[dddaver]

I have a little 150 HPS but it gets wicked hot down south heeya, so I went LED. First I went with a 90W UFO, then 180W UFO, now 240W Blackstar. Every LED grow took longer for trichs to go amber. Current grow at 10 wks advertized to finish at 8 and still no amber. All my LED grows took longer. I'm thinking it's inherent in using LEDs to grow. Is it?

[PaullyHighBred]

Inherent in the leds themselves? No. Inherent to allot of commercial panels? Absolutely.
I have a feeling your panels maybe lacking 730-750nm spectrum. This isnt an inherently bad thing, if you can afford the patience. In fact I think this part of the reason growers often report higher gpw's and frostier buds with leds. The plants continue to grow while taking longer to finish packing on weight and frost without heat stress.

A simple test would be to add halogen light to the end of your flowering daycycle. Like 11 hours led, 1 hour halogen 12 hours darkness.

Based on my own subjective experiments I've found this light cycle to shave roughly 2weeks flowering on my indica dom cuts and nearly a month on sativas with my DIY led panel and the addition of halogen at the end.

heres an article that may help https://users.rcn.com/jkimball.ma.ult...periodism.html

-PHB

[Phaeton]

I have found that pounding the plants hard with extra blue speeds ups harvest times, more in sativa than indica. This also makes the plants smaller.
The HGL lights in the 12/12 room are 10% blue, used alone takes a week longer to bud, big frosty buds they are. An equal wattage surround mostly blue and UVB gave that week back, and took over 10% of the size also.
The Magnum lights in the 18/6 room are 30% blue, nice solid plants easy on stretch. Time will make them any size wanted. Still have a UVB/blue surround, plants just grow differently with a high power sidelight.

Spectrum and intensity on the leaf make the difference in bud timing. The plant does not care what the source is. Some sources are less expensive than others. Quite often this is the determining factor.

HGL Pro and Magnum Plus both have deep red, 740 nm and 730 nm respectively, both are costly.

The advice was going to be use both the HPS and the LED aimed in one on each side of the top.
Then I saw this is a heat problem. Oh darn 'cause HPS and LED is a killer combo.

[VerdantGreen]

yeah my HGL's have quite a bit of far red and i find that they finish a bit quicker than HPS.
adding extra far red was one of the changes thay made when they went to their 3rd generation spectrum a year or so ago. far red is also reputed to increase tric density

older LED's i used with a less dialled spectrum definitely take longer.

VG

[analogue]

Another thing to consider is the temperature. When I switched from a 150 watt HPS to LEDs the cabinet temps dropped 10 degrees Fahrenheit. Too cold.

I increased the temperature from 70 or below, to 75-80 F.

[grow_right]

with my led lamps, i have not noticed any lengthening of over all finish time.

[jessicalennita]

It definitely depends upon the temperature but LED lights are most advisable because of their unique features that can give light which the plant requires and helps to grow healthy and effectively. It may take some time at first but later shows the results.

[siddhartha]

My strains have stayed the same for finishing time. One thing to remember is plants metabolism is linked to temperature. lower temps slow down metabolism, but temps above 95 stop growth all together for most plants because of inability to synthesis protein at that temp. So if you had HPS and your room temp was at the perfect 80 degrees and you switched to LED and your temp went down to 75, your growth and finish time would slow.
Now lets say you switched to LED in the middle of June, and you are stocked because you can still run your grow but your temps hit 96 degrees for 4 hours a day, or even worse, during the lights off period, your plants are alive and still growing but have slowed growth down because of the high temps. So finish time would be pushed out a few weeks.

Sidd