LED's and stretch in flower?

FedLagNoMoe

420 Member
Is the stretch in flower with LED's comparable to HID? I've heard that plants will stretch a bit less with LED's, strain dependent of course, but I'm just thinking in general terms. My plants are around 30" (not including pot) and I have about that much room for stretch, then they will be getting about 12-16" below light as they will be up against the ceiling. I've got a number of the Mars II 900's, each covering an area of 3x3, about 50 true watts per sq ft., 2 plants per light. I haven't had any problems yet with bleaching, even though some of the taller plants have gotten closer then 12", though never for more then a day or 2. Not really sweating it as I know I can just tie them down a bit, just wondering what other LED users have observed. Thank you and :Namaste:
 
Current plant for me stretched for 1.5 weeks. Started at 12" tall, only grew to just over 16" keeping LED at about 22" and not moving the light at all.

IMG_20150531_081533_886.jpg
 
Thanks Antics. 12-16", that's not much. I've got my lights at 16". I think I'll move one of my lights up to 24" and see if distance from the light has any effect on stretch. What are your genetics, indica, sativa, etc..? I'm going to measure mine every 4 days or so and post it here for the record. Thanks again Antics!
 
That particular plant is Delicious seeds Cotton Candy that I got from Herbies as a freebie in one of my orders.
75% Sativa 25% Indica, Feminized.
! Delicious Cotton Candy Feminised Seeds - Herbies Seeds

I have also LST'ed the shit out of my plant, so some of my stretch ends up as horizontal growth, as seen here, slightly older picture, from May 28, so 5 days old, but still pretty similar to today:
IMG_20150528_075047_258.jpg


But every strain is different. Some will stretch a lot more than others.
 
Day five of flower. 20 plants, 18 strains, 24-35" tall, all from seed. Everything stretched 1-3 inches with lights at 16". Not much at all! I want to minimize stretch somewhat, but damn, that's not much. I went ahead and raised all lights from 16" to 22" above plants. With the exception of one strain which is showing both nitrogen toxicity and phosphorus deficiency, everything looks to be thriving. See ya in 5 days.
 
FedLag: If you want them to stretch a bit more move the light up to about 24 inches or even 30 inches. A Mars 900 at 16 inches will keep the stretch to a minimum. Once they stop growing upward you can move the light back down. Keep in mind the Mars II lights are 5 watt and pretty intense.
 
Zero: Yeah, I went ahead and took your advice, moved them up to 28"on day 6. On day 10 they stretched another 4" or so with the lights at 28". I moved them back up to 28". Day 15 (today) and they have only stretched another inch or so, so I guess the stretch is pretty much over. So, so far only about 15% average stretch. My stretchiest increased by about 50%, 19-29"(Romulan Kush/Sour D), the least stretchiest by 10% 28-31" (Flower Child Granddaddy purp genetics). I wonder if having the lights at 16" the first 5 days set the stage for minimal stretch even though I raised the to 28" on day 6. Wish I woulda had a few lights raised high on day one so I'd have something to compare. Oh well. Going well though, all marble sized and bigger buds, stacking up nicely. Going to do some lollypopping/defol in a week or so, I'll check back then.:allgood:
 
I have seen this reaction to LED lights first hand. Not all types of plants will do it, and I haven’t seen this at all using HID lights.
I discovered this by accident........I had a bud plant that grew to 10 inches and stopped. I thought it was just a runt.
I was seeing a small amount of bleaching from the LED light and moved it up 12 inches and after a couple of days the plant started upward growth again. And continued to grow normally. So their is a learning curve to using LED and finding the sweet spot for optimal growth at different stages. Now once the plants are into full flower you should be able to lower the light if you choose to. Just keeping an eye on any possible bleaching which you probably want to avoid.
 
Thanks for the info and advice, Zero. Yeah, this is my first indoor, never used HID, so nothing to compare to. I started with 18 strains from seed. 2 of them, Critical Skunk and Glazed Cookies didn't seem to like the LED. Simultaneously showing N toxicity, cal/mag and phosphorus deficiencies. Same water and nute regimen as the rest. They'er out in the greenhouse now and are doing better. Here's a pic of my room on day 12.
day_12b.jpg
 
I think you need to attach the small led lights with a wire around the stringer areas of flowers which provide an extra care and works perfectly.

:hmmmm:
 
Hey Fed, have you try to check your ph? It should be around 6~6.5, also more cal and mag is needed. :circle-of-love: Also, don't forget the RH above 50% :thumb:

Hi Sara,
I'm in organic soil and nutes, so PH is not as much of an issue. Like I said, it's only 2 strains out of 18 that are a problem., so I just wont be running those 2 in future gardens. I'm using CalPlus organic and epsom salt, and it's working well on all the other plants. I keep my RH between 40-50% to avoid PM and bud rot. Is there some reason to run higher RH with LED's?
 
How much Cal/Mag? More than what the GH Trio provides?

My Cal/Mag strategy isn't to add more at feedings, but more often in moderate amounts. Outdoors I only used it every 4th or 5th watering/feeding, now I'm using @ 50% every time I feed/water. If you add too much of any supplement/nutrient at one time you can lock out other minerals. Another observation I've made with LED's (and I"ve also read this on the Web) is you don't need as much N.
 
High Fed, thanks for your reply. FYI, usually during veg, if the RH is below 50%, the plants might get bleached. For the cal and mag, usually 1.5~2ml per gallen more will be helpful. :circle-of-love: Plants under LEDs will need cal and mag badly. :volcano-smiley:
Hi Sara,
I'm in organic soil and nutes, so PH is not as much of an issue. Like I said, it's only 2 strains out of 18 that are a problem., so I just wont be running those 2 in future gardens. I'm using CalPlus organic and epsom salt, and it's working well on all the other plants. I keep my RH between 40-50% to avoid PM and bud rot. Is there some reason to run higher RH with LED's?
 
High Fed, thanks for your reply. FYI, usually during veg, if the RH is below 50%, the plants might get bleached. For the cal and mag, usually 1.5~2ml per gallen more will be helpful. :circle-of-love: Plants under LEDs will need cal and mag badly. :volcano-smiley:

I know this must be true for most as I have read it sooooooo many times but 12 pounds over the last 10 months and still no sign of it. I even dropped Epson salts out of the recipe since I have not yet seen it needed. Started Jacks 3-2-1 for a couple grows and slowly dropped the 1 (epson) to .5 to .25 now to zero. Last grow I used GH maxi last 4 weeks and koolbloom the last 2 ......best grow yet but still no cal mag needed .....and I use RO water.

Just my experience ...
 
With the volume of light that you are using, you shouldn't have any problems, if all other relevant factors are controlled. Some of your light intensity is being wasted unless you are using co2. HCS 1
 
I use the Mars 900 watt growing one Kush plant in a 4x4 scrog started flower with it about 28" above plant cause that was as close as she liked,then well after stretch it was 22" above canopy then moved it down to 18" and that's as close as she likes,used cal mag at 4ml per gallon ,here is a pic at day 60,whats your thought on LED development as far as flowering period does it take longer to flower or the same,
day_60_of_flower_00_KUSH_023.JPG
 
Since LEDs produce a superior full spectrum light with greater PAR, everything happens faster. The plant's biological clock is advanced a number of days and even weeks, so that the plants actually finish earlier and can be harvested faster. The plant looks very happy and the colas, awesome. One heads-up to you though - you have what appears to be a systemic leaf-tip burn, that you might want to diagnose before your next grow. It seems to be a nutrient issue. Good luck to you. HCS 1
 
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