Ppfd for each stage experience with phone apps for ppfd/dli

Phone apps can be used. However you will need a lux meter to calibrate it. Look up Migro and type in PAR meter hack on YouTube. At the cost of a £30 Lux meter you can really dial in your DLI. Then if you like download ppfd meter app on phone calibrate your lux and phone. Beats paying £500 for a par meter. Good luck !

Thanks guys for your time effort and great advice.

phone apps are not precise.. they are accurate (which just means they'll be consistent under any 1 light). a different spectral flux density will cause a different result with a simple calculation tht the phone app is using.. the phone is not a quantum meter. it can measure lux, poorly, though. lux is then converted with a not-1-sized-fits-all factor, which is why you maay see variance in lux readings based on the equipment you are measuring. it will be consistent under any 1 light. knowing relative intensity can be just as good as a real quantum meter. so no phone app is "good" at it. the camera lense is a poor receptor given it's wide angle of view. buy a cheap 8-10 dollar lux meter... or use the phone apps... relative intensity is wht you can map out and adjust with it. ppf is fancy and nice, but so many variables impact how much you can apply in your garden vs someone else's. so, the precision may make you feel warm inside but the same trial and error involving observing the plant is necessary to dial it in properly. internode distance -- too long, needs more light. too short, needs less light. then of course the more obvious physical damage that results from too much light is even easier to react to. so, start a little weak with seedlings, watch and react to stretch. make anote of lux reading or bullshit phone par/ppfd reading, lol. start there next time. repeat throughout life cycle.. take notes.. follow plant next time. seasonal differences are possible.. varying temps, rh, even co2 are possible. i'd wager there's more co2 in your home in colder months with all the windows closed, multiple people inside breathing and the furnace on. but, the vpd may be so off that the plant doesn't make use of it... so many possibilities that every garden can be quite a bit different as far as the max light or max feed you can provide at any stage. quantum meters are 500 USD... if it isn't 500usd it's probably bullshit... if it's 500usd and it's an app on a phone, it is bullshit :P whether you use photone or a lux meter on phone.. doesn't matter.. familiarity will be gained over time.

Doggo apps. Lux light meter pro. Android phone with good camera ( photo element sensitive depends from that). For branded Led light Germination and first week : 5000 lux and 30 cm 1-2 week of veg : 10k and 40cm 3 week veg : 15k 40 cm 4-5 weeks of veg 20k 40cm Flower 1 week . 30k 40 cm Flower week 2. 40k and 40 cm Week 3 flower 50 k 40 cm Week 4 flower 60 k 40 cm Week 5 - max light output, 40 cm Week 6 : max output 35 cm Week 7 max output, 30 cm Week 8 and till end : max light output and 30 cm distance to top level of canopy Thats my sipmle math, but its for healthy max 40 cm deep canopy to penerate through. Off course healthy pkants, of course good humidity, aka following VPD by plant stage and many more factors for everything to work well. That measure is taken at top level of canopy, ussually i had really even it, thats why i said 40 cm deep.