growing plants with reflected light

[philbobaggins]

Howdi forum,
Some friends and I are thinking of making a garden in a space 4 meters lower than street level.
As you can imagine most of it only gets the sun around midday, and some parts actually never see the sun.
We could just put in a bunch of shade-loving plants but would like to experiment using reflective surfaces ie. white paint, mylar, mirrors, and would love to be able to grow a heap of veggies. I would appreciate any information you may have on growing plants with reflective light. Your advise is much appreciated!
Thanks,
Philbo

[thepoolroom]

I don't have any info or advice to offer, but it sounds fascinating! I'd love to read more about what you discover.

[Hamishmac]

Hi Philbo,

Before and after pics would be great. I always forget the before pics :? .

Water feature and white pebbles as mulch come to mind, in theory anyway. Or...could you connect the two? A version of backyard aquaponics using white pebbles on the surface instead of expanded clay pellets?

http://www.backyardaquaponics.com.au/

What sort of area have you got, and where?

Hamish

[philbobaggins]

Thanks for your comments.
The site is a basement courtyard of 32 sq. meters and is located at the Tokyo museum of modern art.
You can look down on the space from the main lobby of the museum.
Its a great opportunity to showcase permaculture in action, but the light restrictions are great. We are thinking of using mylar or some other highly reflective surfaces to drape the interior walls for increased solar exposure but have no previous experience in this area. Any advise further advise would be great.
Thanks for reading this post!

[Hamishmac]

Hi there PB,

sounds like you've got a challenge on your hands. Does the "garden" at least face South, or is the building in the way? Once you're at a higher latitude than the tropics (23.5 degrees) the sun will never truly be directly overhead, even at midday on midsummer's day.

http://susdesign.com/sunangle/

is a calculator where you can see how much (or little) direct sunlight will scrape into your garden in Tokyo's 35 deg latitude, and might help with planning placement of reflectors.

Could you use direct sun to hit some solar panels on the museum roof, and use the collected energy to power some grow bulbs in the veggie patch :? . Or is that cheating?

Hamish

[Michaelangelica]

This is something that interests me as I have a large, too-shady garden. Designed by a blind architect I still can't work out which way it faces!
Mirrors decompose and are no longer made with the excellent, long lasting, toxic mercury
Any suggestions on a inexpensive, mirror-like, reflective surface that will survive NSW Australia sun, please let me know.

There are light tunnels being used in some green buildings (Israel?) which might give you some ideas.
They take sun- light from the roof down several stories of office.
For a house
http://en.wikipedia.org/wiki/Light_tube
http://www.reuk.co.uk/Light-Tubes-for-I ... ghting.htm
Some possibilities here??
http://en.wikipedia.org/wiki/Daylightin ... r_Lighting
Geeks talking about tubes
http://www.physicsforums.com/showthread.php?t=164959

this is the closes I could find on what i was looking for. Googling those words might help?

offices on the interior enjoy indirect light from strategically located heliostats, mirrors, and reflective surfaces that bounce light throughout the atrium.

http://www.architectureweek.com/2005/02 ... t_1-2.html

i did that and found this

Light tubes

Light tubes or light pipes are used for transporting or distributing natural or artificial light. In their application to daylighting, they are also called solar tubes, solar pipes, daylight pipes, or solar light pipes.
Generally speaking, a light pipe or light tube may refer to:

a tube or pipe for transport of light to another location, minimizing the loss of light;
a transparent tube or pipe for distribution of light over its length, either for equal distribution along the entire length (see also sulfur lamp) or for controlled light leakage.


[b]Light tube with reflective material/[b]

Also known as a 'tubular skylight', this is the oldest and most widespread type of light tube used for daylighting.
A round tube lined with highly reflective material leads the light rays through a building, starting from an entrance-point located on its roof or one of its outer walls. A light tube is not intended for imaging (in contrast to a periscope, for example), thus image distortions pose no problem.

The entrance point usually comprises a dome (cupula), or alternatively a diamond-shaped light collector, which has the function of collecting and reflecting as much sunlight as possible into the tube.

Light transmssion efficiency is greatest if the tube is short and straight. In longer, angled, or flexible tubes, part of the light intensity is lost. To minimize losses, a high reflectivity of the tube lining is crucial; manufacturers claim reflectivities of their materials, in the visible range, of up to 98 to almost 99.5 percent.

At the end point (the point of use), a diffuser spreads the light into the room.

To further optimize the use of solar light, a heliostat can be installed which tracks the movement of the sun, thereby directing sunlight into the light tube at all times of the day as far as the surroundings´ limitations allow, possibly with additional mirrors or other reflective elements that influence the light path. The heliostat can be set to capture moonlight at night.

http://www.worldofrenewables.com/page.php?pageid=31

This article is hard to read. English is obviously not the author's strong suit.
http://www.learn.londonmet.ac.uk/packag ... ec2002.pdf

How to build a heliostat for solar heating and lighting
http://www.iwilltry.org/w/index.php?tit ... d_lighting

Abstract
Tubular daylight guidance systems are linear devices that channel daylight into the core of a building. They consist of a light transport section with, at the outer end, some device for capturing natural light and, at the inner end, a means of distributing the light within the interior. This technology is examined in terms of performance, cost, design issues and governance (codes) for the different generic types of systems.

http://www.informaworld.com/smpp/conten ... 027~db=all

OK that's taken me an hour and I haven't solved my problem, or yours.

Here are more words for you to google
Keywords: alternative technologies; daylighting; energy; guidance systems; heliostats; lighting; tubular light pipes; technologies alternatives; lumiegravere du jour; eacutenergie; systegravemes de guidage; heacuteliostats; conduits tubulaires de lumiegravere, Solar energy; illumination by solar radiation; sunlighting; thermal and visual comfort; daylighting;
renewable energy; CO2 reduction; sustainability, hollow light guide, liquid fiber optics.

[philbobaggins]

Wow! I just wanted to send an immediate THANK YOU!!! and will get back after I`ve been through all the information.
I can`t tell you how timely this infusion of information is!

[ultradeluxe]

thank you for all your comments

here are some "before" photos of the space http://web.mac.com/namaiki/iPhoto/mot-g ... /index.rss - not sure if you can all read this rss link - apologies if you can't

thanks also for the sun angle calculator link, the garden is south facing, approx 4 m underground and has a tall glass wall on its north side, this is a rough look at the sun angles for the site http://docs.google.com/Doc?id=dmgkq9x_74cswfkjdp

love the idea of some aquaponics ...

will keep you posted with some "during" and "after" photos too !!

michael

[barely run]

Hydrophonic growers of illegal plants in Aust have used fluresent lights indoors with no outside natural
lighting and had sucessful crops. perhaps the same ideas would work for legal plants in your low light setting.
cathy

[raincrow]

I keep coming back to this thread and wondering "what is growing there now?" Any plants at all? Moss, lichen, fungi? Is the floor of the space soil or concrete? I know growing veggies is exciting, but isn't permaculture also about using a space for what it is best suited for? What were the understory plants that grew on the site before the building was built? What about a water feature with moss covered boulders, running water, ferns and fungi? Harvesting edible fungi would be exciting also. Is there a rare salamander in the area that this site could become a sanctuary for? Moss, lichen, and fungi are a huge part of life on this planet and the variety is astounding and beautiful.
My wife just read over my shoulder and added that it might be a great site for wasabi and ginger [with her mouth watering]
If you are going to use plants that require lots of light, remember that they also will need the humidity variations, temperature and air circulation that a sunny location would provide. cheers