Seedling light intensity... :-)

I started seedlings day one at 70cm from a 4 bulb t5 2 foot unit which did very well. This seems to be the 100-200ppfd/umol range (which is quite far).

At closer distances seedlings showed hypocotyl and leaf anthocyanin.

Still confused here but results are suggesting the data for seedling light intensity is right.

I said id respond for this test but have no quantum.meter to give more accuracy.

It would seem mj seedlings cannot be placed in anything but weak light but that means most will have to place lights futher away than what is advised.

Ive always had ok starts at 30cm but perfection seems futher away than this.

Looking for discussion or more data to try and determine this, a 250whps needs a shot load of distance to make 100-200umol so im still scratchimg head trying to fathom light distamce data here from umol data which seem at odds with each other.

I don't have any data, just anecdotal evidence; I use a 1 bulb 2 foot t5 ho 6400k, and I usually get to between 2 and 5 cm from my seedlings without any problems. However I also keep my grows at a lower temperature in winter than most, between 20 to 22 C.

i use a 4 bulb t5 in early veg as well. I noticed young plants can take the light a bit easier if they are domed with high humidity. less than 70cm is doable for me only with the dome, lot of leaf curl without it.

CanadianJim said:

I don't have any data, just anecdotal evidence; I use a 1 bulb 2 foot t5 ho 6400k, and I usually get to between 2 and 5 cm from my seedlings without any problems. However I also keep my grows at a lower temperature in winter than most, between 20 to 22 C.

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Without reflector or with?

Without halves the light at a guess

madvillian420 said:

i use a 4 bulb t5 in early veg as well. I noticed young plants can take the light a bit easier if they are domed with high humidity. less than 70cm is doable for me only with the dome, lot of leaf curl without it.

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Domes are bad but thats another thread.

I can do seedlings at most distances and achieve more growth the closer i get but to hit absolute perfection means futher than what every guide says.

It is a long term study i wish to end and have put in a lot of effort to understand stem purpling and leaf morphology at various light distances.

After a couple weeks seedlings (more termed a plant by this stage) can get a lot closer.

I use a 4 ft 4 bulb T5 with HO 54 watt 6500k bulbs. I keep the seedlings a few inches under the light.

I don't have any issues with seedlings being too close to the light.

Shoot for a greater internode length and much bigger leaves - i get what your saying and i can replicate that easily just i prefer a much bigger set of first leaves. This looks too small and compact.

I have bigger seedlings at a lesser stage than yours but hope you see im in no way criticising just looking for more.

To me this looks too close to the light and no stems on leaves stretching out to absorb light and much more compact.

xtsho said:

I use a 4 ft 4 bulb T5 with HO 54 watt 6500k bulbs. I keep the seedlings a few inches under the light.

I don't have any issues with seedlings being too close to the light.

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I have to troll up pics as formats not good with my low fi tech phone - These grown at much greater distance than yours to show the difference hopefully.

I am starting even futher though and talking first week not at the stage yours and mine are at in the pics.

https://www.rollitup.org/t/one-plant-over-two-months-in-pictures.959734/

Hope this makes sense

xtsho said:

I use a 4 ft 4 bulb T5 with HO 54 watt 6500k bulbs. I keep the seedlings a few inches under the light.

I don't have any issues with seedlings being too close to the light.

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Kingrow1 said:

Domes are bad but thats another thread.

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Just can't help your asshole self.

It's one of these. It has a reflector, just not a big one. I have another for larger plants, 2 bulb 4 foot t5 ho 6400k. I can let the plants grow up between the bulbs with that one, but that leads to other problems.

I'm usually fighting to keep internodes down to a minimum with the indoor plants. I haven't had many issues with leaf sizes, except for when they grow larger than the footprint of the light.

I have a closed space for seedlings/starts. All my rooms , in various stages of growth, have doors that open to a common room, so everything is sealed and ventilated but this rooms 8- 2ft bulb cfl was killing me with heat issues, so I bought a mars spl150 so far I can keep the light close enough to have an affect. so all thumbs here

See how much growth them pics show for a couple flouros.... WoW

This always confused me and makes me think we underestimate light. Obviously just a pic but ive seen it with other grows peeps have done.

Smart peice of kit though for lowering and raising they sell well

CanadianJim said:

It's one of these. It has a reflector, just not a big one. I have another for larger plants, 2 bulb 4 foot t5 ho 6400k. I can let the plants grow up between the bulbs with that one, but that leads to other problems.
View attachment 4446233

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Kingrow1 said:

Shoot for a greater internode length and much bigger leaves - i get what your saying and i can replicate that easily just i prefer a much bigger set of first leaves. This looks too small and compact.

I have bigger seedlings at a lesser stage than yours but hope you see im in no way criticising just looking for more.

To me this looks too close to the light and no stems on leaves stretching out to absorb light and much more compact.

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I like a short internodal length. I try and grow short bushy plants because I'm growing indoors. I'll top at about the sixth node and then start supercropping. These were topped at the sixth node. They're exactly the way I want them. They end up exploding once I put them into three gallon pots of coco.

Kingrow1 said:

See how much growth them pics show for a couple flouros.... WoW

This always confused me and makes me think we underestimate light. Obviously just a pic but ive seen it with other grows peeps have done.

Smart peice of kit though for lowering and raising they sell well

Click to expand...

they look healthy and compact, I just couldn't get my lights close enough for cfls to make a difference, if close proximity is your grow option cfls wont disappoint

Your plants look great but i prefer size over compactness. More light means leaves neednt be so big but im shooting for perfection so i am questioning light levels.

You are right as dutch growers did the same with compactness just im shooting for natures version of perfection and less light grows bigger plants.

Its always been hard for us to get perfection at day 3-4-5-6 and we see growers start then not post pics till past this initial sensitive time.

You must forgive my quest to find that certain level as it is a bit anal but after years practiscing it pisses me off now lol.

Great plants dude

xtsho said:

I like a short internodal length. I try and grow short bushy plants because I'm growing indoors. I'll top at about the sixth node and then start supercropping. These were topped at the sixth node. They're exactly the way I want them. They end up exploding once I put them into three gallon pots of coco.

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Valid point, cfls are weak so much less stress, ive had love affairs with 125w cfls upto the 250w cfls and by darn they were easy to grow pretty great plants with but sucked at penetration. T5's appear stronger lights or tubes should i say and with reflector more so.

Id look a noob using them but i do want to go back as some of my best plants were with them

rustyshaclkferd said:

they look healthy and compact, I just couldn't get my lights close enough for cfls to make a difference, if close proximity is your grow option cfls wont disappoint

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I think the difference in penetration has more to do with the length of the bulb allowing more light in from the sides. Which would work better with slightly longer internodes.

Been interesting thread and to see xtshos plants.

I will keep at it but if i.leave some more data ive read on how much light it takes to make a seedling stretch and that is well below 100umols more like 20-50 as far as i can read.

Growing is an ongoing quest for me i guess but feel.one day i will know enough to grow any speciecs not just mj.

Thanks guys ill repost soonish see where im at