Quote:
Originally Posted by Orchidtinkerer
comletely agree to try increasing light or even a different grow light but increasing light intensity is not the same as increasing light duration and should not be treated as the same thing.
It would be similar to trying to cook a pizza in half the time at double the temperature but you can't and neither should you try double the intensity for half the time with plants or increase light hours to increase light.
The light hours tell the plant what time of year it is, when to flower, when to rest and so on.
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1. The vast majority of orchids are tropical and can be grown under lights between 10-14 hours per day. You don't have to change the photoperiod that much because tropical orchids do not experience much change. Plenty of growers grow at 14 hours a day without changing their light timer ever. Some species might need photo-period changes to flower but only one comes to my mind which is cattleya walkeriana and even that isn't settled.
2. Your pizza example is not good. Wood fired pizza is literally cooking the pizza at 500F for a quicker cook time.
3. If the orchids are not getting enough light at this 12 hour photoperiod moving the lights closer is the easiest fix here. Intensity CAN be a substitute for lack of day-length in reasonable contexts.
Here is a DLI chart. If we use reasonable constraints, 10-14 hour photoperiod, 250-400 PPFD you can clearly see that there is multiple ways to achieve the desired amount of photosynthesis needed for optimal flowering and growth. For cattleyas a DLI of 15ish is good. Even if OP cant directly measure his lights, moving them closer for the same time will assuredly result in more photosynthesis.