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lighting Light distance from seedlings?

What is the proper light distance from seedlings? I know it matters with what type of light, but a low watt full spectrum grow tube from Walmart for example. Researching on the internet of course you can get 2 totally different answers, one I looked at said 1-3 inches, the other said 18-24 (assuming that is probably a fairly strong light) I suddenly have to go out of town for the weekend so they are fresh under the light as of this morning, they been growing in the seed trays that have little cheap full spectrum ledโ€™s in them, but now under the tube light. Hereโ€™s the
Light in question, i have some Mattapenos that popped first and are trying to get leggy before the others. Just donโ€™t want to come home to a disaster. Thank you in advance for any help

 
It does matter what type of lighting you are using. I have several "shop" lights that I have to keep much closer to plants and some LED's I purchased from Amazon that can be much higher. To be honest, I've always adjusted by what the plant is telling you. You want a few inches away from Shop lights and more with LED - but the plant will tell you by stem. If it starts showing purplish - lights are too close... adjust up some. I know not the direct answer you were looking for but this question has always been something I've looked for an answer for myself :) Just read your seedlings/plant as they grow.
 
I bought a full spectrum led grow light recently because my seedlings were getting leggy, but because it is a non dimmable cheapo, I was worried about hitting them with too much light. Watched a video yesterday where the guy said you can't actually have too much light as long as the lamp isn't close enough to burn your plants. Any thoughts on this, folks? He has a large grow room, with lamps giving out something in the order of 30000 lumens.
 
Usually the grow lights come with instructions regarding distance to plants and coverage area. I use that as my starting point.

Iโ€™m interested in trying one of those light intensity PAR meters in an attempt to be more precise.
 
I did not realise the plants would get so big so fast. Still at 40% & as high as I could raise the lights, I never did anything as they were growing so well. How close is too close, & what should the power be set at? None of this in the Mfgs instruction's.

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And how were you're plants when you came back, @JH4FSU? I cannot advice buying lighmeter or, if that's possible, downloading free app on the phone which will measure the lumens' count more. All of my worries went away when I did it.

@Marturo They look healthy. I saw peppers touching the light and growing out the systems with light build in it, I think that if it doesn't give heat, it's alright and plant knows how to grow towards or around it. Like when it's small and its leaves start to bump up to make a shadow for itself. I think 40% is enought because it works and if they wouldn't like it, you wouldn't need to ask yourself those questions, you'd see that they don't like it. We live faster than them, we have more time to react. :halo: ๐Ÿ˜‚
 
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@Marturo They look healthy. I saw peppers touching the light and growing out the systems with light build in it, I think that if it doesn't give heat, it's alright and plant knows how to grow towards or around it. Like when it's small and its leaves start to bump up to make a shadow for itself. I think 40% is enought because it works and if they wouldn't like it, you wouldn't need to ask yourself those questions, you'd see that they don't like it. We live faster than them, we have more time to react. :halo: ๐Ÿ˜‚
Well so far 40% has done the job. I have not seen any signs of the light being too close and burning the plants.
I'm still stunned by the difference in LEDs & fluorescent bulbs.
 
I did not realise the plants would get so big so fast. Still at 40% & as high as I could raise the lights, I never did anything as they were growing so well. How close is too close, & what should the power be set at? None of this in the Mfgs instruction's.

1709996501024.png
How old would you say those plants are?
 
Does this mean that there are some types of chillis which you shouldn't you shouldn't put with certain others under the same light, or are the differences in tolerance not so dramatic?
See pic.

Both plants hooked on same day.

Plant on left (Joe's Long Cayenne) is C. Annuum, plant on right (Scotch Brains) is a C. Chinense cross.

Both have four sets of true leaves, but note the interstitial spacing. The Annuum typically are more "stringy" while most Chinese are more compact.
IMG_0382.JPG


Depending on your lights, you may need to place them closer to the shorter plants, if you notice they are stretching. I never really notice that with my setup.
 
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