PBS Forum

Quote from: David Pilling on December 17, 2023, 04:30:16 PMOn weather stations I beg to differ. The link I gave goes to a map that can be zoomed to street level and the weather station belongs to a neighbour I know,

That maybe the case with you.
I could see nothing but the same points close to me as used by the Met' Office.

I am unsure if the Met' Office actually maintain very many weather stations themselves - two near here are airports, one of them military.

The diesel figure was never going to be correct at 2p/kWhr.

Presumably central heating oil has escaped the application of VAT that now applies to red diesel (presumably, red diesel no longer exists)? If so, central heating oil will probably now be the prefferred choice of van drivers who won't pay for fuel at "full" price?

I just buy vehicle fuel - I need it, so buy it, so have no idea what they are in the UK now, except that petrol contains several % ethanol.
I wonder where all the spent oil from commercial premises went before conversion to diesel substitute was an option?

As a point of interest, which surprised me when I did some digging after someone asked, to make vegetable oils compatible with diesel engines, it has to be partially hydrolised, which generates glycerol as a by-product. (All natural fats are tri-glycerides - three fatty acids attached to one glycerol molecule).

I have no idea what is done to vegetable oils to make it burn like Jet A1, quite possibly the same thing?

Quote from: David Pilling on December 17, 2023, 04:00:28 AMWeather Underground is a useful source of more local weather data

I have not searched in detail, but the locations look to be the same as the Met' Office use. If you use the Met' Office website, you put in your postcode and a list of local weather stations appears on a drop-down menu  and you choose which one you want, which appears to be the same.

Quote from: David Pilling on December 17, 2023, 04:00:28 AMBubble wrap seems popular in the UK for lining greenhouses in the Winter. The temperatures are probably around the sweet spot for it.

I am unsure how there can be a "sweet spot" for insulation of a greenhouse when bubble-wrap costs peanuts, assuming that you don't throw it away every year, or is free. I suspect that insulating the bench cost around £4-5, I have not worked things out in detail.
I only have to save something like 15kWhr and I am ahead. I am sure that there will be U values for bubble-wrap online somewhere, but life is far too short.
The heat lost from the insulated bench, into the bulk of the greenhouse - 8 x 12 - raised the greenhouse temperature by about a degree, assuming all that heat came from the insulated bench, ignoring any contribution from the concrete floor etc.

Quote from: David Pilling on December 17, 2023, 04:00:28 AMthe determined reckon on £0.02 for a diesel fuelled heater off ebay.

Diesel, on full combustion, liberates around 44MJ/kg.
One kWhr is 3.6 MJ.

So 1kg diesel when burnt liberates a little over 12 kWhr of energy. Diesel is close to a density of 1, so, near enough, 1kg is 1 litre. A litre of disel is around £1.45, so IF all the energy could be used, heating using diesel would cost around 12p per kWhr - more expensive than domestic mains gas.
However, two problems - you need ventilation (an oxygen supply) for combustion, you do not for electric heating, and ventilation means lost heat, also the combustion products must be disposed of, which also means lost heat.

Modern household boilers burning gas, all singing, all dancing, can get around 90% efficiency. (Even old gas boilers achieve over 80% efficiency. Which is why the economics of changing an old for a new boiler, so long as the old one works, do not stack up. It will depend on fuel prices, but generally, the payback period for the new boiler is longer than the expected life of the new boiler.)

Diesel is pretty close, chemically/in terms of combustion, to central heating fuel. I have never heard anyone suggest that oil central heating was a fantastically cheap option in the UK.

Just by way of information..............

My collection was started again a couple of years ago, so is not huge - overspilling a 12 x 3 bench now, but I was determined not to heat the entire greenhouse, as mentioned in the thread referred to.

I have rehashed everything properly (last minute, only a week or two ahead of frosts).

The greenhouse long axis is north-south, so the great majority of light comes in via the south end and roof.
I have double bubble-wrapped the west- and north-facing walls from just below bench level to the eaves, and single bubble-wrapped the south end (my greenhouses sit on one course of concrete walling blocks, so are an extra 10 inches (?) taller). The east side of the bench is the path within the greenhouse.
At eave level, I have secured some 3 foot wide wire netting, as a "roof" over the bench, supported on some 8mm studding and small battens (lengths of broom handle).
I have stretched single lengths of stout wire at eaves level, againt the wall, and along the front of the wire netting.
A length of bubble-wrap hangs on the front wire, like a curtain.

When the forecast is for under 5C, I "draw the curtain", and lay a length or more of bubble-wrap on the wire netting. It isn't "air-tight", but everything overlaps so there are no huge leaks.

I bought a couple of plug-in energy "meters", and the 12 x 3 x 2.5 foot cloche used 4.5kWhr of electricity to maintain 6C difference to ambient over a period of 15 hours (5C in the cloche, average -1C outdoors (from local Met Office weather station data and probably a little cooler here, maybe an extra degree, as I am outside of town)). So, around 0.3kWhr per hour. Two consecutive nights were very similar, both in average temp. and in energy usage - I was very pleased, and amazed.

I could not find what I thought was near enough to an ideal (fan) heater, so made some. The cloche has 2, running at 250W, but switchable to 500W if the weather gets very cold. The fans run so long as the greenhouse temperature is below 6C, in other words, always circulating when the weather is cold. The fans run at ~20W.

Page 4, towards the top of the RH column -

"There have been no reports of it becoming problematic in the wild"

Quote from: Robert_Parks on December 10, 2023, 07:38:24 AMPresumably G. tinctoria is already banned?

Yes, banned a few years ago, hence my comment about worst case parent.

If you look at the "logic" of the whole thing, it is being banned because it is a hybrid of a banned species, no other reason. Maybe somewhere down in SW England, or somewhere very close to the coast in the W of Scotland (which actually has a very mild climate over large parts due to it getting "hit" by the Gulf Stream), there are large stands of the plant outside of gardens and parks, "feral"?

I have lived in S Devon and W Scotland, and saw no evidence of any problems.

Quote from: janemcgary on December 09, 2023, 04:10:05 PMInteresting that they use an English name "giant rhubarb."

I don't think that I have ever heard anyone with any kind of gardening interest or knowledge use the name in the UK - it is always called Gunnera.

Otherwise, I suppose it is an obvious common name to pick.

Quite why there is now this hue and cry about it is difficult to understand. Apart from Paignton Zoo, I have never seen anything but (very) modest clumps and in most of the UK it needs to be buried under plenty of straw each winter to protect againgst anything but very mild frosts.

Quote from: David Pilling on December 09, 2023, 03:53:54 AMPopular garden plant BANNED after it turns out to be rapid-spreading invasive species

True to a point, apparently. Mentioned on GQT? Somewhere on R4 for sure.

Apparently someone checked the genes of a lot of different Gunnera in the UK and the great majority is a hybrid (details of the other partner, apart from true G. manicata, will be found online somewhere....). The non-mannicata species was already banned, but the principal with hybrid anything is that the hybrid assumes the position of the "worst case" parent.

It really is total nonsense. Whatever the plant is or is not in the UK, it is borderline hardy once you get away from warm coastal areas and the SW.

The plant will not have to be removed from UK gardens, but propagation and sale are now illegal, unless you can prove that the plant is not a hybrid, but genuine mannicata.

I have no idea if it is still there, but there was a Gunnera "forest" around the lake in Paignton Zoo - very, very impressive.

I haven't searched for any of the papers mentioned above, but very many can be accessed for free via this portal (the paper linked to happens to be the one that most recently appeared in my inbox - two days ago, a paper about Amazon lillies by Meerow appeared - some coincedence!!). You do have to register, but that is simple.

Papers that I receive may not be new - I have no idea what determines exactly what is sent, except the broad selection of topics that I chose.

Martínez-Azorín, M., Clark, V.R., Crespo, M.B., Dold, A.P. & Barker, N.P. (2011). The rediscovery of Albuca tenuifolia, an orophilous species from the eastern Great Escarpment in South Africa. Nordic Journal of Botany 29: 465-470. | Nigel Barker - Academia.edu

Just found this - new(ish), and not the one that I have watched before, which was filmed in Japan

A mention in the video - that it is a brassica - reminded me of something we did as kids....... After any brassica had been cut in the garden, we would get the knife and cut the white pith from the inside of the stem, and eat that raw. It can be quite hot but otherwise it has a typical "raw cabbage" taste. You could get an awful lot from a sprout stem!!
It did/does have one unfortunate effect though - gas, and lots of it!!!

Quote from: janemcgary on December 03, 2023, 06:22:11 PMFor a long time, Japanese experts claimed that wasabi could not be grown anywhere else. Recently, however, it has begun to be grown in Oregon. I don't know if it's in actual streamflow, which would be possible near the Pacific coast where the grower is, or whether it's in a hoop house with circulating pumps, but yes, it's aquatic. It has not, to my knowledge, been used here as in Japan, see photo of ice cream shop.

For sure the rumours are that true wasabi is difficult to grow, not so much linked specifically to Japan, but the growing conditions required to get a good crop of good wasabi. Given the price, I suspect that there must be at least some element of truth in that as the price would drive people to try.
The only video that I have watched of a Japanese wasabi "farm" has shown shaded fast-running streams. I seem to recall water temperature being mentioned as important too.

Quote from: Ron on December 03, 2023, 07:57:48 AMI have heard that there is very little true wasabi in sushi bars in the US.  It is supposed to be horseradish dyed green.

Maybe in the US too? But horseradish is native to the UK - a roadside weed. Very occasionally you will see people digging the roots, but it is farmed on a very small scale, for manufacturing horseradish sauce - probably the more traditional, perhaps more popular, accompaniment to roast beef in the UK.
To get the right heat v. flavour the commercial producers use a particular ratio of main root (around 10-20mm diameter) and finer feeder roots that grow off the main root.

Cold roast beef and horseradish sauce sandwiches...mmmmmmmmmmmmmmmmmm

As above, the problem is with the website - it is always falling over.

This time it "lost" my order and two messages, all sent different times.

A quick look back through emails and it has done similar things before........................

Everybody, just beware.

Following @Uli's suggestion on the Lanaria thread, I invested in a packet of mycorhizal fungi/bacteria treatment, sold for improving performance of cuttings. It was a semi-random choice as I have never used anything similar previously - semi-random insofar as it was the cheapest available   

I was surprised when it arrived last Friday - fine grit, mixed size from fine sand to maybe 2mm across.

I ground a pinch of it into 5-10ml of tap water and threw that into the top of the 8cm pot of Xerophyta seedlings.
Today several of the ~30 seedlings are showing a third (first real) leaf (a lens is needed to see them currently)!!!! None got that far in the previous batch, so I have all fingers crossed.

Well, it took over a day for Ondine to answer, but it looks like the Silverhill website has been compromised or somehow failed again.

I have to resubmit the order via the webiste and as insurance, by email as well.

Bang goes plans for receiving the seeds before December/Christmas.

Quote from: MarkMazer on November 27, 2023, 11:08:54 AMThey sent a notice out several weeks ago that they would close for the holiday season. I'd try again in January.

Yes, I received it here and the last date for shipping orders was/is 1st? 2nd? week in December (I can't be bothered looking it up, although Uli's post above contains all anyone needs..). Closing for Christmas in the 1st/2nd week of November would be very odd indeed.

I am also unsure why that would lead to deletion of my order from the website after it had sat there and been updated with postage costs for around 2 weeks, and been replaced by an ancient order that was not there in my order history previously....................

With the order deleted, I can't be sure when I placed it, but I looked up dates beforehand and had plenty of time.

It looks like Silverhill may be having problems.................

I placed an order about 2 weeks ago and have been waiting for a postage quote, which appeared on the order on the wesite towards the end of last week.

I contacted them twice via their online form, once to ask about the delay in a quote for postage and once to ask why the total cost, including postage, had not been raised as an invoice and sent via email.

Neither was answered.

Today, the order has completely disappeared from my account, replaced by one that I placed nearly three years ago. I have now sent an email direct, rather than via the website.