation or perception was in part because of the enthusiastic and good humoured radio coverage, which we tuned into on BBC5 Live.

Our abiding memory will probably be missing the last few laps of 5,000 metre commentary as a result of an incoming phone call, and catching the replay of the final lap of Mo Farah’s epic victory on-line. It looked impossible that this slender athlete would hang on, as the pack massed at his shoulder for the final challenge. But, hang on he did, and after winning the deserved Gold in front of a packed and ecstatic stadium, the necessary post race interview back on the radio elicited the brilliant quote as to how he had achieved such Double Gold success. “Hard Work and Grafting”.

Now I don’t know the ins and outs of financial support for our top Olympians, but it seems that part of the huge psychological boost to the country after a pretty miserable summer, and continuing economic gloom (the Bank of England announced during Olympics fortnight that they have revised down their growth target for the year to 0%. Is that growth?) has been the involvement of ordinary people, and the Mo-tivation of the competitors. Dedicating at least 4 years of their lives to achieving a fleeting pinnacle of sporting success, with no obvious or immediate financial gain – though many will reap rewards from now on.

Many other spheres of human activity involve similar non financially driven Mo-tivations. Indeed in a way one could argue that gardening has a similar patient grinding, grafting ( if not generally as energetic!) approach to achieve that elusive and often fleeting result, perhaps many years or decades ahead, of a planned or even better serendipitous, flower, tree, scent, taste or vista. With almost no financial motivation at all. And gardeners do seem to be a pretty happy bunch (most of the time).

Should politicians and broadcast media reflect on the merits of taking a more patient longer term view?

So when the Olympic euphoria has dissipated will lessons have been learned by the mainstream news based media? Or will they leave behind their upbeat enthusiasm and return to negative cynicism? And the Bosses of Industry? And the Banks?  Where we are constantly reminded that only enormous salaries and bonuses will attract the right calibre of people. (To achieve what? Maintain the Status Quo?). Perhaps with the recent introduction of the verb ‘to medal’ into the pundits’ vocabulary, and the evident joyous flip side to media coverage, some other reversals of previous definitions are called for.

How about ‘To Meddle’ (sic) – To achieve the highest possible goal through personal sacrifice and dedication.

And ‘To Bank On’To exploit one’s customers with minimum effort, and maximum deceit for extraordinary personal financial gain?


Since my last post, the nectarines have been ripening, and devoured. I can’t think of anything I’ve ever grown which has so exceeded my expectations. They positively drip luscious juice and flavour. But it takes a while to get used to how and when to pick them. After all, like many in the UK, we’ve become used to supermarket punnets of richly and evenly coloured inviting fruit, which are often as hard as tough apples and possessing almost no flavour. I guess this is usually because they are picked unripe, and like many commercially produced tomatoes are then ripened off the plant using ethylene gas in storage facilities. Since our fan trained trees are grown facing South in a greenhouse, at least half the fruit remains pale yellow/green.

This gifted Aussie T-shirt wasn’t picked for this photo shot, as can be judged by its grubby condition, and indeed the gardener’s fingers. But the image seems quite appropriate for these well sized, juicy Welsh Lord Napier nectarines, and the fruit rarely last more than a few minutes off the tree.

So I’ve found the only way to test for ripeness, is gentle pressure on the skin. Even when obviously soft, the fruit don’t seem to twist easily from the stem in the way a ripe apple will. The consequence is a tear in the skin near the stalk which oozes juice. But what juice!

The glistening surfaces and drops aren’t from the fruit being washed, its just the juice, WOW. The white fleshed Welsh grown Lord Napier nectarine.

So impressed am I that I’ve researched 2 other varieties, Humboldt and Pineapple both available from our Lord Napier supplier, F.P.Matthews, which I hope to squeeze into the greenhouse this autumn to extend the season beyond the 3 weeks or so that Lord Napier should give us. And who was Lord Napier?

The nectarine was first grown in the UK in about 1860 (so not that long after Britain first became Great!), and was probably named in honour of the 10th Lord Napier, Francis Napier, who following in his father’s footsteps, had a very successful career in the overseas diplomatic and political field, including a stint in China, which is thought to be the original home of the nectarine. It seems clear from what I’ve read that you do need at least summer greenhouse protection in the UK for this warmth loving tree to fruit successfully, but I still can barely believe the number (15 per tree), size and quality of the fruit we’ve obtained in this first year after planting, and in this terribly light deprived summer. If you’ve got a greenhouse or poly-tunnel with a spare corner, do think of growing one. I reckon if we can grow it so well up a Welsh hillside, you could grow it anywhere. It obviously also thrives with the humid summer conditions we try to maintain for growing our tomatoes.

I’ve mentioned before that I think that the increased warmth in our greenhouse, from the combination of heat sink path, insulated lower walls and warm stored water in containers does aid growth and fruiting in both tomatoes and nectarines. But after hearing Bob Flowerdew mention using ordinary water filled bottles as warming heat sink aids to growing water melons outside in Norfolk, I thought I’d take a few temperature readings with my digital point and shoot thermometer. They’re shown below with the images of where they were taken.

The South facing, internally insulated dark stained greenhouse. On a still day around noon, after about 5 minutes of sunshine following on from a cloudy morning the surface temperature of the wooden door was 47 degrees C. Is there an advantage in having a dark stained/painted greenhouse base in a cool climate? Ambient external air temperature was 17 degrees C.

The water in the clear bottle, which was 17.5 degrees C from the tap at 9 am, had risen to 22.5 degrees C. The black painted 5 gallon water container was 24.5 degrees C. The root watering container in the pot was also 22 degrees C.

The floor to apex black pipe which connects with a pipe at the bottom of the central channel stone filled heat store, registered about 22 degrees C at its base, rising to 45 degrees C half way up. The insulation filled black food trays were 29 degrees C.

The central heat sink channel was 26.5 degrees C in the centre, and 22.5 degrees C either side, which is nearly the same as the greenhouse side bed soil temperature of 21.5. This roughly 4 degree C temperature difference from the centre of the path to the outside seems to be consistently maintained at all temperature levels. The greenhouse door is always left slightly ajar in sunny weather and the roof has 4 auto vents. (I amended this section 2 days after posting – on a warm but terrible wet, windy grey day, I checked temperatures again. External air temperature was 17.5 degrees C. Inside the greenhouse the whole width of this central path/heat sink channel was 18.5 degrees C, i.e. no side to centre temperature variation. Clearly there had been no sun all day, and the maximum temperature I could detect on the vertical black pipe was 21 degrees C. In spite of this it actually felt much warmer than outside, with no wind or rain. I take this as confirmation that when the sun DOES shine, temperatures rise, air is drawn up the black pipe so drawing air into the stone filled base, and a heat store effect occurs, as the stone filled base warms. In the winter months, sunny days are often followed by colder nights, and so this passive working of a greenhouse heat store may still have value, though only, or mainly, in sunnier conditions.

I discovered that the energy required to raise 1 litre of water by 1 degree C is 4,186 joules. Which seems like a big number. And the sun is capable of doing this for nothing. But what’s a joule? Perhaps it’s easier to talk about watts, which we’re more familiar with. The trouble is that a Watt is a unit measuring the rate of delivery of energy.

1 Watt means 1 joule of energy per second.

Thus a 2 litre water filled bottle -a typical large milk or fizzy drink container – which has been heated by the sun in the greenhouse by, say, 5 degrees C above its starting temperature, ( as I measured above), would have needed 41,860 Watts or joules per second of energy input to have achieved this temperature rise (5 x 2 x 4,186.)

WOW. Even more impressive, and of interest because what goes in, must come out. And water has a better thermal capacity than almost any other commonly available material. So, all those free watts which the sun has put into heating the bottle of water by 5 degrees C will, in due course as the sun sets and the air in the greenhouse starts to cool, be given back from the water into the greenhouse air.

Free Power! At this point I needed to know more and, struggling on-line, phoned my guru on the laws of thermodynamics, Kevin.

Kevin, How quickly will the warm water return it’s energy into the air of the greenhouse?’

Well – this a complex subject. It depends on ambient air temperatures, air currents, what the bottle is made of, water currents within the bottle, what the bottle is standing on. But basically, the heat will be lost eventually from the bottle mainly by radiation, partly by convection (because of air moving over the bottle surface), and partly by conduction through the base of the bottle into the surface it’s standing on. And this process will, (as I suspected), follow an exponential type curve, losing most of the heat early on, then the rate of heat loss tailing off as the water temperature becomes more similar to that of the surrounding air.’

Many thanks, Kevin’.

I hope that this is a fair summary of our chat. What will certainly happen is that those 41,860 watts, or joule seconds, will be dissipated, and in so doing tend to keep the greenhouse warmer than it would have been. (Equivalent to a tiny 100 watt heater working for about 7 minutes – 418.6 /60). And this is just one 2 litre water bottle. After a quick estimate I reckon that in our 14×8 feet greenhouse, it would be simple to add about 120 of these bottles peripherally round the narrow concrete base, in a single row which would potentially equate, with the above parameters of water temperature raise, to 14 hours of a 100 watt heater running in the greenhouse – albeit not in a uniform linear fashion.

Further to my own attempts to keep the greenhouse frost free this last February by burning Tea Light candles, it seems that the output of a single tea light candle (which kept things just above freezing with about 5 degrees C of frost) is about 60 watts. Click here for discussion of the physics and maths of candle burning. So whilst the water bottle’s 100 watt output isn’t massive, it should be enough to both even out day/night time temperature fluctuations during the summer, and also help with keeping the greenhouse above freezing during the winter. Needless to say, I’ve started saving milk bottles, and since we get through about 3 a week, should have collected the necessary number in under a year.


All those bursts of solar energy triggered this pristine Small Copper butterfly, Lycaena phlaeas, to emerge and nectar on Erysimum “Bowle’s mauve” within the last 10 days. One of my favourite butterflies.

Another new insect for me at Gelli. It flew in short straight rapid bursts, hovered briefly in one spot, nectared very briefly from these Stachys flowers, and seemed to patrol this area aggressively. It’s behaviour was fly like, but its eyes, antennae and abdominal markings are more like a wasp or bee. It took ages to take any usable images, since it was so rapidly mobile. Any suggestions?

Having seen honeybees on Hydrangea flowers in France, it was nice to photograph some on a few of our lace cap Hydrangeas over the last week, the first bees of any kind that I’ve ever noticed on Hydrangea blossom.

Rose ‘Grouse’ is exceeding expectations as well. A mass of attractive, scented and bee appealing flowers starting in early August, with really healthy glossy green foliage, and perfect for training over a wall, which is where we have it.

One of the Clematis cultivars I’m trying to root cuttings from. C. ‘Blue Angel’, to the left below.

Hydrangeas are approaching their peak right now around the mossy croquet lawn.

At last on August 12th we harvested our Broad Beans, nearly 4 weeks after the date of last year’s harvest. The yield was 11.5 lbs from 5 dumpy bags, (plants were spaced about 9 inches apart each way), with sufficient extra pods for seed saving for next year. So eventually a marginally higher yield than last year.

A mixture of Stereo and Witkiem Manita, grown from saved seed last year. I guess eventually we’ll move towards a Gelli variant Hybrid Long Podded Broad Bean?

I managed to capture a few shots of the annual game of Swallow feather tag, when an individual swallow – a juvenile I guess, flies off with a feather in its beak and tries to avoid losing it as its relatives join in the chase.