Excess of light without excess of heat

[DavTom]

Thanks Ray. Basically you are saying that with less heat (i.e., due to frequencies outside the PAR interval) the plant can get a bit more light within the PAR region, but not much more. OK, got it.

Yes, of course, PAR without specifying the time exposure does not mean anything (that's why the assumption was considering as example a 12 hour exposure).

Dav

[Ray]

Originally Posted by DavTom

PAR without specifying the time exposure does not mean anything

Actually, PAR is pretty meaningless...

"PAR" specifies a "color" - a range of wavelengths; nothing else - sort of a broader extension of "red" or "orange" or "yellow", "green", or "blue". It is just saying "all of the above", which constitute Photosynthetically Active Radiation - i.e., what the plant can use. It says absolutely nothing about what energy they are getting.

[DavTom]

Originally Posted by Ray

Actually, PAR is pretty meaningless...

"PAR" specifies a "color" - a range of wavelengths; nothing else - sort of a broader extension of "red" or "orange" or "yellow", "green", or "blue". It is just saying "all of the above", which constitute Photosynthetically Active Radiation - i.e., what the plant can use. It says absolutely nothing about what energy they are getting.

Well, I forgot to mention another assumption I made, otherwise I agree that just knowing the PAR and the time of exposure (i.e., the DLI) is not enough to draw any conclusions on weather a plant is getting enough/good light.

I made the assumption that the good led lights available nowadays in the market (like the Viperspectra I am using) do have an optimal spectrum output. This means that within the PAR freq. boundaries, the spectrum is very similar to the spectrum of the sun (actually, these good light brands do pump a bit more the red frequencies w.r.t. spectrum of the sun, as this is proven to be very beneficial).

Now, if we know upfront that the light we are using has a good spectrum, then by adding the PAR level and the exposure time (i.e. the DLI), we have all what we need to know.

I will keep experimenting with (very) high DLI with some of my orchids (as below) and report here in the forum the results on monthly basis:
- Pahls: DLI of 12
- Bulb and Dendr: DLI of 15
- Cattleya: DLI of 22

And of course I will make sure that the temperature ranges and the humidity will also stay within the optimal values.

Cheers,
Davide

---------- Post added at 11:50 AM ---------- Previous post was at 11:26 AM ----------

Originally Posted by SouthPark

There's something about the temperature too. If the temperature isn't in some particular suitable range, then the photo-synthesis process won't happen ---- aside from having enough water and anything else it needs for that process.

Indeed, thanks for reminding that.

Dav

---------- Post added at 12:06 PM ---------- Previous post was at 11:50 AM ----------

Originally Posted by thefish1337

I think you're pretty spot on with the PAR you're hitting the different species with. Temps look good too. As long as you are running decent humidity I wouldn't worry about your current conditions much.

This guide might be helpful

in my experience I have been shooting for a DLI of 4-6 for low light orchids, 6-10 for medium light orchids and 10-15 for high light orchids. as long as you aren't operating at extremely high temperatures and low humidity dont stress if you're giving them a bit more.

Thanks for the link!

Dav

---------- Post added at 12:28 PM ---------- Previous post was at 12:06 PM ----------

Originally Posted by thefish1337

I think you're pretty spot on with the PAR you're hitting the different species with. Temps look good too. As long as you are running decent humidity I wouldn't worry about your current conditions much.

This guide might be helpful

in my experience I have been shooting for a DLI of 4-6 for low light orchids, 6-10 for medium light orchids and 10-15 for high light orchids. as long as you aren't operating at extremely high temperatures and low humidity dont stress if you're giving them a bit more.

I did the DLI calculation, I am significantly higher than what you are using...See one of my replies below.

Cheers,
Dav