Definition for light, moderate and deep shade

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H

Hyun007

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Can someone explain this for me?
I read that light shade mean 25% canopy closure but with 5-10hours direct sunlight during summer.
Partial shade(i assumede moderate shade?) 50% closure and less than 5 hours direct sunlight.
Full shade is complete canopy closure with less than an hour direct sunlight.
Deep shade means direct sunlight is block out completely.

Can someone help me with this?
Many thanks in advance.
 
It is important to note that direct light for most orchids means early morning and/or very late afternoon. Also, it depends on time of year as to how direct the sun can be. Be careful of generalizations, and the description you found on the internet is very generalized.
 
It is important to note that direct light for most orchids means early morning and/or very late afternoon. Also, it depends on time of year as to how direct the sun can be. Be careful of generalizations, and the description you found on the internet is very generalized.

Yes, and that is why i double check here. Kind of scary to leave a paphiopedilum for 10hours under the blazing sun.

Slipperfan, can you let me know the morning hours time period for sun and late afternoon please. I am living in the tropic by the way.

At the moment, my light shade are getting direct morning sun till 10:30am and they might get an hour of direct(a little orange) light from 2-4pm.
 
Yes, and that is why i double check here. Kind of scary to leave a paphiopedilum for 10hours under the blazing sun.

Slipperfan, can you let me know the morning hours time period for sun and late afternoon please. I am living in the tropic by the way.

At the moment, my light shade are getting direct morning sun till 10:30am and they might get an hour of direct(a little orange) light from 2-4pm.

I live in the tropics too. Here the sun at 8:00 am can be to intense for any extended amount of time. It depends also on air temperature and humidity.
When you read a plant needs light shade you should assume that means always and never with direct sun that comes from overhead. Just to be on the safe side best to always keep some shade filtering the direct sun. Between 10:00am and 4:00 pm in the tropics the sun is to strong for shade loving plants.
 
They used to say that in general, no shadow should be cast over the plants if you hold your hand about 15 inches (about 35cm) above them.
 
The initial question is a very good one and I'd be glad to know a definition easy to verify and copy.
Independently of the influence of the other parameters that may change the effects of a given amount of luminosity, and without taking into consideration what oneself considers 'shade' - which, I assume is a highly psychological decision, too - it would be fine to have concrete and easily measurable numbers, like we have for tº, daylight length, humidity or even for ultraviolet index', etc.
For the usual recommendations like 'use a 50% shade cloth' may be practical but don't really help to define a value.

So, in the end, it comes to try-and-error, patience and lifespan of a plant to 'get a feeling' for the right amount of sun and shade at your place.

A plant growing in high latitude coming out of winter will be more susceptible when exposed to sun than a plant living in the tropics all the year, and as trivial as this may sound, this is true and gives a hint:
'shade' and 'air movement' are the two parameters in plant care that usually receive less attention but are crucial in modulating the other parameters, like tº, humidity, watering and feeding.
An easy way to measure would be great.
 
There are measurements for light/shade that can be measured with an instrument.

Foot candles and Lux are to light what Degrees is to temperature.
Full sun is 10000 foot candles
50% shade is 5000 foot candles.
25% shade is 7500 footcandles.
ect.

Lux is just a different set of number values but functions the same.
 
Horticulture shade.

In the old days when lath houses were used to create shade for growing shade loving plants there was a formula used to create the correct shade needed.
If you wanted your area to have 50% shade you built the house with wood lath (strips) that were 1.5 inch wide and space them 1.5 inch apart. Doing that means that one half of the sun is blocked by solid wood.
If you needed 90% shade you made the open space between laths be 10% of the area, so 90% of the roof is covered in wood.

The key to the strip lighting working is correct orientation of the spaces. The laths need to run in a north/south direction so that as the sun moves the shadow on the plants also moves. The sunlight coming through the lath is full strong sun and will burn the leaves of shade loving plants if it remains too long.
The sun moves at a speed so that the shadows from the lath move and change constantly so that in reality an area of a leaf gets full sun for the % space of the lath. But it the exposed leaf area is in constant change as the sun moves so exposure to direct sunlight is only for a few minutes at a time. As I recall 50% lath shade would have direct sun on a leaf for only 15 minutes, the time it takes the shadow to move 1.5 inches.

Because of the moving shadow of horticulture shade you can not compare 50% shade to being the same as the plant being in shade 50% of the day like 6 hours of no sun and 6 hours of full sun.

Now modern shade cloth makes it easier.
 

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