Light distance

do what i did download the photone app

its different cuz all lights are different. look at the manual for the make and model of yours and go from there. 300w in one brand is not always the same as 300w in anther brand. espicailly if they are useing diffrent techs like LED vs HID vs CFL The best ratio to operate off of DLI and DLI changes on the PPFD, PPFD is affected on how close the light is. Wiki has a nice rundown on DLI, but if u want to keep it stupid simple. read your manual.

There are variables invovled, so whatever you start at, you must observe and adjust based on plant growth. too lanky, needs more too tight, needs less When you find that happy zone, you can use something as simple as a klux meter app on your phone to measure and repeat. Different seasons might result in different temp/rh / even atomsophereic co2, which all influence how much light you can give per day... it varies. A QB i'd start at at least 18" (full power, not some seedling context) With something wiht better-distrubtion of diodes, like a bar-frame light, 14-16" might be all you need. What plant is in front of you may have some small impact, too, but less than you may think. There's no way anyone can give per-strain advice as each seed is going to have some diversity. Again, if it's all based upon plant growth, it's good to go. Suggestions are just a good starting point.

Hello You can find some free Apps in the App store of your choice to check for ppfd and dli as others already Pointed out. I usully try to keep the light at 30-40cm distance and Dimm the Lamp to my needs. Check via free phone app for the stats to adjust. Start with 150-300 ppfd :)

General terms....... 24 inches for seedlings 18 inches for veg 12 inches for flowering.

Hard to tell take a look at the manufacturers recommendations. Ideally they have a ppfd map for the lamp at certain distances. This way u can dial in the daily light integral to the right amount. Ppfd of 150-200 umol/m2/s should be fine for seedlings with 18/6 light cycle. That would be a DLI of 10-13 mol per day.

it a strong light for seedlings but if you raise it high and turn the settings down because they only need a small amount of light st the min..