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CG100 - good to see actual calculations. In the old days I used to put buckets of hot water in the greenhouse at night. Now I see I was probably wasting my time.

My problem is slightly different, I am only trying to keep temperatures above freezing. I like to kid myself that what matters is the latent heat of fusion not the specific heat capacity (SHC). In other words a lot of energy changes hands when water freezes. Latent hear 333.2 kJ/kg against SHC 4.2 kJ/kg.

So by packing my greenhouse with plants (soil, water) I can postpone freezing, I only have to do that for a few hours.

We've all heard of the 'greenhouse effect' - radiation goes in, but can't at a different wavelength get out. That's why it is so hot.

Similar placebo effect, I run an oil lamp, I read that there is 10kWh of energy per litre of paraffin/kerosene (CG100 you said 12 for diesel). However I burn a lot less than 1 litre per night - a quarter maybe.

I always wanted to set up a fan to move air between the top and the bottom of the greenhouse. In the day time the top is hot and the bottom cold. At night the situation reverses. Damage from cold will start at the top and work its way down - put the tenderest plants on the lowest shelves.

Possibly not all in my imagination, since I monitor the temperatures in heated and unheated greenhouses and the lamp does make a difference.

Diane - nice narcissus. Rather a long time to wait.

This far North one has to be grateful for what there is. Spring bulbs are making progress, perhaps because it has not been very cold.

Photo 1, a spring flowering crocus.
Photo 2,3, kniphofia Christmas Cheer
Photo 4, Ipheon
Photo 5, daffodils coming through

I liked (but never tried) the idea of putting seeds, that need chemicals washing out to germinate, in a muslin bag in a toilet cistern - thus being exposed to random wetting and drying.

I germinated all my seeds in zip lock bags, I'm not denying that exposure to the elements in general might help, it just never applied to me - when I say real Winter is better than a fridge, that's a zip lock bag left in the garage, which would never get below zero.

Temperatures in fridges are not always what you might expect (warmer in the door). It was always the sort of dream spun by seed vendors "four weeks in a fridge to germinate".

My favourite guide to seed germination is on the Ontario Rock garden society web site, it says for Carlina acaulis:

"Sow @ 20°C. Seed germinates within 3 months Requires light or the seed is very fine. Surface sow and expose to light."

https://onrockgarden.com/index.php/germination-guide/germination-guide


The PBS wiki has a list of sources on how to germinate seeds:

https://www.pacificbulbsociety.org/pbswiki/index.php/HowToGrowBulbsFromSeed


I used to spend a lot of time germinating seed, my conclusion sticking things in the fridge was never as effective as real Winter (putting them outside).

Quote from: Bern on December 28, 2023, 03:43:01 PMIs there enough gold in the solar system perhaps?

"
there is gold in the sun. The sun is a "metal rich" Type I star (that's "rich" by star standards, about 2% of atoms that are neither hydrogen nor helium).

the abundance of gold is about .3 parts per trillion. That comes to about 10^20 kilograms of gold.
"

I'll give you that the Sun contains a mole of Krugerrands - now how do we get hold of them.

Quote from: Bern on December 28, 2023, 11:20:59 AMThink really big - how about an Avogadro's number (mol) in gold krugerrands!

All the gold in the world 244 000 metric tonnes. One Krugerrand 33.9 gm. Max possible Krugerrands 7 197 640 117 - nowhere near a molesworth of them.

Quote from: CG100 on December 28, 2023, 03:50:30 AMApparently world production is around 300 tonnes per annum

That's about 150 million flowers, perhaps enough to see from space but a long way short of a mole of flowers.

This is the one sign to tell if someone is 'drowning in money' - and it's found in their kitchen

A young woman has revealed a fool-proof way to tell if someone is extremely wealthy simply by looking in their kitchen.

Zoya Biglary, a food entrepreneur from the US, proudly showed off the massive jar of saffron she uses sparingly when cooking.

Australia produces 10kg of saffron annually and imports around 3,500kg of the spice from Spain and Iran each year.

... it takes 150 flowers to produce one gram of dried saffron

https://www.dailymail.co.uk/femail/food/article-12902707/Saffron-Australia-price-wealthy-kitchen.html

Here is the whole list of plants discussed in the General Discussion.

The list marked Posts are the original letters, and Replies are the letters replying to those posts.  Sometimes a post did not get any replies at all, but some received many.  The original letter about Resnova inspired 14 people to respond.

Genus            Posts      Replies
Albuca              2          5
Allium              1          0
Amarine            1          10
Amorphophallus 2          13
Arisaema          2            2   
Asparagales      1            1
Bessera            2            9
Biarum            1            6
Boophone        3            1
Caladium          2            3
Calochortus      3            14
Colchicum        2            20
Crinum            2            10
Crocus            4            11
Cyclamen        1            4
Cyrtanthus      2            8
Diplarrena        1            0
Dracunculus      1            8
Erythronium      2            6
Eucrosia            2            2
Ferraria            1            2
Fritillaria            3            3
Gesneriads        1            0
Gethyllis            2            2
Gladiolus          4              8
Gloriosa            1            8
Habranthus        2              2   
Haemanthus      2            21
Hippeastrum      2              8
Hymenocallis      2              6
Hypseocharis      1              5
Ipomoea            1              2
Iris                    3              1 
Kniphofia            3              5
Lanaria              1            11
Lapeirousia        1              1
Ledebouria          1              4
Leucocoryne        1              4
Lilium                3              27
Milla                  1              1
Mirabilis              2              7
Moraea                1              10
Nerine                5              25 
Notholirion          1              3
Ornithogalum      1              1
Oxalis                  5              34
Parakeelya          1              10
Paramongaia        1              11
Pasithea              2                2
Pelargonium        1                6
Phaedranassa      1                0
Pterocactus          1                0
Puschkinia            1                2
Ranunculaceae      1                3
Resnova                1              14
Rhodophiala          4              18
Sarracenia            1              8
Scadoxus              1              1
Scilla                    3              11 
Scoliopus              1                4
Sprekelia                1              1
Sternbergia            1              0
Trachyandra            1                0
Trillium                  1                4
Triteleia                  1                4
Tulbaghia                1                0
Tulipa                    2                5
Watsonia                2                2
Xerophyta              1              2
Zantedeschia          2              1
Zephyranthes          2              11

Hmm.  Now I see that Nerine tied with Lilium for second most popular, with 30 total posts.

Quote from: CG100 on December 24, 2023, 07:24:00 AMAt the end of the day a mole (mol) is just a number

I wish someone had told me that when I was 16 and doing A level Physics - a mole of football supporters would have been a very enlightening concept.

Seemingly Mr Avogadro never knew his number, much less application to photons.

Quote from: CG100 on December 24, 2023, 04:14:16 AMAmaryllidacae?

Oddly that is the most popular page on the PBS wiki, despite not having any photos on, it's just oranisational glue.

I would guess Lilium because they're popular, but that may mean there are plenty of places to talk about them.

They were more sporting at the start of WW1. My great uncle Jack was captain of a merchant ship off South America, in 1914 it was sunk by SMS Leipzig, but first he and the crew were taken off and eventually deposited on land, uncle Jack receiving a gift from the captain of the German cruiser.

For his part, he did not rejoin the war, having been freed, but set up the local nautical college.

Quote from: Bern on December 23, 2023, 01:41:37 PMMerry Christmas to All!

'God bless us, everyone' said Tiny Tim.

It is true that people say K and not Kelvin. But do they say H or Hertz. N or Newton.

Commonly people talk of kilo Watt hours 'units' not Joules. Would be interesting to put food (Calories (a metric but non-SI unit)) in the same units as battery capacities (Amp hours (x Volts)) and that unit would be the Joule.

Could link all this with plants, the common names or the long since botanical names stick around after the professionals have set the world to rights and moved on.

Lets hear it for the BTU (British Thermal Unit, 'therm'), the horsepower hour and gasoline gallon equivalent.

The Centigrade scale existed and was in use before Kelvins were invented... that'd be when I was a lad in the 1960's.

Actually the Kelvin scale was proposed by William Thompson in 1848, but the Kelvin scale was only standardised and named in 1954.

So pre 1954 people measured differences in degrees C.

Mr Celsius invented his scale in 1742, but outside of Sweden it was called the centigrade scale until 1948.

In the 1960's it was commonly still called centigrade and we struggled to come to terms with cycles per second becoming Hertz.

5-bob on them dropping the blokes' names from units and just going with letters at some point?

If you're measuring in °C then why wouldn't differences be in °C. You have a thermometer it shows XX°C - so you'd write in your notebook values in °C and then take the difference.

As a child I had Imperial units beaten in to me (literally), I was sat at a desk for the first five years of my education memorizing how many furlongs in a mile, chains in a furlong, pennies in a pound, fluid ounces etc. Anyway this education made me what I am, and I measure temperatures above freezing in °F and temperatures below freezing in °C.

We did hear tales that in Germany they used °K, but surely you'd say your plants freeze below 273 °K. You're in a transitional state and one day people will say "it's a fine day, the temperature is 293 °K".

I had more luck with my Physics career, only the first three months (at age 14) used the cgs system (dynes, ergs) and the rest of it was MKS.

I curse the fools who decided the UK would go metric, they doomed us to a 100 years or more of confusion. All the doors in this house are Imperial size as are all the bolts and screws. I have a workshop full of Imperial tools. We have mysterious units in the shops, why are things sold in 453gm packets (because it is 1 pound weight).

Good luck to the USA in keeping the old units.

It's not as if broad and sunny uplands where everyone uses the same units lie ahead. People are tinkering with the definition of a kilo-byte as 1024 bytes (the latter is now properly a kibibyte).