Light & Temp

[shadytrake]

Hi Everyone,

Rick got me to thinking last night about my light and temps so I thought I should take some readings and get your feedback.

My shadehouse is situated in the East part of my back yard.

As you can see from the photos, I can't do much about the neighbor's Crepe Myrtles and Pine Tree blocking some of the Easterly light during the summer but during the winter, I get pretty good light.

To the North, I have direct sun. To the West, I have pretty direct afternoon sun because that stump of a River Birch has been trimmed back to get Cattleya light and the hundred foot American Elm (commonly called a piss elm) was felled in a storm six years ago. To the South, I have a Magnolia Soulangiana as an understory and a fifty foot American Elm that sits right on the property line. No getting rid of that monstrosity without some serious $$.

Today's readings were taken at 11:00 am Central on a mostly cloudy day with the outside temperature of 76 F. (side note: yay, I can finally fertilize).

You can see by the light meter that I am getting good light in the Paph/Phrag area on the Eastern side in the morning and the Western side has lower readings.

Those readings will go up steadily as the sun moves overhead. I'll take readings again at 2, 4, and 6 pm.

You can also see that the Bulb and Phal areas have reduced light (they are also on the Eastern side).

This thermometer is right over the Paph/Phrag area.

Based on these limited readings, do you think this morning light is too much for the Paphs? Do you think I should move them down to the Bulb/Phal area? It is also cooler there by about 5 degrees because it is lower to the concrete.

Thoughts?

 

[mrhappyrotter]

I'll be interested in the responses as well.

I have one of the cheap light meters and grow under T-8s with minimal supplemental light coming from a small, shaded window. Anyway, it's my understanding that the light meters don't work particularly well for measuring FC with artificial lighting, but when I switch the meter to FC x10 and put the probe on top of the plant leaves, I get readings that go from about 22 up to around 65. That implies 220 FC to 650 FC, which sounds low.

That being said, most of my plants have light green leaves and red pigmentation (suggesting that they're on the upper end of their light preferences). They grow and bloom well with these light levels. In fact, I managed to grow peppers under these light levels, and regularly bloom certain cacti. So again, it leads me to believe that the light meter isn't all that great at accurate measurements for fluorescent lighting, or else I've horribly misunderstood what the FC x10 readings correspond to.

 

[shadytrake]

mrhappy,

I too, thought I was misreading the meter. It wasn't particularly cheap to purchase.

I think my issue, other than the high K, are summer temps on some of these chids. Without completely saturating, sometimes you just can't reduce in a shade house. That's one of the reasons I am switching back to some clay pots and baskets with moss.

Just took 2nd readings.

Paph/Phrag area: 40 x10 setting
Top of SH facing west: 50 x10 setting
Outside facing west: 130 x10 setting

It is mostly cloudy and we are getting rain showers. Temp 79 F.

 

[Rick]

light changes so much over the coarse of the day and even by incident angle it's real hard to say what's correct or not. The plants tend to be the big averaging measuring devices so I'd rather "read the plant" than a meter these days. Most of your plants have pretty nice color, so maybe judge your light by the appearance of the oldest plants in the various parts of the structure.

Temp is more straightforward, but since it got so cool out there, the light/temp interplay is not representative of your more extreme conditions. I see that the whole structure is surrounded by black shadecloth. I think that might exacerbate your heat problems on sunny days.

I used to use black cloth (but now use Alumanet). When I was using black, it did cut back light, but built up a lot of heat underneath. One summer it got so hot under the cloth that it softened up the PVC pipe frame and bent it. The fogger (which was hooked to both temp and humidity) would run almost continuously. After going to aluminet, the cooling systems don't need to work nearly as hard and cycle on/off as targets are met.

There are high and low light paphs and phrags. I have different things on the east, center, and west side of my GH to take advantage of what I perceive are different light requirements for the different paph species.

 

[shadytrake]

Hi Rick,

The structure is built with pressure treated lumber with standard screen door cloth so that can't be changed without major work and expense. However, the draped shade cloth is not permanent. I'll see if replacing with Alumanet is feasible in the budget.

Thanks for the tip. It always helps when you can get the big picture.

 

[goldenrose]

Aluminet is the way to!