lucas Formula with LEDs - wtf!?!

good idea?

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N

New2LEDs

Member
I have been growing with T5 in veg and HPS on bloom for over a decade. i just switched to LEDs... ( GC e420ROI & fluence SPYDRx in Veg ) and GC e4720ROI in bloom...

I used to use the 5/10 with GH flora series in veg under T5, the bump it up to the full strength 8/16 in bloom under HPS. never had issues. terps were amazing, the yields were good, and the smoke was great. i would ride the ppms to dial in the actual ppm for each table ( each table had 1 strain in it). if the rez started at 1000pm and after feeding it was 900, i would bump up the feed to 1100ppm. and i would adjust until each day the rex was at the same ppm as the test before.

so im having issues here... and im not finding the info i need. i tried the 5/10 with a 330w fluence spydrx fixture, adn i had to take off 2 of the 5 bars to achieve a 200-300umols ppfd in early veg. and it was to much. plants were locking out.... so i flushed and fed at 3/6 ( 510 -530ppm @.7 conversion on my blue lab ppm pen). i feed at 5.8ph

im starting to see red stems on my major fans ,adn quilting on my leaves...

i dont understand why i have to dilute the feed because of the type of light... i was advised to reduce the recipe by at least 30% for LED lighting versus HPS.... i thought i could run full strength it light was over 400watts, and i have not seen any chart that breaks down the feed ratio based on light intensity, or what stage the plant is in.... i.e week 1 of veg, or week 4 of veg.

fyi I veg at 200-300umols under the 300-400watt LED, then veg under a 400 watt led at about 400-600umols, and plant to flower at about 800-1000 umols under a 620-800w led fixture.

this LED issue and lucas is really messing with me.

or did i just assume i had to lower the ppm for LED, bc i was actually dealing with a light intensity issue?

the last run i had a cooler room ( 72F & 55%rh ) and vegged under t5 at 5/10ml ( 750ppm ) and it was all good. and bloomed at about 6/12ml (950ppm).

i was considering keeping it at 3/6ml ( 510-530ppm) for early veg ( 200-300umols), and bumping it up to 4/8ml ( 680ppm) under the 420 watt led ( 400-600 umols ), and bloom using 6/12ml ( 995ppm ) under the 720watt led ( 800- 1000umols)

ANYONE see any issue with this?
 
N

New2LEDs

Member
Jjgrow420 said:
Bring up temps to above 80.
Click to expand...
ty for the input. i am currently in early veg at 80F & 70-74% rh. planned to do the 400watt veg at the same temps and rh, and bloom at 78F with 65% rh do you believe that to be sufficient?

when you advise over 80... what temp should i shoot for in late veg and bloom?

again tyvm.
 
N

New2LEDs

Member
coreywebster said:
I've never heard anyone suggest lowering feed under LED.
Yes it's a light intensity / environment issue.
As in you need higher air temp to balance the increase in light intensity because you're not getting the radiant heat from your lighting anymore
Click to expand...
well you know it happens. ppl give bad advice on purpose. i wont throw the guy under the bus... but he did tell me to lower the feed rate.... also i saw a post where someone said bloom between 1.0 - 1.2 EC which is like 6M & 12B

so you can see why i am mislead, right?

thank you.
 
PopAndSonGrows

PopAndSonGrows

Well-Known Member
My general understanding of LED vs HID or T5 growing, is that plants under LED typically need a potassium boost? Can anyone confirm or deny? Or is it Magnesium?
 
N

New2LEDs

Member
OK. raising temps in early veg (200-300umols) and late veg (400 - 600umols) to 85F and 70-75%rh

should i feeding more in frequency, or increase the ppm from the current feed. when i see deficiency i want to add more food, since im vegging at 3/6 currently. SHould i just bump it to 5/10 from 3/6 and then run the full strength 8/16 in late veg and bloom? ive never had to deal with major deficiencies like this...

i appreciate all the help. thank you. please keep it coming. bc so far i beleive the temps will be correct, now jsut need to confirm the feed rate (ppm).
 
coreywebster

coreywebster

Well-Known Member
You probably can bloom at 1.0ec if your feeding 4 times a day. Ive never tried that low.
I have no idea what 6m & 12B means though.

New2LEDs said:
well you know it happens. ppl give bad advice on purpose. i wont throw the guy under the bus... but he did tell me to lower the feed rate.... also i saw a post where someone said bloom between 1.0 - 1.2 EC which is like 6M & 12B

so you can see why i am mislead, right?

thank you.
Click to expand...
 
N

New2LEDs

Member
coreywebster said:
You probably can bloom at 1.0ec if your feeding 4 times a day. Ive never tried that low.
I have no idea what 6m & 12B means though.
Click to expand...
should i raise my feed concentration to 5micro / 10 bloom for light intensity between 200-300umols and when i go over 400umols, i make the switch to 8ml micro & 16ml bloom. i ask becasue i used to veg un t5 at 5m/10bloom per gallon, and when i switched to hps ( over 400umols ) i was using th 8/16 recipe.
 
N

New2LEDs

Member
rkymtnman said:
the only thing important is the 1:2 ratio. and then run whatever EC the plants can handle.
Click to expand...
thank you. i appreciate the advice. youve been running lucas for a while too, it seems form your posts. did you switch it up to the head formula, or go back to the 8/16?
 
rkymtnman

rkymtnman

Well-Known Member
i never could get close to 8/16 without massive tip burn

i started with head when i switched to coco and am now trying a 4:3 ratio of micro/bloom which seems to working fine in coco.
 
curious2garden

curious2garden

Well-Known Mod
Staff member
New2LEDs said:
I have been growing with T5 in veg and HPS on bloom for over a decade. i just switched to LEDs... ( GC e420ROI & fluence SPYDRx in Veg ) and GC e4720ROI in bloom...

I used to use the 5/10 with GH flora series in veg under T5, the bump it up to the full strength 8/16 in bloom under HPS. never had issues. terps were amazing, the yields were good, and the smoke was great. i would ride the ppms to dial in the actual ppm for each table ( each table had 1 strain in it). if the rez started at 1000pm and after feeding it was 900, i would bump up the feed to 1100ppm. and i would adjust until each day the rex was at the same ppm as the test before.

so im having issues here... and im not finding the info i need. i tried the 5/10 with a 330w fluence spydrx fixture, adn i had to take off 2 of the 5 bars to achieve a 200-300umols ppfd in early veg. and it was to much. plants were locking out.... so i flushed and fed at 3/6 ( 510 -530ppm @.7 conversion on my blue lab ppm pen). i feed at 5.8ph

im starting to see red stems on my major fans ,adn quilting on my leaves...

i dont understand why i have to dilute the feed because of the type of light... i was advised to reduce the recipe by at least 30% for LED lighting versus HPS.... i thought i could run full strength it light was over 400watts, and i have not seen any chart that breaks down the feed ratio based on light intensity, or what stage the plant is in.... i.e week 1 of veg, or week 4 of veg.

fyi I veg at 200-300umols under the 300-400watt LED, then veg under a 400 watt led at about 400-600umols, and plant to flower at about 800-1000 umols under a 620-800w led fixture.

this LED issue and lucas is really messing with me.

or did i just assume i had to lower the ppm for LED, bc i was actually dealing with a light intensity issue?

the last run i had a cooler room ( 72F & 55%rh ) and vegged under t5 at 5/10ml ( 750ppm ) and it was all good. and bloomed at about 6/12ml (950ppm).

i was considering keeping it at 3/6ml ( 510-530ppm) for early veg ( 200-300umols), and bumping it up to 4/8ml ( 680ppm) under the 420 watt led ( 400-600 umols ), and bloom using 6/12ml ( 995ppm ) under the 720watt led ( 800- 1000umols)

ANYONE see any issue with this?
Click to expand...
I'm in a similar place. I'm coming from HID to LED in flower for my first time and I'm having to heat my grow! Something I've never had to do with all the excess thermal energy from my HPS even in air cooled hoods.

LED is more efficient light which means we lose the side effect of heat, ie our HID's were both heater and light source. Now we have a better (more efficient light source) we have to add in the heat they need to drive their metabolic processes that was previously provided by our lights.

NB: try for a leaf temp of 85
Good luck
 
N

New2LEDs

Member
curious2garden said:
I'm in a similar place. I'm coming from HID to LED in flower for my first time and I'm having to heat my grow! Something I've never had to do with all the excess thermal energy from my HPS even in air cooled hoods.

LED is more efficient light which means we lose the side effect of heat, ie our HID's were both heater and light source. Now we have a better (more efficient light source) we have to add in the heat they need to drive their metabolic processes that was previously provided by our lights.

NB: try for a leaf temp of 85
Good luck
Click to expand...
awesome. ty
giphy.gif
i now have early veg at 84-85F and 70-74%rh

now i will just have to play with concentration of nutes. im at 3ml of micro and 6ml of bloom ( 510-530ppm @.7 ) and find the sweet spot for each strain in early , late veg and bloom... the journey continues!
 
Last edited:
N

New2LEDs

Member
Leaf temps sorted... plants seem to be praying and have perked up. thanks for the assistance on that....

now question #2: hopefully last question :)
Lucas Formula - GH flora series Micro (M) & Bloom (B) as I used it in the past and did some advice back in the day from both Ph and H3ad.... i ran 2M/4B on seedlings and clones that have just sprouted roots. then i get them on 5M/10B under T5 between 100-200PAR. and i used the same 5/10 recipe for all T5, even under the early veg flora lights putting off like 400PAR.. and i would only switch to the 8M/16B recipe when under a 600w or 1000w HPD or DE HPS...

Under LED
i was considering keeping the feed at 3M / 6B ( 510-530ppm) for early veg ( 200-300PAR), and feed 2 times a day and bumping it up to 4 Micro / 8 Bloom ( 680ppm) under the 420 watt led ( 400-600 umols ), and feed 2-3 times a day, and flower using 6/12ml ( 995ppm ) under the 720watt led ( 800- 1000umols) i would feed 3-4 times a day in bloom

in flower i would lower my humidity to 65% to match the late veg humidity levels, for an easy transition to bloom.

ANYONE see any issue with this? if so what do you advise?
 
N

New2LEDs

Member
oh yeah... im running a hydro drip system, recirculating, rockwool. i know what some say aot rockwool.... but i hate the mess of dirt in doors, i don't want the waste of coco, and i can remove more squished up cubes than i can dirt. living soil is a want in the future. just not here, not right now.
 
Crazy4coco

Crazy4coco

Member
This has been my first LED grow and I chased my tail some . I see no need to lower your ppm once they are out of seedling stage . I run 6/9 for veg and found cal mag is a must with the LED . I switch to bloom only during flower and just add bloom only nutes during flower adjusted to 750 ppm and feed twice a day . I still add some cal mag once a week at 5 ml per gallon . I’m in coco drain to waste in net pots . Next run I plan to foliar feed epson salt as well . I used quality bag coco and buffered before use . I know the LED is causing some cal mag issues as I put half the grow on a 600 HPS and they look night and day compared . Watch how close you get those LED I fried some plants from too much light . LESSON LEARNED !
 
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