Anyone have experience with the Samsung lm301b grow lights? Plant health...

[Milie]

Hello, 

I need some help with my current indoor grow. I'm using 2 x 220w LED boards using Samsung LM301B diodes(pretty popular light these days) and burnt my plants from them being too close. I've since moved the lights up and the plants are starting to respond to it better. Have you used said lights/diodes before, what advice or lessons did you learn about the growing period, i.e. distance for the lights, number of plants grown, yield, grow space etc. would be greatly appreciated. 

Thanks,

PS: I'm not a new grower, started growing about 6 years ago outdoor, then moved to a CFL indoor grow the next year as well as outdoor and stopped for about 3 years. So I'm getting back into growing and first time using LED. 

 

[PsyCLown]

Hey Milie!

 

Welcome to the forum.

 

I also use Quantum Boards with LM301B diodes - excellent lights! I love mine

You can burn your plants with LEDs if the lights are too close to the plants. As for the hanging height, there are lots of variables and your growing conditions might differ from mine so it is hard to say unless things are evened out.

 

The watts you have your lights dimmed to will affect the height significantly.

Also you may have fewer plants and therefore are happy to run them lower and at a lower wattage to ensure light is not "wasted" by ending up reflecting off the side walls of the tent type of thing.

 

Typically 30cm to 45cm is a decent height to have your lights above your plants, you can move them higher up too if you need a better spread but the further away the light is from the plant, the lower the concentration of the light is which the plant receives.

I for one prefer to run my lights rather close to my plants and have on multiple occasions run them lower than 30cm above the plants.

 

If you give us a bit more detail on your setup, such as how big your tent is and whether you are using the full space of the tent, then perhaps we can provide you with a bit more specific recommendations.

[SkunkPharm]

It all depends on the heat the light puts out. The actual light that is emitted will not burn the plants. I have plants 5cm away from my light no issues.

Edited December 1, 2020 by SkunkPharm

[Prom]

^^ Follow the guys before.. you might need to increase your ventilation inside the tent by quite a bit.

If you have 288 QBs, 30 cm is close and the closest part will not be able to use all the light you give it.. except you run a additional CO2 generator. 

As @SkunkPharm said, is hard to burn with LED, as the head radiation is very low.. not zero but should't get hot enough to actually burn your plants. If your boards get so hot, that they emit strong heat radiation, you have a cooling issue on your QBs.. hand warm they run efficient, the hotter they get, the more inefficient they run. If you can't touch them, you need cooling.

[SkunkPharm]

I run an oscillating fan just on my lights. Helps with cooling them thus they will last longer.

[Milie]

Hello everyone,

Thanks for all the replies. I'm very nooby with LED lights as its my first grow with them. So a little more information; I definitely didn't have enough ventilation when I started growing my plants indoors under the lights. (I germinated and started them indoors/outdoors with natural light until they were about 10cm big and then moved them under the LEDs. The room stayed around 27 - 30c with 50%-65% humidity. Definitely too much heat but humidity was ok. I had a fan on the ground and that was it. The plants looked fine for the first 2 weeks thereafter the leaves started going very yellow and shriveling up, only top leaves mind you. Which indicated to me that they were being burned by the lights as I've been using the BioBizz grow once a week and have used cal-mag substitute once. The plants were about 30cm away from the lights tho and the lights don't get very hot but the intensity of those diodes are very strong.

 

Current setup:

Room size: 2.2 m2 

6 plants about 4 weeks into grow.

Nutrients: BioBizz Grow, bloom, seagrow, cal-mag and co2 tabs.

Medium: Natural medium from Freedom farms (Coco, perlite etc.)

Lights: 2 x 220w Samsung lm301b diodes with meanwell driver currently hung about 50cm from plants.

I've since added an inline extractor clearing the room air in about 2/3 min and an oscillating standing fan.

The plants appear to be recovering but very slowly. Some green is coming back to the top leaves that weren't completely burned. 

Any other info would be much appreciated. Thank you for all the replies again. I used to be frequent on weed.co.za but it got shut down  and I never joined another local forum. Glad its as friendly here as it was there.

 

[Milie]

@PsyCLown Thanks for the reply. Glad to know you're having great success with the boards. I purchased them because the stats/specs looked great compared to other similar boards(not COBS). I Started them about 25-30cm above my plants but ended up burning them. I think because of the combination of the grow room being too hot with not enough ventilation and the lights being too close. I'll try add some pictures of how they looked before versus now. 

I've since moved them up to around 50cm and added ventilation and better air circulation. Temps now sitting at around 27c with 40 - 50% humidity but overall much better air flow. I'm hoping I didn't stress them too much or stunted their grow. Much easier growing outdoors/stealth box lol.

[Milie]

@Prom I'm running the 220w Hydrodepot LM301B full spectrum LED 

[Prom]

When they are running, can you put your hand on and leave it on? Or getting to hot to touch? Endless board configurations and they all dont work, if they get to hot and you have your plants to close. Even if your plants should touch your boards, they shouldnt get crisp 

the cooler your lamps run, the more efficient they operate, heat forms resistance. Can you post a pic how you run them?  In any case, dont go closer as 30cm. No real need to really go closer, you just smaller your footprint. I keep my 288 QBs at 40cm distance for flower 

[Milie]

@Prom they're hot but not hot enough for concern I think? I can touch them for a good 20 seconds before they start to get unpleasant. If its not the lights, do you think it was the grow area that was too hot? 

[Prom]

7 minutes ago, Milie said:

@Prom they're hot but not hot enough for concern I think? I can touch them for a good 20 seconds before they start to get unpleasant. If its not the lights, do you think it was the grow area that was too hot? 

You should be able to leave your hand on... you run to hot. 2 options.. more direct air on the lamp or better passive cooling, or a dimmer and reduce the input by a little. Tent temperature you have to check not to go over 26.. terps will suffer otherwise. Over 30 is baaaaaaad ^^ 

You have me a link to the lamp? Not sure I looked at the right place, couldn't find it.

 

[Milie]

@Prom

It's this one

It's been pretty hot today and the temp has been sitting around 28 or so. I'm probably going to insulate the roof so that it controls the heat a bit better. I'm growing in an outdoor room built into the building with canvas covering. So basically a room/tent hybrid. Lol. Been difficult to control compared to a tent. But we getting there. 

As for the heat on the lights, I'll run another fan directly on it suggested above to see if I can get them cooler. 

 

Edited December 2, 2020 by Milie
Adding an @

[Prom]

7 minutes ago, Milie said:

@Prom

It's this one

It's been pretty hot today and the temp has been sitting around 28 or so. I'm probably going to insulate the roof so that it controls the heat a bit better. I'm growing in an outdoor room built into the building with canvas covering. So basically a room/tent hybrid. Lol. Been difficult to control compared to a tent. But we getting there. 

As for the heat on the lights, I'll run another fan directly on it suggested above to see if I can get them cooler. 

 

Good light, stick to 30cm distance for flower. Nothing should suffer if you keep your room temp ok.

[Milie]

1 hour ago, Prom said:

Good light, stick to 30cm distance for flower. Nothing should suffer if you keep your room temp ok.

Awesome. I have two of them and judging from the umol output, it should be good for my size grow room? At least I hope so but obviously it depends on the amount of plants and how they're grown. Thanks for the help, much appreciated. 

[Prom]

with those two lamps you can easy run a 1.2x1.2 grow space during flower

[CreX]

18 hours ago, Milie said:

@Prom

It's this one

It's been pretty hot today and the temp has been sitting around 28 or so. I'm probably going to insulate the roof so that it controls the heat a bit better. I'm growing in an outdoor room built into the building with canvas covering. So basically a room/tent hybrid. Lol. Been difficult to control compared to a tent. But we getting there. 

As for the heat on the lights, I'll run another fan directly on it suggested above to see if I can get them cooler. 

 

i just checked and these are not the standard QB288 boards. these boards are made smaller to make them a bit cheaper.

QB288 layout is 16 diodes by 18 diodes to get 288 diodes on a board.

These lights are 13 diodes by 18 diodes, which is 234 diodes, roughly 20% less diodes per panel.

factoring that into the equation, i would say those lights will be solid for a 1x1 area

i see you mentioned your tent in sqm, 2.2sqm, which sounds like a 1.5x1.5 size tent?

if you could get an additional light set like that, or from another supplier, then i rate you will have decent light for your 1.5.

[Milie]

@CreX thanks for the reply. I'm a little confused, hopefully you can help clear some things up. By diodes, you mean individual leds right? If so then 234 is correct but each board is double that because that's just half of the board? I'll add a pic.

I have 2 of these boards.

 

[CreX]

2 minutes ago, Milie said:

@CreX thanks for the reply. I'm a little confused, hopefully you can help clear some things up. By diodes, you mean individual leds right? If so then 234 is correct but each board is double that because that's just half of the board? I'll add a pic.

I have 2 of these boards.

 

Correct, by diodes I mean each little light on the PCB. 

So a single Qb288 has 288 diodes on it, and not 234.

So your fixture is 234x2 which is 468 diodes, where a double QB fitting would be 288x2 which is 576 diodes. 

The lower price reflects 20% drop in diodes, so it's not a bad deal. 

But you can get the standard sized qb288s from some of the suppliers on this site at a very similar price, if not better priced. 

[Milie]

7 minutes ago, CreX said:

Correct, by diodes I mean each little light on the PCB. 

So a single Qb288 has 288 diodes on it, and not 234.

So your fixture is 234x2 which is 468 diodes, where a double QB fitting would be 288x2 which is 576 diodes. 

The lower price reflects 20% drop in diodes, so it's not a bad deal. 

But you can get the standard sized qb288s from some of the suppliers on this site at a very similar price, if not better priced. 

Ok thanks. I'll keep that in mind when buying lights/upgrading in the future. Thank you so much. 

So the 2 of these boards (936 diodes total) would be fine for my area? 

[Prom]

Son of a friend runs the same light, he uses one in a 1.2x0.6.. result is good for the fertilizer he used 

My TS3000s also have less diodes compared to 4 288 QBs, still work fine on a 1.2x1.2. I would use more wattage per area as diodes per area. Still want to try how much i get out of 360 watt, 3 288QBs on a 1.2x1.2. Grams per watt could go up, just always takes 3 months to run a test to answer one question. 

@Milie just keep your distance and you get a good footprint, pack your grow space and have enough ventilation on each plant.  keep us posted.

Edited December 3, 2020 by Prom
Typos, the usual

[CreX]

1 hour ago, Milie said:

Ok thanks. I'll keep that in mind when buying lights/upgrading in the future. Thank you so much. 

So the 2 of these boards (936 diodes total) would be fine for my area? 

still not sure what tent you have?

if you have a 1.5x1.5 tent, you will be running short on light and will need more to fully utilize your space, but not the results wont be terrible either.

the power is in the diodes! and they are good diodes! so dont fret about the lower diode count... it really only affects your grow footprint , not the output

[Prom]

21 hours ago, Milie said:

I'm growing in an outdoor room built into the building with canvas covering. So basically a room/tent hybrid.

 

Not a tent.. grow space.. 

[Milie]

@CreX 

I was initially looking at umol and wattage but obviously wanted decent quality diodes thus chose Samsung's offering. I've seen good things about them.

I'm only growing around 6 plants for now in that area. It's a grow space (thanks @Prom ) of about 1.2m x 2m width. I think I could probably sog about +10 plants in there maybe needing more light? I have 440w and was thinking of maybe adding a 50-100w cob if I went that route in the future. 

[PsyCLown]

5 minutes ago, Milie said:

@CreX 

I was initially looking at umol and wattage but obviously wanted decent quality diodes thus chose Samsung's offering. I've seen good things about them.

I'm only growing around 6 plants for now in that area. It's a grow space (thanks @Prom ) of about 1.2m x 2m width. I think I could probably sog about +10 plants in there maybe needing more light? I have 440w and was thinking of maybe adding a 50-100w cob if I went that route in the future. 

Just BTW Samsung do no make those boards, they only make the diodes. Do not be caught off with the way some retailers word their lights.

 

I reckon 10+ plants in such a space, you would want more light for that area however you could get away with what you have but results wouldn't be the same as if you had more lights obviously.

As for adding a COB, you could but I would personally rather have a quantum board or LED strips over a COB. Better spread and more even coverage when compared against a COB, although it does also depend on the COB but generally speaking a COB wont have the same spread / coverage when compared against QBs or strips.

[Prom]

3 hours ago, PsyCLown said:

I reckon 10+ plants in such a space, you would want more light for that area however you could get away with what you have but results wouldn't be the same as if you had more lights obviously.

As for adding a COB, you could but I would personally rather have a quantum board or LED strips over a COB. Better spread and more even coverage when compared against a COB, although it does also depend on the COB but generally speaking a COB wont have the same spread / coverage when compared against QBs or strips.

very much agree on the COB... if you add 1 more of the LEDs you have, you run 660watts over 1.2x2.. is enough. But you can also nicely adapt to different canape hights. Stick to 1.2x1.2 for now and add the next light when it fits the wallet. 1.2x1.2 is a rather big grow space. If you do a good run and use the light correct, 2 grams per watt, should be easy reachable. With 440 watts, you should reach over 800g dry. 

How many plants is relative and depends on the strain and what type. If you do a proper 17 cut mainlining, 4 photo plants will need the space. Or 9 tall growing autos or 16 small growing autos. The better you know the strain, the better you know what is coming size wise.

Stick to what you have and can handle.. a full space brings other challanges. After 2 grows, you know very well what makes sense to add to your setup. The lights you have are in my preferred config spectrum wise. I think you will enjoy your grow time. Just watch those temperatures! 

Edited December 3, 2020 by Prom
added last bit