Living Soil LED Grow - Deficiencies? Light Stress?

Greetings all. Been running two sealed rooms since January now. Each room has a 4x8 bed of living soil. Above each bed are 2 Progrowtech EV700 spectrally tunable fixtures. I have a 12k mini-split in each room, dehumidifier on a titan Saturn 6 controller, and Co2 supplementation on a Saturn 6 controller.

This is the soil mix I used:
1 part castings, 1 part pumice, 1 part peat
Also about 5% of the mix was biochar inoculated with fish hydrolysate

Minerals per cu ft:
2 cups cascade minerals (basalt)
1 cup oyster shell flour
1 cup Gypsum

Amended per cu ft:
1 cup kelp
1 cup MBP
1/2 cup crustacean meal
1/2 cup Karanja/neem blend

NO DOLOMITE LIME WAS ADDED.

I am only using water. Have not amended with anything other than the decomposing mulch layer and dead clover from canopy shade.

I am having great results with this soil blend outside. Great results with this soil blend indoors under T5 in my veg room. As soon as plants are established in my 4x8 beds, and the spectrums on the LED’s are being increased, I start to see issues show up. Issues start to appear when the plants go under the 4200K CMH in my veg room as well, but they don’t really ever get as bad as they do under the LED’s The issues seem to be isolated to the upper growth the most, with shaded lower growth showing healthier. Stems are also showing purple streaking on certain strains.

I’ve attached some photos. Two of them are from a room running Stardawg currently in flower, and it’s the first cycle in that bed to get out of veg. The other two photos are from a room currently in veg running Dank Zappa, showing a different issue with yellowing leaves. This bed has had two full cycles (albeit not great cycles). The only way to keep the damage at bay is the keep the fixtures further from the plants, which is not the way the fixtures were designed to be used. In veg, this is fine. But in flower, I can’t help but feel that it’s contributing to smaller bud size at this stage (week 5).

I know plenty of people running these fixtures less than a foot from the top of their canopy in a hydro/feed based environment with great results, but I’m not willing to go to hydro. I built my grow around my soil, not the light fixtures. I have the opportunity to sell them back to the manufacturer, albeit at a 20% restocking fee, because nobody over there has been able to help me figure out what my issue is. The manufacturer of the fixture doesn’t seem to have any support or experience to draw on for people cultivating in soil without salt based fertilizers/feeds.

Any help is greatly appreciated as I’m starting to lose interest in this hobby.

What is MBP? I'm no expert, but it looks like it might have too much nitrogen, and maybe it's lacking magnesium. But I'm just beginning to diagnose deficiencies, so maybe wait for the experts.

PadawanWarrior said:

What is MBP? I'm no expert, but it looks like it might have too much nitrogen, and maybe it's lacking magnesium. But I'm just beginning to diagnose deficiencies, so maybe wait for the experts.

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Malted Barley Powder

jHands said:

Malted Barley Powder

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Thanks, that makes a lot of sense. I should of thought of that since I use it too.

I’ve had stacked well cooked soil with my own amended VC and had issues. What water do you use? PH it to 6 - 6.8 with some type of organic only ph down and I’ll bet your issues go away.

Gingeroot said:

I’ve had stacked well cooked soil with my own amended VC and had issues. What water do you use? PH it to 6 - 6.8 with some type of organic only ph down and I’ll bet your issues go away.

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I’m running blumats. Kinda hard to pH with them. Plus, I’m following the method of not having to pH living soil. I don’t think it’s a pH issue. My plants that are outdoor in the same soil mix are absolutely crushing it. It’s gotta be an environmental thing and/or something to do with the lights and the demand they put on the root system for nutrients.

jHands said:

I’m running blumats. Kinda hard to pH with them. Plus, I’m following the method of not having to pH living soil. I don’t think it’s a pH issue. My plants that are outdoor in the same soil mix are absolutely crushing it. It’s gotta be an environmental thing and/or something to do with the lights and the demand they put on the root system for nutrients.

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Nothings more demanding than the sun! What water do the outdooors get? I stopped listening to not PHing living soil and haven’t had one issue since. Could be your waters PPMs are too high indoors?? Just a suggestion.

Gingeroot said:

Nothings more demanding than the sun! What water do the outdooors get? I stopped listening to not PHing living soil and haven’t had one issue since. Could be your waters PPMs are too high indoors?? Just a suggestion.

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So are you saying that you now check the PH of your soil?

The plants get the same water, inside and out. Also, to be noted, is that I have a different strain growing outside. It’s gotta be something with the indoor environment and/or LED lights. All logic points to the plants not responding well to the fixtures. Leaf damage is concentrated to upper leaves, disappears deeper into canopy. Etc.

Sorry I missed the point about the tops only so yeah could be heat or light stress for sure.

I have checked soil PH in the past but found out my water was too alkaline even with living soil! That water also had a higher PH. I’ve also done clone comparisons several times and my plants always grow noticeably better with PH’d water around 6.5ish.

Well based on what I’ve shared, would you agree it’s likely not a pH issue? My plants outside are absolutely crushing. My plants under T5 grow vigorous and healthy. As soon as they are introduced to the environment with LED’s, they start to have issues. I’ve been told it’s the 660nm red that is causing the issues. Seems to be common with the fixtures in soil. I’m about to say fuck it and just sell them and throw up 630 CMH or Fluence fixtures in place of them. I want to grow plants, not play mad scientist with tuning spectrums to meet each strains individual needs. Funny thing is, guys I know that grow with salts have no issues using these lights at peak power and never have stress issues at all.

Never heard of those lights.

What height do you have them above your plants?

They are currently around 3 feet above the canopy. I had to move them further away to counteract the stress. They’re supposed to be ran close to the canopy, and the only ones I see doing that are in hydro. Something about soil and LED tech not aligning well.

Yah prob not PH..specially with the others doing good. I use that spectrum in LED too. How hot is your room?

Gingeroot said:

Yah prob not PH..specially with the others doing good. I use that spectrum in LED too. How hot is your room?

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Running 80-83. Perhaps my humidity is off? I’ve also been led to believe recently that I may have too much airflow over my canopy, therefore reducing leaf temperature too much.

Also to be noted, my Co2 levels run higher than ambient in the room because of offgasing from the soil. I don’t believe this is the cause of the issue, just mentioning it.

When Freshwater Farms was still cultivating in Oregon, they had nothing but issues running these fixtures with living soil. I spoke to the head grower (Josh Steensland) recently, and he said it’s the red spectrum. Also recommended just switching to CMH and saying to hell with the LED’s.

Curious as to which fixtures you’re running, ginger?

I’ve used Kessils, Area-51s, and even induction with supplemental 660nm. 315w LEC is still my go to. I was gonna ask about your CO2 levels but that doesn’t sound high at all. I range between 78-85 with all LEDs without an issue and my panels are usually 12-18” above canopy. Your problems a tough one...hope someone can help.

Edit..I always check my temps at leaf surface

Gingeroot said:

I’ve used Kessils, Area-51s, and even induction with supplemental 660nm. 315w LEC is still my go to. I was gonna ask about your CO2 levels but that doesn’t sound high at all. I range between 78-85 with all LEDs without an issue and my panels are usually 12-18” above canopy. Your problems a tough one...hope someone can help.

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My Co2 tanks rarely kick on. My rooms are sealed super tight, and are around 7’6” by 11’ with a 4x8 bed of living soil in each. The ambient levels hover around 1100-1200 in the room due to the soil activity. If I’m in the room pruning for an extended period of time, the levels easily exceed 2000 and I have to vent the room while pruning and afterwards.

You say your favorite light to cultivate with is the CMH. I have 2 CMH 315’s on movers in my veg room for vegging plants up to 3 gallon pots before planting in their final bed. Plants seem to like the CMH. I’ve been debating getting rid of the fixtures I have and throwing up CMH over the 4x8. Not sure how many or what size fixtures to get though ‍. How are yields on the CMH fixtures compared to DE gravitas? I need to be able to pull 4 lbs consistently out of a 4x8 bed, as the future business model this small grow is r&d for is based on 2 lbs out of a 4x4 area.

You should be able to pull that with a large bed and at least a 4 week veg with any decent light and genetics! Bigger the root bigger the fruit! Gravitas are nice and peaked my interest but I can’t see myself making the change when I can get 1.5 g/w with CMH. I use the Phillips 3100k in a vertical fixture for 3x3 coverage. I’m opposed to light movers when you can just cover all areas at once.

Still baffles me that 660 could hurt your grow...

Never used gas enrichment with led panels but i would think that with efficient panels at 88w/ft, you could run into problems with "low-ish" leaf temps, fwiw most modern led growers run temps in the 80-84f area without gas enrichment.

*mybad, misread the first post.

Gingeroot said:

You should be able to pull that with a large bed and at least a 4 week veg with any decent light and genetics! Bigger the root bigger the fruit! Gravitas are nice and peaked my interest but I can’t see myself making the change when I can get 1.5 g/w with CMH. I use the Phillips 3100k in a vertical fixture for 3x3 coverage. I’m opposed to light movers when you can just cover all areas at once.

Still baffles me that 660 could hurt your grow...

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Curious - do you follow VPD throughout your grow? I’ve been led to believe recently that being out of the VPD range could be contributing to my issues.

I’m not sure if it’s the 660 that’s hurting me, or the blend of the spectrums being off. Either way, I’m probably moving away from these fixtures. Typically my routine right now is I veg under CMH 4200k in 3 gallons until I have plants that are about 2.5 feet tall with 4-6 tops. I then transplant into the bed, usually 12 plants in a 4x8. I add a layer of trellis instantly and position the branches in a manner that the tops are spread out. I’m thinking I can get away with a 1-2 week veg if I continue this with CMH. I’ve also heard of people blending CMH with MH/HPS, but that seems like a waste of time to me. Do you think that 2 630’s over a 4x8 will be enough light to hit those numbers? Would 3 be too much? Do you veg with the 3100 bulbs or do you switch in 4200’s?

I haven’t dabbled in the VPN on purpose...sounds like getting your environment right and that depends on your lighting/CO2/air flow etc.

I personally veg with LEDs now but have used it alllll! I like to save the wattage for where it’s really needed. I personally like vertical hoods and will probably never go back to anything horizontal. Just a preference as I seem to lose light. If my plants get outta the 3x3 footprint I supplement with LED. If I had a 4x8 I’d use 4 vertical hoods with 315w and prob kill it. Just gotta keep the temps slightly lower than an LED grow. Hope I helped and now I want to start a journal.

Edit...possible to get 4# with those four fixtures at 1.5 g/w