Stretching seedlings from too much light?

[Terepeneterrapin]

As subject states, and a follow up from advice on my other thread. Could my seedlings be stretching because of light stress rather than a lack of light?

I got a 120w light that I ran at 18ish inches. However I lowered it since I started seeing the stretch at first. Now they’re around 12inches because I read that 24 is usually a recommendation for 240w LEDs. I worry stretchings only getting worse, making me think it was just too strong to begin with

Anyone with experience growing seedlings with LEDs can chime in

 

[Emilya Green]

no, light stress causes physical damage to the leaves, much akin to a sunburn. If your plants are stretching, they are looking for more light

 

[VetSmoke85]

Is the light 120W at the wall?

 

[Terepeneterrapin]

Okay thanks Emilya wanted to nail that down. I’ve Read some conflicting stuff that says too much light can cause stretching and so on but these places are often vague on the exact symptoms.

I’ll keep watching them for now. Appreciated

 

[Terepeneterrapin]

Hi @VetSmoke85 im not good with the terms, nor do I have the tools to check it’s draw at the point. It’s an aliexpress quantum board that used Samsung lm301b diodes. It uses a meanwell driver so the specs say it draws 120w at maximum

 

[VetSmoke85]

Hi @VetSmoke85 im not good with the terms, nor do I have the tools to check it’s draw at the point. It’s an aliexpress quantum board that used Samsung lm301b diodes. It uses a meanwell driver so the specs say it draws 120w at maximum

Ah okay cool. It should be then. You can buy a little meter to plug into the socket and check the power consumption really cheap. Quite handy to have around.

 

[Terepeneterrapin]

Manufacturer claims it’s 120 real draw too (just to add)

 

[Terepeneterrapin]

Yeah I’m SOL for tools haha. I’ll probably be well stocked after the outcome of this grow. I’ll grab the meter next time I’m out.

I did some background work to make sure not to get those ‘knightbrite’ style Mars knockoffs. Reviews tend to say these guys are fairly accurate too.

I’ll watch the seedlings and post a pic if anyone’s following tommorow onward.

 

[Emilya Green]

Okay thanks Emilya wanted to nail that down. I’ve Read some conflicting stuff that says too much light can cause stretching and so on but these places are often vague on the exact symptoms.

I’ll keep watching them for now. Appreciated

Any place putting out nonsense like that needs to be shunned... it is exactly the opposite of what actually happens. Prove it to yourself... put one seedling under a good bright light at the proper distance and put another one in a windowsill to get the indirect sunlight. Trust nothing you read online if you can't test it yourself.

 

[skirk]

I'm surprised you have stretching with a 120w at 18." I use a 24w Tao Tronic at 12" for the first week from sprout with no stretch at all. How many days from sprout and how long is the stem? Any pics?

 

[Terepeneterrapin]

@skirk Yeah skirk had me thinking. Some say even a 40w CFL is enough to help your seedlings. I think i nailed the true culprit. Believe my plants were actually having heat stress not light related issues. Long story short after testing several heights with my new fans for cooling the stretching seems to have stopped entirely. My tent was reaching somewhere close to 30 degrees C sometimes cause of my lights.

Im Getting another fan to keep temps down and gonna keep observing. This is a pic of the stem last night. After what you said about your Tao light i think i'm convinced its the darn heat stress. However there was an issue where my LED power jack snapped and i had to repair it, so i had to leave the seedlings without lights for 12 hours. So far the two plants germed about 2-3 Days ago so still very young.

 

[Terepeneterrapin]

@Emilya Think thats a good chunk of wisdom to live by in the growing world haha. Well if anything comes close to a test like that, I've been alternative height lengths and checking the growth of the plant.

However as i replied to @Stunger earlier im starting to think its the heat stress thats affecting my plants. Cause of my lights and a lack of a fan (till yesterday), i was having ranging temps from 27-29. I really feel this affected the stretch cause honestly, i didnt make sense why my lights would struggle that much to keep em alive. There was also the issue of the 12 hour dark period cause of my broken LED. What do you think?

 

[BeanTownFan420]

I prevent stretch weak stems and plants that cannot take the light because I germinate under 400watts MH and keep it 12 to 14 inches away till flower then I back up as I add more light. If I can do it so can you.

Geminating under MH

• BeanTownFan420
• Oct 21, 2020

Seedlings

• BeanTownFan420
• Oct 26, 2020

Healthy seedlings

• BeanTownFan420
• Oct 30, 2020

Seedlings

• BeanTownFan420
• Nov 14, 2020

Day 3 of the flip super healthy they should yield one nice cola each.

• BeanTownFan420
• Nov 17, 2020

400 watt MH

• BeanTownFan420
• Nov 20, 2020

Lamp is only 12 inches from my canopy pushing it to the max for large leaf growth with wide fingers.

• BeanTownFan420
• Nov 20, 2020

Day 18 and 10 of the flip

• BeanTownFan420
• Dec 2, 2020

 

[Terepeneterrapin]

Just some input for this discussion. Heres a pic of the plants about 8 hours since the initial notice of the stretching. Be weary of the angled down shot (makes it look a tiny bit 'big'), but essentially the stretch seems to halted and the leaves are spreading out. This is after I implemented a fan between the lights/tops and INCREASED the distance of light to my plants (12 inches to 18).

 

[Terepeneterrapin]

@BeanTownFan420 Wow never thought id look at short seedlings and be jealous haha. Those look great and i guess youre saying your MH was giving too much light, so you brought the distance up?

I got a 120w light and originally i ran it at 12inches. Ive just increased the distance but also, there has been issues with my temp ranging between 27-29. I posted about it just now in the thread. You think the heat stress could also be why my seedlings are stretching

 

[BeanTownFan420]

If you have more soil fill that bag right up to support the stem as you water soil will still get compaction and lower.

 

[BeanTownFan420]

No I only brought the lights back because I added more lamps.

Day 11 and day 3

• BeanTownFan420
• Nov 25, 2020

 

[Terepeneterrapin]

@BeanTownFan420 Yeah bean a few members mentioned a similar thing. Im just bout to go pick up some potting soil (ran out) and mix it in with some perlite. Gonna get to it asap. F.Y.I These two are autos as well

 

[Terepeneterrapin]

@BeanTownFan420 Do you think it could be heat stress? My temps were ranging 27-29 degrees C. Also should i make the top soil mix a little looser to improve the compaction?

 

[BeanTownFan420]

No they are stretching from lack of intense light the best way I can explain light is sun comparison since plants germinate in open fields in direct sun and survive I doubt you can give a seedling to much sun so how could you possibly give it to much lower powered bulb light.