Stretching seedlings. Light distance for LED in seedling stage

DoubleAtotheRON said:

You just have to adjust accordingly. Every strain/pheno is different. Some will stretch no matter the manipulation in light. After cross breeding this plant for decades, there has been a DNA drift.... nothing is as stable as it was 100, or 1000 years ago. Same thing as humans. The human race was once pretty stable outside of disease. Now, we have defects and mutations. I've had the same strain, but different phenos do fine, but the phenos are completely different...I had one pheno from a mother (5 babies) that just died mid flower from the same mother (never finished the mother), but they were all from M5 of that strain. I try to explain it like this. You have 2 parents that have 12 kids... are they all going to be identical?.. no. Some are going to to be short and fat, some skinny and tall, some retarded, some smart (good structure), or just die..... just like humans. This is why pheno hunting is important these days. You want to find that one kid from the parents that is smart, structurally sound, healthy, .....snip....,

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jimihendrix1 said:

At the equator the PPF is 2000umol. So seedlings at the equator are regularly exposed to 2000umol. And at high altitude, its even more.

Ive used 1000w HID since they came out in the 70s for everything from Seedlings - Flowering. I also veg on 24/0, unless Im trying to slow them down.

I found no downside. I did switch from 1000w Metal Halide to Hortilux HPS when they mixed in a bit of Blue in the 90s I believe it was. I do have really really good outside air exchange. And there is no added CO2 at the equator. I believe the main thing to using high umol is air exchange, if not using CO2.


2000 µmol/m 2 /sec
At the equator, the sun’s intensity gives us a Photosynthetic Photon Flux (PPF) of 2000 µmol/m 2 /sec of light, which is roughly equivalent to 10,200 foot candles or 108,000 lux.

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smokey0418 said:

I would also run 18/6 and as mentioned you would adjust your dli if there tired lookin.

In flower I would like to push 9-1000 at the tops.
This would be a gradual transition but once there’s something worthy on there I’m pushing.
This is not plug and play hps.

Good luck with your grow.

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curious2garden said:

View attachment 5284921

View attachment 5284921
These are 3-4 days old. They are 24" away from an HLG 250W Veg Pro dimmed to 10%, no stretch. My PPFD is 263 at their canopy height.

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DoubleAtotheRON said:

You just have to adjust accordingly. Every strain/pheno is different. Some will stretch no matter the manipulation in light. After cross breeding this plant for decades, there has been a DNA drift.... nothing is as stable as it was 100, or 1000 years ago. Same thing as humans. The human race was once pretty stable outside of disease. Now, we have defects and mutations. I've had the same strain, but different phenos do fine, but the phenos are completely different...I had one pheno from a mother (5 babies) that just died mid flower from the same mother (never finished the mother), but they were all from M5 of that strain. I try to explain it like this. You have 2 parents that have 12 kids... are they all going to be identical?.. no. Some are going to to be short and fat, some skinny and tall, some retarded, some smart (good structure), or just die..... just like humans. This is why pheno hunting is important these days. You want to find that one kid from the parents that is smart, structurally sound, healthy, gets a PHD and becomes a brain surgeon, and clone her.

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Moflow said:

Slightly off tangent.
I'm ~ 3800 miles north of the equator and on a rare sunny day I can squeeze over 2300 umols from the Sun.
This was picture taken around miday ~ 21st June a few years ago.

View attachment 5284999

The sun is out right now so I nipped out and took a measurement, it read 2600! That's in April Go figure

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