What are the light distances from canopy for each stage
This depends on your light. What kind are you using…
But as a general rule, 24-36 inches is good, lowering if you see the plant stretching, raising if you see heat/light related leaf damage. I keep mine about the same distance above the canopy for the whole grow…
@Kurt It is getting to the point that phone apps can give you a fairly accurate reading on the PAR reading of lamps, they work especially well with quantum board lights. They are free or inexpensive so you don’t need to guess at how intense the light needs to be. No more need for trial and error.
What you need is guidance on what the readings mean.
If you go by DLI or daily light integral, then seedlings and clones need 10-15 DLI. Veg needs 25 starting out to 45 in 4th week, and in flowering, they need a DLI of between 25 and 35, with peak mid flower.
If you go by PPFD the light requirements are affected by number of hours of light, but for a typical 18/6 schedule, seedlings need 200-300 PPFD, and 400-700 for veg. To reach a DLI with 12/12 hours during flip you need more light. 600-800 PPFD. There have been some recent threads on DLI you could search out for more info.
Hope this helps, no need for trial and error or guessing anymore. Just an app!
Many factors to consider