Moving from HPS to LED Bars, what's your experience?

[Trash_2002]

Finishing my first run with leds flexstar 645w bar style.

Observations:

- Plants under LED doesn't "eat" more than with hps that's a busted myth , but yes they could benefit from extra cal/mag

- Plants under LED transpire less even with proper air temperature for LEDs without CO2 (78-82f/25.5-27.5c).

- Because of reduced transpiration it's a good idea to use airpots or fabric pots so the drybacks are a bit faster.

- On cold days it can be a little hard to maintain a proper air temperature so I installed tent fans on the roof mixing better the hot air back on plants, it works pretty good for my environment, they like it.

- I will start next flowering with lights at 60% (380w) at 1.2m from canopy, first run with it at 80% for the first two weeks was too much. Will increase to 80%@60-80cm from canopy only at week 3-4 after the stretch phase.

- LEDs do make plants magnesium starved (purple petioles and stems on cultivars that don't have it genetically), didn't had a problem with calcium, but I believe it's good practice do use cal/mag from start to finish (EC 200uS seems to be enough), before adding the base nutrients to the reservoir.

- LEDs produce denser nugs, bring out colors much easier than HPS, it also brings out more terpenes concentration in the buds, trichomes are bigger with longer stalks and better formed under LEDs. The trichomes hypothesis I still have to confirm, could be caused by the light stress they suffered this run but I doubt it.

If I find anything further in the future I post here.

 

[MEGA956]

Finishing my first run with leds flexstar 645w bar style.

Observations:

- Plants under LED doesn't "eat" more than with hps that's a busted myth , but yes they could benefit from extra cal/mag

- Plants under LED transpire less even with proper air temperature for LEDs without CO2 (78-82f/25.5-27.5c).

- Because of reduced transpiration it's a good idea to use airpots or fabric pots so the drybacks are a bit faster.

- On cold days it can be a little hard to maintain a proper air temperature so I installed tent fans on the roof mixing better the hot air back on plants, it works pretty good for my environment, they like it.

- I will start next flowering with lights at 60% (380w) at 1.2m from canopy, first run with it at 80% for the first two weeks was too much. Will increase to 80%@60-80cm from canopy only at week 3-4 after the stretch phase.

- LEDs do make plants magnesium starved (purple petioles and stems on cultivars that don't have it genetically), didn't had a problem with calcium, but I believe it's good practice do use cal/mag from start to finish (EC 200uS seems to be enough), before adding the base nutrients to the reservoir.

- LEDs produce denser nugs, bring out colors much easier than HPS, it also brings out more terpenes concentration in the buds, trichomes are bigger with longer stalks and better formed under LEDs. The trichomes hypothesis I still have to confirm, could be caused by the light stress they suffered this run but I doubt it.

If I find anything further in the future I post here.

Great observations. I second that mag turning stuff purple. I have a few different brands of led it's nice to see the difference between them.

 

[Trash_2002]

Finishing my first run with leds flexstar 645w bar style.

Observations:

- Plants under LED doesn't "eat" more than with hps that's a busted myth , but yes they could benefit from extra cal/mag

- Plants under LED transpire less even with proper air temperature for LEDs without CO2 (78-82f/25.5-27.5c).

- Because of reduced transpiration it's a good idea to use airpots or fabric pots so the drybacks are a bit faster.

- On cold days it can be a little hard to maintain a proper air temperature so I installed tent fans on the roof mixing better the hot air back on plants, it works pretty good for my environment, they like it.

- I will start next flowering with lights at 60% (380w) at 1.2m from canopy, first run with it at 80% for the first two weeks was too much. Will increase to 80%@60-80cm from canopy only at week 3-4 after the stretch phase.

- LEDs do make plants magnesium starved (purple petioles and stems on cultivars that don't have it genetically), didn't had a problem with calcium, but I believe it's good practice do use cal/mag from start to finish (EC 200uS seems to be enough), before adding the base nutrients to the reservoir.

- LEDs produce denser nugs, bring out colors much easier than HPS, it also brings out more terpenes concentration in the buds, trichomes are bigger with longer stalks and better formed under LEDs. The trichomes hypothesis I still have to confirm, could be caused by the light stress they suffered this run but I doubt it.

If I find anything further in the future I post here.

i ended upping calmag to ~350uS this second run and they are thriving :-)
with LEDs there's a tendency to have K def/lock but upping my flower booster sooner cleared it pretty fast too.

 

[Trash_2002]

another thing i learned, in flower LEDs too far away from canopy is no good, with it closer and properly dimmed a proper leaf surface temperature (77f/25c) is much easier to achieve and they really like it. I suspect most mag and K problems with led is because of low LST.
With HPS this was so much easier to achieve.

 

[JKash]

Finishing my first run with leds flexstar 645w bar style.

Observations:

- Plants under LED doesn't "eat" more than with hps that's a busted myth , but yes they could benefit from extra cal/mag

- Plants under LED transpire less even with proper air temperature for LEDs without CO2 (78-82f/25.5-27.5c).

- Because of reduced transpiration it's a good idea to use airpots or fabric pots so the drybacks are a bit faster.

- On cold days it can be a little hard to maintain a proper air temperature so I installed tent fans on the roof mixing better the hot air back on plants, it works pretty good for my environment, they like it.

- I will start next flowering with lights at 60% (380w) at 1.2m from canopy, first run with it at 80% for the first two weeks was too much. Will increase to 80%@60-80cm from canopy only at week 3-4 after the stretch phase.

- LEDs do make plants magnesium starved (purple petioles and stems on cultivars that don't have it genetically), didn't had a problem with calcium, but I believe it's good practice do use cal/mag from start to finish (EC 200uS seems to be enough), before adding the base nutrients to the reservoir.

- LEDs produce denser nugs, bring out colors much easier than HPS, it also brings out more terpenes concentration in the buds, trichomes are bigger with longer stalks and better formed under LEDs. The trichomes hypothesis I still have to confirm, could be caused by the light stress they suffered this run but I doubt it.

If I find anything further in the future I post here.

Phlizon fd 6500... I've noticed better trichomes compared to my 1000w hps setup

 

[Natep]

I keep a heater in my tent to help keep temps right

 

[JKash]

I keep a heater in my tent to help keep temps right

So depending on where you are I have 2 inline fans in my tent... cold air blowing in at bottom and heat exhausting out top... really helps circulate air

 

[Porky1982]

Curious to see what experienced LED's growers think about it in Flowering stage:


Witch media do you use ?

How Much is your watering frequency ?

What's your Canopy Temperature/Humidity Range ?

What's your max Canopy PPFD ?

What's your VPD target ?

What's your EC Range ?

Do they Drink/Transpire more or less under LEDs ?

Do you feed more or less EC with LEDS ?

cheers!!!

Plants hight was the major difference I have four and strech seems to be much less than HID.
I find some strains want more magnesium and others want more calcium than with HID.
Buds seem to be thicker and more dense than HID. This coincides with the plants size and structure though!