What Colour Shade Cloth Is Best?

[baphomet]

I was just speaking to a shadecloth wholesaler who says that different coloured shadecloth filters out different parts of the spectrum and makes a big difference with some plants, this is news to me, I thought it was just a matter of personal preference. Apparently cucumber farmers only use blue, some farmers only use black for ferns and other trees cause it makes them grow taller and white is used by fruit/tomato growers to get bushier more productive plants.

Anyone know what colour is best for the plants like caapi, viridis, certain species of salvia, etc?

I know this is an odd question but if anyone has any info it would be greatly appreciated.

Thanks.

[Torsten]

the basic principle is that you don't want to deprive your plant of the colour light it needs. As such green is probably the worst choice for most plants and I never understood why this is the default colour. But anyway.... plants are green, so this is the colour light that is reflected from the leaves, ie not used.

if cucumber farmers use blue then they are giving the plants less yellow, red and green, but more blue. Blue light is usually used for vegetative growth, which is why that phase can also be grown in MH or fluoro lights.

white shadecloth would provide more of everything.

black shadecloth would provide less of everything.

brown reflects a lot of reds, so good for flowering or fruiting plants usually [same reason why HPS lights are used for this phase].

I could be wrong, but that's the logical way to look at it.

[baphomet]

That's quite valuable information, thanks (I bet there's a lot of people out there kicking themselves for buying green shade cloth )

[~shameless~]

Just from my observations from looking at wholesale and specialist nurseries also looking through books on some plants i notice white and biege type colours bieng used heaps, a nursery i worked at ( beding palnts and seedlings) had white shade cloth too,

Just that i'v noticed, i havent read that anywhere!!

Thats cool torsten, i just built one (shade house) and guess which colour i used!! haha just for looks. my best shade house is in white coincidentaly enough though.

[watertrade]

That's quite valuable information, thanks (I bet there's a lot of people out there kicking themselves for buying green shade cloth )

yeah..... ;) I have my greenhouse partially covered with a 50% shade cloth - letting the Trichocereus have a fair bit of sun and more shade on the Astrophytum, Lophs and others. I would really like to get hold of a lighter ~20% shade? for some reason i want to provide some protection....

[Torsten]

shade cloth decreases shading capacity over time, so maybe just use older cloth or stretch it more.

[Vertmorpheus]

"green is probably the worst choice for most plants and I never understood why this is the default colour" - T

haha, true that! I think there's a couple reasons people started using it, why it became the norm I have no clue.

I think the first people using em especially domestically were right into things like broms, ferns, epiphytes, things that live under a dark green canopy anyway and so are after that reddish spectrum but lower lumens in general. People had a visit to those places, and nurseries especially made big use of it for a combination of spectrum and of course just looks... then people took that idea and look HOME, even if it was less than relevant. Seems to have travelled along the same routes as "aussie gardening chestnuts" (macadamias?) like "all aussie soil needs heap of dolomite" "cactus need full sun" and "pinching laterals promotes a more productive tomato plant"... case sensitive advice applied in a widespread way.

Course, you have to get into density too, a 50 percent green cloth might just let in more useable light overall for your particular mixed crop (lumens and spectrum), than a piece of 90 percent brown cloth (no idea, I do have the charts here somewhere, being purely illustrative).

Where I'm at, almost anything that just knocks half the strength out of the 10-2 peak heat n light period is good enough, there is simply too much light for most things and they just stress out for half the day....as long as it doesnt block too much light out either side of that... but then I have seen a lot of very nice sub/tropicals grown under heavy green cloth usually covered in leafdrop from sheltering eucas, too. Especially forest floor things, etc.

Problem there, if you want to grow rainforest TREES under green, is that they will stretch to bullshit and never take advantage of the "full sun, short bushy tree" phenomena seen with a lot of rainforest species... but if you wanted nice established specimens maybe you could put em under green for a bit to get the height up, then under more of a red/brown spectrum to make it think it has "broken the canopy".

Green leafies under dense green cover get the feeble stretchies, more so in overcast periods.

best overall results (around here, anyway) are from black, 70 percent or so, palms n tropicals go nuts, clear plastic for plants that like it really muggy, with occasional (seasonal) applications of chalk wash so you get soft light in the bright part of the year, and lots of direct light with a frost protection air bubble in place for cold times. Depends how fiddly u want to get, or what scale you're talking. A blackhouse and a whitehouse seem to do a lot of people fine, start in the white and harden in the black typically.

Some ppl have good results with things like lattice, vines, meshes etc, anything to break the light but not necessarily filter spectrum any.

I don't know if there is one "best" colour, but I'd say build two areas, one with black and one with a light green/brown, then you can juggle around til things seem cheerful. You can see green things very clearly thru it, though. Depends how intrepid neighbourhood kids are I guess

VM

[Micromegas]

That's very interesting torsten.

However, this might be a stupid question, but if green plants reflect green light, how come a green shade cloth lets in green light. I thought objects are the colour they are because that is the colour they are reflecting. Thus, isn't a green shade cloth reflecting green light, rather than letting it through?

[planthelper]

That's very interesting torsten.

However, this might be a stupid question, but if green plants reflect green light, how come a green shade cloth lets in green light. I thought objects are the colour they are because that is the colour they are reflecting. Thus, isn't a green shade cloth reflecting green light, rather than letting it through?

i see it aswell like you micromegas...

i think green shade cloth is allright because it would reflect mostly green light and plants dont need that part of the spectrum anyway.

another thought is that, a forest basicly constitutes a giant green shade cloth and i doubt nature would have made a mistake with this concept. in other words, the plants at the bottom might recieve only very low light levels, but i doubt that the red and blue aspects of the spectrum would have been reduced proportionally to a higher degree than the overall spectrum.

so red and blue shade cloth would have to be the worst.

[incognito]

id go indigo if such a colour is available in shade-cloth.

thats the spectrum most used by plants for growth (if i remember correctly)

[Mr Stay Puft]

You would want to be using something in the 50% UV block out range. Colour will not make a huge difference, although lighter colours allow greater amounts of light to pass than darker ones.

At the bot gardens we had black shade cloth and i can assure it did not effect growth at all, has more to do with density, and the average is 70% which is getting towards that too much absorption rating.

[kadakuda]

i see it aswell like you micromegas...

i think green shade cloth is allright because it would reflect mostly green light and plants dont need that part of the spectrum anyway.

another thought is that, a forest basically constitutes a giant green shade cloth and i doubt nature would have made a mistake with this concept. in other words, the plants at the bottom might recieve only very low light levels, but i doubt that the red and blue aspects of the spectrum would have been reduced proportionally to a higher degree than the overall spectrum.

so red and blue shade cloth would have to be the worst.

green shade clothe *reflects* green light....this means it absorbs teh red/blue etc and only bounces off the green, the same as plants. so using a green shade cloth is like taking a light, removing the red and blue from it and jsut shining the green down to the plants....so it is bad.

the color the -whatever- appears as is the colour it does NOT absorb much of...if it absorbed it, we wouldn't see it (all we see is reflected colour/light). red cloth would not reflect red colours, so would allow more red through, or reflect the red back out, same with blue or whatever.

many fruit tree farmers here use white. orchids, ferns, palm trees etc are usually black, but the hole size varies. for example, palm tree shade cloth is coarser (is that the word????? not as fine), and the stuff orchid farms use is much finer (less light gets through).

for things like salvia/psychotria, i would likely go with white, as they dont need THAT much shade...

[kushizm]

True folks, but they do only cover what about 70% of sunlight? How much daylight/sunlight minimum do cactus need a day?

II have had green shade cloth up for a few months, seems to reflect green and normal light, doesnt seem to effect at all?? ANyone care to do some controlled experiments? HAving a hard time seeing how bad it can be..Maybe shade cloth over fluoros for results??

[PD.]

FWIW, i use the shitty ol green stuff. Tricho seedlings go spastic under it but then again i have no comparison as i havent used any other colour. I only use second hand stuff anyways generally so im not about to go spend a crapload on new white cloth to cover the greenhouse just to see if its any better when im gettin excellent results as is.

[kadakuda]

cacti breeders here seem to use black for their cactus almost exclusively. but its only needed for some cacti (like arios)....personally i use nothing.

[planthelper]

green shade clothe *reflects* green light....this means it absorbs teh red/blue etc and only bounces off the green, the same as plants. so using a green shade cloth is like taking a light, removing the red and blue from it and jsut shining the green down to the plants....so it is bad.

the color the -whatever- appears as is the colour it does NOT absorb much of...if it absorbed it, we wouldn't see it (all we see is reflected colour/light). red cloth would not reflect red colours, so would allow more red through, or reflect the red back out, same with blue or whatever.

thx for explaining that, so red blue polka dot shade cloth it is than, lol!!

[kadakuda]

LMAO! that might be interesting!.....but i hate to know what the fly by pigs would think when they see it

[John_Barleycorn]

Correct me if I'm wrong here, but I have trouble seeing how shadecloth acts as either a high or low pass filter at all. I would have thought it simply passes white light through the gaps, and the more gaps the more light. If the size of those holes was comparable to light wavelengths then some interesting refractive effects might occur, but the holes wouldn't be visible in that case. I assume that dark cloth absorbs a bit more heat, but it would also dissipate fairly rapidly. In other words, dark material absorbs rather than reflects infra-red, but I can't see how it would actually pass it. Another point is that shadecloth seems to be rated according to its UV blocking (rather than white light blocking) ability, regardless of its colour. If it literally acted as a filter, then you would presumably want the cloth to be reflecting high-frequency blues.

I tend to think filtering becomes more of an issue in glass rather than shade houses. In fact, I posed the question some years ago about the merits of glass vs fibreglass vs polycarbonate, etc, some years ago, and I don't recall that we reached much of a consensus except to conclude that no plants need UV for growth. Whether plants are actually damaged by UV is another matter. Stuff like poppies doesn't seem to like heat plain and simple, which presumably would be an argument for blocking IR.

[kadakuda]

its not a filter thing its a reflection thing. like you say, black absorbs white reflects. the hole size is a big deal, many sizes available in all colours. but white will *reflect* more of the light down/up/this way/that way while black will just soak a bunch of it up=darker.

[Torsten]

if shadecloth only passes white light then a white piece of paper held under shadecloth would be white. But it isn't.

you are right that the main action is to let through a certain amount of white light though the holes, but obviously the edges of the holes also have a reflective or filtering effect which adds a certain amount of coloured light.

[kadakuda]

i think what we are getting at is it reflects white light. far better than black materials reflecting very little at all.

the same size mesh in black and white will show much different levels of light underneath, mostly i presume due to reflection and less to do with shading/filtering (same thing?)..maybe i am off.

either way, white sure is brighter than black, there is no question

another good use here for white shade cloth is allowing much light through but also keeping the inner area really hot. this is sued for many fruit, especially papaya to help sweeten the fruit. pretty tasty them things are when fully ripe in these houses.

Edited December 23, 2008 by kadakuda

[Garbage]

No mention of this stuff?

http://www.wyevale.co.uk/Cool-glass-greenh...default,pd.html

I leave the bubble insulation on for shading.

Edited December 23, 2008 by Garbage

[kadakuda]

interesting. how is it in rain?

[Garbage]

It resists the rain fairly well.

[Torsten]

No mention of this stuff?

http://www.wyevale.co.uk/Cool-glass-greenh...default,pd.html

I leave the bubble insulation on for shading.

I am confused... what does bubble insulation have to do with the whitewash link you posted?