Please help: Switched to LEDs, slow growth, no budding!

[Ritualis]

Hi guys,
I’m quite desperate right now so let me skip to the point (at the bottom you’ll find tl;dr)
Setup and performance until now

• Seasoned indoor grower (~ 6 years)
• Setup: 8x4 (240x120 cm) grow tent
• Lighting: 2x 600w HID (Lumatek, Adjust-a-Wings reflectors)
• Method: SCROG
• Strain: Dinafems’ Moby Dick (8 plants)
• Medium: Soil (Plagron) in classic ~10 gal (40L) pots
• Feeding/nutrients: Canna Terra (Vega, Flores, Rhizotonic, Cannazym, PK13/14)
• Grow cycle: From clones to 75% filled screen 18h MH cycle for about 3 weeks and 2 months of 12h flowering.
• Performance: 1 – 1,25 g/W

I wanted to expand operation and due to HID electricity/output ratio turned to LEDs. As preassembled LED systems are very expensive, I did my fair share of research and at the end decided to do it myself.
This is my new setup

• Setup: 8x4 (240x120 cm) and 6,6x4 (200x120 cm) screen (w/o growbox)
• Lighting: 2 x MeanWell HLG-480H-48A each driving 8 x Samsung HinFlux L09 SL-B8V4N90LAWW 3000K Lm301b diode LED strips + 2 x MeanWell HLG-320H-48A each driving 5 x same LED strips. Strips are mounted on ALU profiles (heatsinks) warming up to 58 – 60 C.
• Method: SCROG
• Strain: Dinafems’ Moby Dick (8 + 4 plants). 4 plants are under additional 6,6x4 (200x120 cm) screen.
• Medium: Soil (Plagron) in ~13,2 gal (50L) AIR pots.
• Feeding/nutrients: Canna Terra (Vega, Flores, Rhizotonic, Cannazym, PK13/14)
• Grow cycle: From clones to 75% filled screen 18h MH cycle for about 1,5 month and almost 3 weeks into flowering I got first signs of buds.
• Performance: /

So, main three changes are the lighting, removal of grow tent and pots. There were previous attempts to expend operation by setup additional screen and putting lights on light movers, but that setup just didn’t give enough light and performance was poor (even less than in tent, about 0,8 g/W). Everything else was the same.

What is the problem now? Veg took twice the time it took under HIDs, but OK, these LEDs are 3000K so I was expecting slower growth. However, the main problem is that even 3 weeks into flowering I don’t see any real budding. With HIDs it usually took just a couple of days for first pistils to appear, now 3 weeks into flowering only few can be seen... Otherwise, plants are looking very healthy, no visible problems etc.

I attached few pics for better understanding.


Can someone please explain what am I missing, doing wrong, should be doing differently and most importantly should I keep my optimism or expect failure?

tl;rd: Switched from HID to LEDs, rate of growth and flowering are very slow and in general just underperforming.

 

[SmokingWings]

Maybe it is the way I look at things but it looks like you do not have enough light per square foot Are the LED units close enough to each other? To me it looks like they are to far apart.

If it was me I would have each bank of 2 LED strips about 6 inches apart (or, 12 to 15 cm apart). Especially in the flower stage.

This could be tested by running another one or two strips over part of one of the scrogs. If those plants start to show more growth than the other plants which are not getting the added light then we would have part of the answer.
///

 

[Old Salt]

You have 58 sq ft or 5.28 m^2 of canopy with potentially 1160W of lighting. That's 20 W / sq ft or 220 W / m^2. Running at maximum power, you have 2/3 the minimum recommended light of 30 W / sq ft. This is going by the datasheet specifying 1000 mA at 44.6V for each light strip.

This would account for the slower growth. I'd double the light strips, on dimmable drivers so that you can adjust the intensity.

 

[Ritualis]

You have 58 sq ft or 5.28 m^2 of canopy with potentially 1160W of lighting. That's 20 W / sq ft or 220 W / m^2. Running at maximum power, you have 2/3 the minimum recommended light of 30 W / sq ft. This is going by the datasheet specifying 1000 mA at 44.6V for each light strip.

This would account for the slower growth. I'd double the light strips, on dimmable drivers so that you can adjust the intensity.

Thanks. Before I had 1200w HPS over 8x4 screen and by all calculations and recommendations 960w of more efficient LED lights should be the same or even better.

 

[Ritualis]

Maybe it is the way I look at things but it looks like you do not have enough light per square foot Are the LED units close enough to each other? To me it looks like they are to far apart.

If it was me I would have each bank of 2 LED strips about 6 inches apart (or, 12 to 15 cm apart). Especially in the flower stage.

This could be tested by running another one or two strips over part of one of the scrogs. If those plants start to show more growth than the other plants which are not getting the added light then we would have part of the answer.
///

Thanks. Pls. see my reply to Old Salt

 

[Old Salt]

Have a look around this forum for the DIY lighting put together by our members...

I built an eight COB 500W dimmable light for a 2' X 4' space. I'll start using it for my next grow, so I don't know how much of that I can actually use.

@PurpleGunRack has two threads you may be interested in:

• Build Your Own LED Grow Light
• DIY Test Build with Samsung Q-series strips

GrowMau5's YouTube channel is also worth a visit.

 

[TorturedSoul]

20 W / sq ft

Yikes. That seems like it'd be significantly too low even if one is growing autoflowering cannabis plants (and, therefore, can be expected to maintain a higher DLI by flowering at 18 or more hours per day instead of 12).

Running at maximum power, you have 2/3 the minimum recommended light of 30 W / sq ft. This is going by the datasheet specifying 1000 mA at 44.6V for each light strip.

This would account for the slower growth. I'd double the light strips, on dimmable drivers so that you can adjust the intensity.

If I was "expanding my operation," I wouldn't be looking at minimums as anything other than numbers that I was heading past (and at full speed). If you do not have enough light for your grow space, either add more light or shrink your grow space... or suffer, along with your plants, I suppose.

If I was doing so and was concerned about electricity use, and heat production... Well, I continue to be intrigued by LED technology - but it's not magic . "Wattage sweet-spots," if we're being honest, aren't that different, regardless of the technology (IMHO). Heat production... I'd expect it to be somewhere around 3.412141633 (err.. approximately ) BTU per watt used, again regardless of the technology. With a good air-cooled HID setup, fan to pull air (from somewhere other than the grow space) through the HID reflector(s), attention to possible leaks in the ducting and the fixtures, and a separate ventilation setup to pull air through the grow space, itself, and (if applicable) through a carbon filter... Insulated covers on the (those) HID reflector(s), if available... Ballast(s) moved out of the grow space...

Well, I might find myself expecting there to be less of a worry about heat in the grow space with the above setup than with some kind of LED one where all power supplies were in the grow space, where the design of the lighting meant that 100% of the heat that the (LED) lighting was producing was getting dumped straight into the grow space instead of the vast majority of the heat the lights were producing being segregated from the general grow space at all times.

With a setup like yours... Hmm. Remove the power supplies from the grow space. The actual lighting part of those lights? Box the heatsinks in and used forced-air cooling; in other words, run ducting - again, from somewhere other than the actual grow space (or its immediate vicinity), to those boxed-in heatsinks, and directly back out of the grow space (and out of its immediate vicinity) with a fan to move air through the run. (Also) again, wholly separate from your general grow space's ventilation run.

BtW, I agree with your assessment, Old Salt.

Aside from that: Don't get me wrong, people often do have heat-related issues. However, sometimes, it's really an issue of not understanding the relationship between light-energy (or more correctly, how much the plants can effectively utilize under different environmental conditions), temperature, and CO₂ levels. Heat tolerance is going to vary somewhat from strain to strain, of course. But in general, if it's 86°F (30°C) or less and my plants appear to be suffering, I'll assume that I'm not giving them enough light-energy for the temperature. If it's above that temperature and my plants appear to be suffering, I'll assume it's either lack of sufficient light-energy for the temperature and CO₂ level or insufficient CO₂ level for the temperature and amount of light-energy they're receiving.

Of course that's just a general rule (to which, like all general rules, one will occasionally find exceptions), and it does assume that everything else is fine - sufficient moisture available to the plant's roots, along with enough airflow through the canopy for proper transpiration (plants self-cool via this mechanism), and great oxygenation at the root zone. <SHRUGS> If something like one of those things happens to be screwed up, well, it'd be like rebuilding the engine on your car when it has a ballooned torque converter, lol, you're still not going to be going anywhere.

I ramble. . . .

 

[SmokingWings]

Something that occurred to me after I left for work is that I have my LED strips closer to the tops of the plants. At least it appears that way to me.

Whether it is right or wrong, I have my lights between 12 and 15 inches from the tops. If the plant grows to close I will adjust the distance by lowering the plants. The lights cannot be adjusted up or down but the pots the plants are in are on blocks so it is easy to just remove a block every time I need to adjust.

BTW, I have let a plant or two grow right up to the LED tube just to see what happens. Also have let a flowering plant grow up and touch the light and then left it so the buds there for several weeks just to see what happens.

 

[Chris Scorpio]

I'd have to agree it looks like your a bit lite on yer lights

I'd do as mentioned and put them closer together

I use nothing but QBs and I personally think they out performed my HPS light

I have fantastic penetration with mine, but I'd say yours is a bit spars campared to mine

 

[Mars Hydro]

Maybe also look at the cost efficient Mars SP 250. The PPE performs very nice as 2.35~2.45umol/j just as the expensive units over thousand USD in the market.

5 Mars Hydro sp 250 ..jpg

• Mars Hydro
• Apr 23, 2019

5 Mars Hydro sp 250.jpg

• Mars Hydro
• Apr 23, 2019

 

[Sinbad91]

Just also bare in mind that your lights have a 120Deg spread. You should be able to get away with placing them as close as 40cm to your canopy top if your light distribution allows for it. A decent amount of your light is being wasted in the walkways/non-canopy areas.

 

[TorturedSoul]

Maybe also look at the cost efficient Mars SP 250. The PPE performs very nice as 2.35~2.45umol/j just as the expensive units over thousand USD in the market.

5 Mars Hydro sp 250 ..jpg

• Mars Hydro
• Apr 23, 2019

5 Mars Hydro sp 250.jpg

• Mars Hydro
• Apr 23, 2019

I recommend a coat of primer, a skim-coat of drywall mud, another coat of primer, and two coats of the brightest white paint the gardener can find. Or a roll of Orca film (not the most inexpensive product in the world, but it's supposed to be very good at reflecting light). Might as well use all the output from those SP 250s that he/she can.

 

[Ritualis]

Yikes. That seems like it'd be significantly too low even if one is growing autoflowering cannabis plants (and, therefore, can be expected to maintain a higher DLI by flowering at 18 or more hours per day instead of 12).



If I was "expanding my operation," I wouldn't be looking at minimums as anything other than numbers that I was heading past (and at full speed). If you do not have enough light for your grow space, either add more light or shrink your grow space... or suffer, along with your plants, I suppose.

If I was doing so and was concerned about electricity use, and heat production... Well, I continue to be intrigued by LED technology - but it's not magic . "Wattage sweet-spots," if we're being honest, aren't that different, regardless of the technology (IMHO). Heat production... I'd expect it to be somewhere around 3.412141633 (err.. approximately ) BTU per watt used, again regardless of the technology. With a good air-cooled HID setup, fan to pull air (from somewhere other than the grow space) through the HID reflector(s), attention to possible leaks in the ducting and the fixtures, and a separate ventilation setup to pull air through the grow space, itself, and (if applicable) through a carbon filter... Insulated covers on the (those) HID reflector(s), if available... Ballast(s) moved out of the grow space...

Well, I might find myself expecting there to be less of a worry about heat in the grow space with the above setup than with some kind of LED one where all power supplies were in the grow space, where the design of the lighting meant that 100% of the heat that the (LED) lighting was producing was getting dumped straight into the grow space instead of the vast majority of the heat the lights were producing being segregated from the general grow space at all times.

With a setup like yours... Hmm. Remove the power supplies from the grow space. The actual lighting part of those lights? Box the heatsinks in and used forced-air cooling; in other words, run ducting - again, from somewhere other than the actual grow space (or its immediate vicinity), to those boxed-in heatsinks, and directly back out of the grow space (and out of its immediate vicinity) with a fan to move air through the run. (Also) again, wholly separate from your general grow space's ventilation run.

BtW, I agree with your assessment, Old Salt.

Aside from that: Don't get me wrong, people often do have heat-related issues. However, sometimes, it's really an issue of not understanding the relationship between light-energy (or more correctly, how much the plants can effectively utilize under different environmental conditions), temperature, and CO₂ levels. Heat tolerance is going to vary somewhat from strain to strain, of course. But in general, if it's 86°F (30°C) or less and my plants appear to be suffering, I'll assume that I'm not giving them enough light-energy for the temperature. If it's above that temperature and my plants appear to be suffering, I'll assume it's either lack of sufficient light-energy for the temperature and CO₂ level or insufficient CO₂ level for the temperature and amount of light-energy they're receiving.

Of course that's just a general rule (to which, like all general rules, one will occasionally find exceptions), and it does assume that everything else is fine - sufficient moisture available to the plant's roots, along with enough airflow through the canopy for proper transpiration (plants self-cool via this mechanism), and great oxygenation at the root zone. <SHRUGS> If something like one of those things happens to be screwed up, well, it'd be like rebuilding the engine on your car when it has a ballooned torque converter, lol, you're still not going to be going anywhere.

I ramble. . . .

Hi,

OP here. Don't know if anyone will see this, but it was temperature all along! Fixed that and had a pretty good round. The following (summer) round now was exceptional to say the least! Thanks again, wish you all good growths.