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LED bulb distance from plants?

Gantz

Gantz

Smoke weed and prosper
Veteran
I've been watching the micro forum like crazy and i'm already building a growbox. As soon as it is ready I will post pictures of it, but for now I'm working on a few finer details.

The box is going to be 40cm x 40xm x 85cm and i'm going to put in 8 x 10W led bulbs.

I know it's tall - and that is by design. I might change something in the future.

Anyway. How close should my plants be from the lights, and at what stage of their development? The hand method is cute but i'd love a distance in cm or inches.

So how close do you keep your seedlings, vegging plants and flowering plants to your ledbulbs? Where is the sweet-spot? And where is the lightburn-spot?
 
Bird of Hermes

Bird of Hermes

Member
I had light burn when i had them 4-6 inches away and looked this up pretty extensively. From what i gather from multiple sights and forums its 12-24" with most staying in the middle of that range around 16-18".
 
R

roflio

Member
Heavily depends on the lamp being used. I have a 130W LED and had plants literally touch it without getting burned. Then again you can find horror stories of plants getting fried at beyond 10cm.
 
Douglas.Curtis

Douglas.Curtis

Autistic Diplomat in Training
Depends on the wattage of the individual LEDs, I'm sure. I have a GE 15w screw-in with 14 LED chips on it, where most other screw-in brands I've seen are using 30+... I definitely keep the GE further away. ;) It's part of an array though and I haven't had enough testing to give distance numbers yet.
 
Gantz

Gantz

Smoke weed and prosper
Veteran
Thanks mate. I had found that a little while after posting the thread.
I was just hoping this would attract some of the others that have inspired us so.
The growbox is fine. I'm working on installing the ventilation and panels. Then all i have left is to put the lighting in and once i'm satisfied with the light traps and ventilation I'll give it a coat or two of white paint and i should be ready to grow.

it's slow going because i have a lot of other stuff to deal with
 
A

Athos

Member
I just put together a box with dimensions very similar to yours (originally it was gonna be 85 cm high, upped to 100 cm, to make space for a carbon filter). I have 6 x 10,5 Watt 6500 K Phillips in there.

Anyway, I have a couple of seedlings that germinated in soil and I started them 3 inches (7,5 cm) below the lights; 1 week after they broke soil, they showed signs of heat stress once the seedlings were 1 inch tall, making the distance to the light 2 inches, which proved too much; I moved them back and the distance is now 4 inches to the lights and they are fine again,
 
Gantz

Gantz

Smoke weed and prosper
Veteran
Thanks for stopping by amigo. I'll be using similar lights so I'll follow your grow and learn from it. Drop a link if you have one.
Cheers
 
Gantz

Gantz

Smoke weed and prosper
Veteran
For anyone still reading this.

Here's a list of what some successful Led bulb growers are saying:

El Tigre uses 8x13W and says that
Lower Powered LEDs
Seedling: 15-20 inches| 38.1 - 50.8cm
Vegetation: 15 inches| 38.1cm
Pre-flower: 10-12 inches| 25.4 - 30.48cm
Flowering: 8-10 inches| 20.32 - 25.4cm

and

Terpene has posted this lovely image
picture.php
 
A

Athos

Member
Yo Gantz.

I read a lot other people experiences too, trying to determine the optimal distance.

The best advice I can give you with my limited experience is to get your feet wet and try it in your own micro grow, your temperatures will be different than mine and so will be your results

The only conclusion I made it's that every system is different. The only constraint regarding how close to keep the plants to the light at a given stage is the temperature at the canopy.

I tried different distances, from 2" to 12". So far, the best distance has been 3 or 4 inches, regardless of the stage. At 2 weeks old that distance gave seedlings 2 inches tall with 5 pair of leaves.
 
Douglas.Curtis

Douglas.Curtis

Autistic Diplomat in Training
Terpene's chart is only accurate for the lamps it was created with. :(

The problem I see with LED screw-in LED's and "standards" for distances comes down to the mfg decisions made by the company. A 15w led, made from 14 cob bits, is going to be more effective at a greater distance than one made with 26 or 34 cob bits. I'm seeing mostly 1w and .5w (approximate wattage) led's being used on various models and brands.

Know what I mean? :)
 
BReal

BReal

Active member
"Seedling: 15-20 inches| 38.1 - 50.8cm" It's half of the space I have :laughing: The distance between these dark pots and the light is 75 cm. I'm using one CXB3590 powered by 1.4 A current (~50W) and I already have small problems with my babies which were about 60 cm from the light source so I moved them down a little bit. I'm not fully sure if it's because of the light source being too close but symptons look familiar - you won't notice that but I spotted a few very microscopic areas on the leaf's edges which has brown colour. I'm afraid what would happen later when they will grow bigger :bashhead:

picture.php


picture.php


Should I install dimmer/power supply with lower current or leave it and see what would happen later? Because I can't adjust height :/ And I'm not sure if it's a problem of the light or smth else. Very strange is that Bueno Time had a very familair setup to my (almost identical) and he didn't have any problems with light burns :thinking: He had CXA3070 COBs which are only slightly less efficient.
 
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Gantz

Gantz

Smoke weed and prosper
Veteran
Can't help you there bud. I'd want to bring them closer but I get it. You're afraid you'll kill'em.
Have you tried searching the light you're using?:tiphat:
 
BReal

BReal

Active member
Ok... I saw another grow with two of these cobs in a shorter box and there were no signs of lightburns, so the problem is something else :thinking: actually I could bring them closer to light as it is only one led. I've made a mistake because I invested in Cookies Kush of Barney's Farm and as I have heard recently this breeder has bad reputation: ppl are complaining on very slow veg and males who shouldn't appear (fem seeds). It was a bad choice probably. I should look for strains from any other breeder. Well... 1st indoor grow mistakes. Sorry for panicking. My post doesn't fit this thread in that case, hehe...
 
T

thenewstyle

Active member
BReal said:
Ok... I saw another grow with two of these cobs in a shorter box and there were no signs of lightburns, so the problem is something else :thinking: actually I could bring them closer to light as it is only one led. I've made a mistake because I invested in Cookies Kush of Barney's Farm and as I have heard recently this breeder has bad reputation: ppl are complaining on very slow veg and males who shouldn't appear (fem seeds). It was a bad choice probably. I should look for strains from any other breeder. Well... 1st indoor grow mistakes. Sorry for panicking. My post doesn't fit this thread in that case, hehe...
Click to expand...

were those seedlings born under those lights? i would def add a dimmer, run around 700ma while theyre small and slowly ramp up to full power as they get bigger. +5w per node
 
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