The Grow Awards 2026 🏆 
Lightning timeline for auto flowers under LED
torgul2000started grow question 3y ago
For the automatic varieties (Skunk #1 Auto, Hindu Kush Auto and Pure Power Plant Auto), what is the best technique for growing under LED in terms of light time: 12/12, 18/24 or 20/24?
likes
Answer
ernest_twwganswered grow question 3y ago
I've been growing my Bruce Banner auto at 18/6 the whole time and it has been rocking socks.
1 like
Complain
SlowpokeFuegobudanswered grow question 3y ago
Hi! Make sure you got the right DLI, that is the total amount of light they get per day.
So stronger LED can be 18h and have the same DLI than a weaker one over 20h.
To take a look at the climate in the room is a great idea!
Happy growing!!
1 like
Complain
Hashyanswered grow question 3y ago
During the colder months I Run 20/4 as temps get low with lights out, during warmer months I go 18/6. That's all the way from seed to harvest. As organoman said its best to let them have a rest period.
1 like
Complain
Organomananswered grow question 3y ago
18 hours of light and 6 hours of dark.
All cannabis planys NEED sleep to finish their photosynthesis cycle and have a correctly functioning metabolism.
Cannabis can only grow so much during any one 24 hour period and this growth tops out at around the 18 hour mark, meaning running your lights any longer than 18 hours is basically a waste of electricity.
NEVER grow at 24/0!
1 like
Complain
Similar Grow Questions
Solved
studente
LightingWow. Thank you so much for the reply. I have been playing with LUX meter app and my light. I was bit skeptical about the lumens that I would get from the 15W but as it turns out, it receives well enough ppfd. Still skeptical about the spectrum i am having.Week 2
Setup. Lighting
6y ago
1
1
Solved
hollyhustler
Is that just a light burn or could it be something else?One bud in the middle of my plant is much lighter than all the others, which all look healthy and green. I think it was due to the too small distance of my light, which was only 20cm (8") between canopy and light. I have now moved the light to 35cm (14").
What are your opinions?5y ago
4
3
Solved
BBhykiem1
Start over or see this beast till it's end?been weeks since it showed it first pistils and not much more, Roots fine, 24hr light time now at 100 watts due to light burn which I can't raise anymore, eats/drinks a gal a day on full strength nutes, ph 6.3, temp 65, humidity 50 -55 Gsc auto from garden of green seed bankPlant. Too tall
Setup. Lighting
Techniques. Defoliation
3y ago
1
18
Solved
Humble_Lion
How to reveg plants after preflowers by the end of april outdoors?How big are the chances to bounce the plants back to veg after preflowers by the end of april and 14h of day length? Mostly cloudy weather, warm day temperatures (30c) and cooler nights (8c)in the old greenhouse simulated probably to much end of summer vibes.3y ago
6
6
Solved
MangJs
HLG 350R or ES300 V3 ??Hi Growmies,
planning on adding an additional light on my 4x8 I currently have 1x HLG 650R running, but need your opinion if I should go for HLG350R or ES300 V3 ( Green sunshine Co ) whats your thoughts? i want to leave quarter space inside to work on and also to put some equipSetup. Lighting
5y ago
3
3
Solved
QuiGonJib
Almost doneThis is our first grow and we are in week 6 of bloom. Does anyone have an idea for the brother in the picture. He grew above the lights. We not sure how to handle it. Two leaves are to close to the light and turned yellow. Should we cut them away or leave them on itLeaves. Color - Yellow
Setup. Lighting
4y ago
1
2
Solved
Growladyeastmidlands
What light is best for autosI have 8 seedlings and I am using a waykem 600w led at present but I need help to know what light best to use and when to give them more light I have 3 x 600w hps a marshydro 1600w led and a king plus 1500w led and 2x waykem 600w led can anyone help pleaseSetup. Lighting
4y ago
3
10
Solved
Lew420
Opinions on progressSo this is my first solo grow in a completely new setup (previously only grown in collaboration with a friend). Started off with a cheap blurple light. Very slow start then upgraded to a mars hydro TS1000 2 weeks prior to flowering.
Topped at 35 days
How is she looking?3y ago
1
2
Solved
DoDrugs420
Wich of those cheap lights would be advised under 200€ and that would fit both final vegging state and flowering?
The grow space is 80cmx80cmx160cm and keeping in mind that the weather along with the lack of ventilation budget limits my options to colder leds.
Thanks in advanceWeek 1
Setup. Lighting
6y ago
10
10
Solved
DanDec
Switching light schedule for an auto and Phototype!I'am growing together an auto and a phototype with 20/4 light circle. For my phototype is about time to change light schedule for flowering, will my auto be badly impacted by switching to a 12/12 light? Or should I move every day (same place but no light) the photo for the night?Setup. Lighting
6y ago
2
3
