I don't think that anyone has provided that type of information. However, I don't think that you can be that specific or would want to be. There is a range of acceptable light levels for many plants, and there are a range of things that effect how well a plant does within a given level of light. For instance, in my zone the active growing season is only about 4-5 months long, and the light levels the rest of the year only matters for broad-leafed evergreens IME. Moisture levels will effect how successful a plant is within a given light level. So for example, I've seen several folks comment that this far north they find that full sun (or even all day sun) is fine for the hydrangeas that generally do better in afternoon shade (H. macrophylla and H. arborescens) though in my well-drained, mostly unirrigated garden they wouldn't do well in afternoon sun.

NHBabs, thanks for your input. I'm still trying to figure out how to quantify "shade" vs "light shade" etc. I have various areas where my DLI is as low as 6. I'm experimenting with shade and full shade plants to see what works in that environment but it would sure be easier if there were some studies that have looked into this.

There's adequate information regarding what plants will grow under what DLI levels; see https://www.extension.purdue.edu/extmedia/ho/ho-238-w.pdf

But retail plants are sold, and internet information, all point to generalities such as shade, light shade etc. without reference to DLI. The question remains, how to connect the two????

Those guidelines for retail plants are just that, guidelines that are geared for average growing situations. If you live in a climate that is more extreme in any area other than light you have to adjust accordingly. So for instance, I grow Hydrangea paniculata in full sun (12+ hours in midsummer) with no irrigation while someone in TX who posts on the Hydrangea forum needs to provide part shade and irrigation for them if they are to do well. My nights are cooler, though my days may not be, so the overall average temperature of the plant is lower. Where are you? Generally, if you are farther north or in a cooler area or at a lower altitude, you can get away with more sun on the range the plant tag suggests. At a high altitude the atmosphere is less filtered so light shade might provide more moles than at sea level. So really, you will just have to experiment with what works for you, based on a combination of light levels, soil texture, moisture regimes, and temperature.

Hi John,

It would help a lot if we knew what purpose the DLI knowledge is serving, bc we can only really answer with other units and descriptions.

-For one, try matching the plant you want to grow with one on that Purdue list that has the same requirements for light and temperature at least. If they have similar needs across the board, with acidity and other needs too preferably, it's safe to move forward with the list-plant DLI as your DLI for the plant you want to grow, affording yourself the ability to adjust slightlt from there. Better to add shade you can remove than to plant in shade with no way to add more sun.

-I would add that Direct sun means direct, if a plant needs full sun even a full day of bright indirect light won't do. Def make sure your *temperatures* and light are both correct, this will help you narrow down acceptable spots. *Again, temp is a factor.

-Also, the difference between afternoon and morning is important. Afternoon sun is like 1.5 to 2x the 'value', at least, in terms of heat and light "saturation* coinciding. It's rough, but a fair number for gardening purposes, if that helps. So 3-4 hrs afternoon or 6 hrs morning is okay for a partial shade plant....

>>In the desert that number is way higher, I would say 3-4x (at least) as much in the afternoon (from 8am to 6pm in the summer) but most zones it's a good estimate to say afternoon sun is <= 2x morning sun. In super foggy and cloudy places, the number is lower. Sensitive plants should get morning sun (like loose lettuce)<<

.... These numbers are not DLI related, but rough gardening metrics.

-In terms of finding DLI, do your own experiment! :) Put the plant where gardening advice, without the math, says to do so, make sure it gets everything it needs by garden wisdom, then measure the light throughout the day and see what you get. If it's getting the right number of direct sun hours, temp, soil needs, the plant will grow well and your readings will be worth tracking for future use.

-Also, look into books on growing cannabis, there's a lot more fine tuned science in that kind of stuff, especially about lumens.

...

I also like math and biology, but gardening, especially sun measuring, is more gestalt than the fine quantification you're trying to do. PH, EC/PPM, these are quantified, But water is done based on inches above soil and feeling moisture with the hand, light is measured in hours of direct* sun. These techniques and knowledge have developed over millennia, well before moles were defined. It's all pretty flexible, and intuitive, for most plants. I'm sure you've heard this. One season of gardening allowing yourself to fail and try again will help a lot. The first is the hardest! Try finding a friend or mentor to help with their intution and remember your senses and their advice along the way.

As a metric, Minimum 6-8+ hours for full sun. Part sun/part shade is 4-6hrs, with most preferring long morning to a short afternoon. Shade is 4 or less (some say 3). However, some plants need No direct sun, make sure they get lots of indirect light though (such as many carnivorous), again read up on them to see how much light they need. Most plants are adaptable to a (limited) range of conditions, so the specific DLI isn't necessary. ---