Lighting question from germination to seedling

good day and happy new year. i’m starting my second grow (first not so successful). my first question is simple i guess, but i can’t seem to find a definitive answer so i’ve come to the experts. seeds germinated. now in soil. how high should i place the lights above the seeds during the first few days? looks like some of the articles on this site say 2-4 inches, and i’m assuming that’s until they break the surface of the soil. then 20-24 inches right? Mars Hydro 1000 LED, i have 2, in a 3 x 3 grow tent. four jack herer seeds. i’m determined to get this right. help please!!

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When in seedling stage they need very little light. You could use a desk lamp if you wanted to. That being said I start my seedlings off at the same thing my tent is usually at and that about 250-350 umols as thats whats need for the veg stage. If you can’t figure your umols or DLI get a lux meter or download the photone app

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2-4 inches is for those using T5 style bulbs or household LEDS to pop seeds.

U dont want to run a 200+w light within inched of seedlings. I use the same light start to finish and typically start at 2-3 ft away.

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Like Purp said.

What I do is run lights (QB135 B-spec) at around 100 watts (same as your light) at a height that a: keeps plant temperatures around 78 to 80F and growth is not too ‘leggy’. If you use those as your basis for light height you should be fine. I also run 24/0 to maintain conditions until plant is established. Once I transplant it goes under an 18/6 light schedule.

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Fun fact if you have an android you can use this code in your dialer and it has a lux meter option. Once you enter this code #0# (star, pound, 0,star, pound) you can select sensor and it will show you lux somewhere in there. To back out just spam the back or home button


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I recommend measuring light with a meter vs a tape measure

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thanks to all. i’ll get a light meter.

Here is the meter I use. Love this thing

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