PBS Forum

Quote from: David Pilling on December 28, 2023, 02:07:58 PMAll 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.

Think really BIG - like Star Trek Big!  Is there enough gold in the solar system perhaps?

Have any of you rock gardeners or alpine plant enthusiasts every grown Carlina acaulis from seed?  It's a neat looking plant - and that saying a lot for a thistle! They flowers are large and impressive for such a plant.

Anyway, I have some seeds and have tried a few times to get them to germinate without success.  One website suggests that cold stratification for 60 days may do the trick.  So, I'm taking their advice and I'll either sow the seeds a pot and place them in the fridge for 2 months, or place the pot outside on the patio while the temps are above freezing.

Or, should I put them in the freezer for 60 days or keep them outside even if the temps fall below freezing?

I hope I just don't have old seed.  But, when I look at the seeds on moist soil under a loupe, they are plump, covered with fine erect hairs, and look quite happy - they just won't germinate.

Thanks much!

Quote from: David Pilling on December 24, 2023, 07:56:41 AMI 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.

Think really big - how about an Avogadro's number (mol) in gold krugerrands!

Quote from: Bern on December 28, 2023, 11:04:52 AMApogee Full-Spectrum Quantum Sensor

A steal at $532.00

https://www.apogeeinstruments.com/quantum/

Probably the best available at the price. 

Quote from: CG100 on December 24, 2023, 07:24:00 AMI can only find one - VERY expensive - a Hortipower PG200N.

Only $3388.00!

https://gamma-sci.com/product/pg200n-handheld-par-meter/

Quote from: CG100 on December 26, 2023, 01:22:24 PMBe very careful if looking at buying cheap PAR meters.
Many, perhaps most or all, are not.

Caveat emptor! Let the buyer beware. Excellent advice.  Kelly uses the Apogee Full-Spectrum Quantum Sensor and I will take a close look at that one.  I think you also posted a link to one and I will take a look at it also.  Thanks!

Quote from: Robert_Parks on December 25, 2023, 09:17:35 AMI have a PAR meter (~US$150?) that I use to check lighting for the indoor bulbs[1]. Also, to verify outdoor lighting situations.

I do not use it at a level (accuracy, consistency, etc) to justify the price, but it does do the job in a handy package. What it does do is let me track and reproduce what individual species prefer or tolerate in my conditions. Interesting sometimes just how little light some forest floor plants want, compared to fall sun!

[1] Irresistible geophyte aroids that tolerate my (even indoors) cool tropical conditions.

Hi Robert. It's good to hear feedback from an actual user of a PAR meter.  I'm going to purchase one of these things as I've been convinced by Kelly's articles that it's a worthwhile gadget. I have a lux meter, but I don't want to mess around converting lux to PPFD.  Kelly uses the Apogee Full-Spectrum Quantum Sensor which cost her $500 in her 2021 article. What make and model do you have? Yours is quite a bit less expensive than Kelly's and it may be AOK for what I need it for.  I'm going to be growing a lot more of my plants under lights and I'm going to try to construct an ochidarium for some of the miniature Dendrobium and "leafless" orchids that need to be mounted to grow properly.  They need the right amount of light, temperature, and humidity and I don't want to kill a bunch of expensive plants guessing on their light requirements. Temperature and humidity are much easier to measure.

Did you have any success germinating JAA's Albuca unifoliata seeds?

Quote from: CG100 on December 24, 2023, 07:24:00 AMUse a cheap luxmeter and the simple conversion as above

Kelly discusses the conversion factor from lux to PPFD in her third article. Kelly appears to have a fine technical background and she knows her subject matter.  She is a woman that is worth listening to and her articles are worth reading. 

If I remember from the List there are PBS members who own PAR meters and are using them. It would be great to hear about their experiences with them.  I'm thinking about purchasing one and it would be helpful to know more about them from a person currently using one.

Is anyone using a PAR meter to measure lighting for their plants?  If so, would you please tell us the make and model of the meter you are using and how you think it is working for you?  And would you recommend the meter that you are using or would you recommend a different model?

Quote from: CG100 on December 24, 2023, 12:38:05 AMOne thing that did surprise me is that amounts of light are now routinely quoted in moles (mols) within horticulture.

This was one of the biggest surprises for me in Kelly's articles.  I'm used to the concept of moles in chemistry, but I had never encountered it in regards to lighting. The use of Avogadro's number (6.022 x 10²³⁾ to quantify photons was a new concept to me.  This advance coupled with the development of sensors that can quantify the photons in the photosynthetically active parts (PAR) of the electromagnetic spectrum and then give you a readout on a PAR meter in µmols per square meter appear to me to be a real advance in understanding.

Kelly addresses most of the points you make in her articles.  You may find them "illuminating."

Kelly's articles are written in such a way that a layman can gain much useful knowledge about using some of these advanced techniques to better understand artificial lighting for plants.  The articles are not written exclusively for technical specialists.  So I encourage everyone who is interested in this subject to take a look at her articles.  She gained and deployed this knowledge in an experiential way to start a successful orchid business in an arid environment that one would normally consider unsuitable for growing this type of plant.  Succulents yes, orchids no.

And keep an open mind about what you read. We can make advancements going forward from this initial vantage point.

Quote from: petershaw on December 16, 2023, 06:43:10 AMAlways looking for new ideas on heating and retaining heat even in my "mild" climate and solar panels.

Quote from: David Pilling on December 16, 2023, 09:33:49 AMReally how to heat your greenhouse is an interesting subject, one that has been touched upon over the years in the PBS list and worthy of discussion.

I propose renaming this post as Greenhouse Discussions Only and moving it to General Plants and Gardening.  Is that OK with you Peter?  And David, if it is OK and worthwhile, can it be done without too much ado?  The Heating Your Greenhouse posts can then continue as is and ad hoc. 

There were many great posts to the PBS List about artificial lighting. Now we have a place to post and discuss that topic on the Forum.  I'll begin by listing some reference articles on LED lighting that were published in Orchids Magazine and were written by Kelly McCracken, who had a successful orchid growing business in Albuquerque, New Mexico.  Kelly was able to grow and propagate orchids with low, medium, or high light requirements under LED lights in an otherwise unlighted warehouse at 5000 feet in elevation in an arid environment.  This is an impressive accomplishment and it highlights the potential of artificial lighting for plants, especially LED lights. Kelly makes a convincing and evidence based case for using a PAR meter (Photosynthetic Active Radiation) to adjust the PPFD (Photosynthetic Photon Flux Density) for the type of plant you are growing.  Apparently, some LED fixtures available today are even dimmable.  PAR meters are pricey, but you get exact information that you can use and you don't have to guess how much red or blue light you need, what is the exact Kelvin rating of the lights you have, or endlessly adjust the height of the shelves for your plants.

You can obtain copies of these articles by asking your local public library to provide you with a pdf copy. After you obtain your copy, you can combine them into one file with a pdf editor.  Free pdf editors are available online. The final document will be about 12 pages long with a file size of approximately 18 mb.

2021/07 July ORCHIDS Magazine
·An Introduction to PAR and PPFD - Why You Should Forget Lumens: Part 1 of a Five Part Series on Light
 
2021/08 August ORCHIDS Magazine
·Let There Be Light! - Target PPFD for Orchids and Tropical Plants: Part 2
 
2021/09 September ORCHIDS Magazine
·Let There be Light - Part 3: Measuring Artificial Light Without a Quantum PAR Meter
 
2021/10 October ORCHIDS Magazine
·Let There Be Light - Part 4: Setting up Your LED Lights
 
2021/11 November ORCHIDS Magazine
·Let There be Light - Part 5: Spectrum and Photoperiod

The WWI Christmas Truce in 1914

"The Christmas truce was a series of widespread unofficial ceasefires along the Western Front of the First World War around Christmas 1914. The truce occurred five months after hostilities had begun. Soldiers along the western front broke into spontaneous truces of Christmas celebration, song and even exchange of gifts. For a brief moment they wondered why they were juxtaposed in lethal combat along the jaws of hell." Sadly, the war would continue for almost 4 more years.

"British Field Artillery Lieutenant John Wedderburn-Maxwell described the event as "probably the most extraordinary event of the whole war – a soldier's truce without any higher sanction by officers and generals....""

"numerous accounts in letters and journals attest to the fact that on Christmas 1914, German and English soldiers played soccer on the frozen turf of No Man's Land."

A detailed account of this event by Will Grigg is detailed here.

https://fee.org/articles/the-christmas-truce-of-world-war-i

I'm hoping for a Christmas truce this 2023 and that it will extend well into the coming years.  It can be done.

Merry Christmas to All!

The winter solstice is fast approaching, marking the official beginning of winter with the shortest day of the year. The Royal Observatory in Greenwich marks the actual moment of the solstice in 2023 on December 22nd at 3:27am GMT in the UK. Dr. Google marks the time in the USA at 10:27 PM EST on December 21st. Around the world, many people will be visiting various archeoastronomy sites to witness the event. The Druids and Pagans should be well represented at Stonehenge this year.

https://www.rmg.co.uk/stories/topics/when-winter-solstice-shortest-day

Cheer up, the days get longer from here for another six months!

Quote from: David Pilling on December 15, 2023, 04:04:25 AMthere does not seem to be much to laugh about anymore. Might be to do with getting older.

Very true, but it is best to keep trying.........

Q: How do you fit 4 elephants in a Volkwagen Beetle?
A: Put two in the front and 2 in the back.

Problem solved.  A bit of efficiency that Germany is renowned for perhaps?

And on another note - the Christmas shopping rush is upon us and the stores are packed with shoppers. Every store is playing the same annoying holiday music.  It seems that everywhere you go it's the same Dolly Parton song over and over again.  By the time you get home it's stuck in your head for a few hours. 

Finally, today is the local caged bird club's annual Christmas party and everyone will have a very enjoyable time.  Earlier this year I had to amend the club's bylaws to prohibit the open carry of handguns at the monthly meetings because it was disconcerting to many members.  There will always be members with concealed handguns at club functions, but that cannot be prevented.  'Tis the season......................

You just have to laugh it off.........