Quote:
Originally Posted by camille1585
With the conversion factor from natural light to PPFD, 50K LUX should be around 1000 PPFD, so that's correct. As to the 200-300 μmol/m²/s , that seems about right to me. I work at an indoor farm company and we can grow tomatoes commercially under LEDs with 250μmol/m²/s, and tomatoes have rather high light requirements.
Most resources seem to base their recommended light levels on the max light a species/genus will receive over the course of the day. If you consider the natural progression of light intensity over the course of a day, the averge value is far lower than that. That's also why it's far better to work with DLI, or Daily Light Integral, which is the cumulative amount of light a plant needs over the course of 24 hours. This is dependent not only on the PPFD, but also photoperiod. If you take my tomato example, this crop needs a DLI of 14-18 mol/m²/d. 16 hours of 250μmol achieves that. Phals have a DLI of about 4, Cattleyas 10-15, Dendrobiums 8-10, at least from what I read last year when doing some research for work.
Don't covert the PFFD units to square feet, it's metric unit and meant to be in m². ;-)
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Hi,
I just experiment a bit with light, light intensity etc.
I had the Information of arround 50k Lux too.
The energy the plants can collect over the day is important, but... you can't compare CAM-plants to C3 or C4 plants.
Tomatoes, canabis and co. just need a short night cycle becouse they collect CO2 at day.
Cattleya are CAM-cycle-plants, collecting CO2 just at night and use this to modify it to sugar at day.
So you need a balanced Day-Night cycle to give the Orchids the time to collect the CO2 at night.
Next thing, near the equator, we don't see such a big difference in light intensity like where we live (I am from germany by the way).
So in the morning the sun rises verry quick and on the evening it becomes dark verry fast.
So the orchids don't have such fading lights like we know.
It the moment I have a small tomatoe-tent with a shelf of 90x45cm footprint and use 3x 70W HQI CMD-tc 942 lamps + some T5 LED strips to illuminate the sides a bit.
12h Day, 12h night.
Temperature 28 °C at day, 18 °C at night. Humidity 70% at day, 85% at night.
PPFD depends on position and hight between 300 umol/s/m² and 1100 umol/s/m²
It is a test with some cattleyas I saved from a market (some of theme were more dead than alive)
Some of them are already well established and grow on 2 to 3 ends neew bulbs.
If this will go out well, I will start recolecting C. rex (I lost all of my plants on a buisnesstrip and my neigbour gave too much water)
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