No idea what's going on here

[JollyShaman]

Hey y'all, first post on ICMag! I've grown in the past, but it's been a while and I really upgraded my system this time. I've never seen this before so I thought I'd reach out for some advice. My leaves are looking limey-yellow with redish-purple tips and spotting.

I'm growing a 2' x 2' x 4' tent with a 200W LED, vented with a thermostat/humidistat controller. I'm trying out Barney's Farm Wedding Cake and Purple Ayahuasca, and got the seedsman White Widow and Bruce Banger as freebies so I popped one of each. First time growing all of these so I'm learning what they like.

Doing it in 1 gallon fabric pots with a soil mix made of compost, coco coir, vermiculite and perlite. My soil mix was a little hot so we fought some nitrogen toxicity in the early stages (I think), the Wedding Cake was the most effected and was majorly stunted. I'm going to mix it down with some peat moss for the next round.

To keep the girls short I tried some manifold training (1st time) and did a little defoliation to let the light through to the lower bud sites. The plants are about 13" tall and 19" from the lights.

Room conditions are like this:
Daytime Temps - 78 F - 82 F
Nighttime Temps - 64 F - 68 F
Daytime Humidity - 46% - 55%
Nighttime Temps - 54% - 60%
Light Schedule - 12/12

Watering every 2 days
Feeding 1/4 cup of the following solution each watering:
1 Gallon Batch:
12 mL BioCanna Bio Flores
10 mL BioCanna BioBoost
5 mL Natural Cal-Mag
2 mL BioCanna BioRhizotonic
pH'd to 6.5 - 6.8

We're about 28 days into flowering now and I'm seeing some purpling on the leaves of all but the Wedding Cake. I think it's some kind of deficiency, but I'm not sure if it's from too little nutrients, lockout, or what? I've increased the feeding to 1/2 cup last week, then 3/4 yesterday after no changes.

The plants don't look too stressed, but I'm worried that's gonna change soon. We only have 4 or 5 weeks to go so I can't be losing leaves this late in the game.

Some pics are under the LEDs, I took some more outside the lights for better accuracy. The red/purple doesn't show up nearly as well in the photos as it does IRL, should I be worried?

The girls under LEDS:
LED

Wedding Cake:
View attachment W0CxaTVF-pDVPg45RwHPL0bqRc80iDWIFIK-8Z0Hlj6ih_GDsBHGLHKpLnQ-dyc-tPsH2o8hbNXPzFOdNJKIVhc_4WopJ7FoQAC- LED

White Widow:
View attachment lGZBYjmNZl7ne087hWQtfFyQNYUwalGlFkya09dSyZZpPU7gm0IG2Ef6fc8q-pNC5VkRl7TfiWTfyuGrKGvlt8kPibE2Pe0JVCuZ LED
View attachment pT9RSGnoS4ybZmEqTv9iGNquG7JwZuxv5rywMGP6LUbbKCG_AdKrU73uxyMAncLBiK_gN5mzG2CxVrpwsiuKKy5yN1t08mND4IEq LED
View attachment 1gEjYci2ijNKubkZINqnHqSPa3_znsmbCQzXQ7kFgDNGZGrXe57Vt-rMBmidNNDtFFLGFoyEHiIWcrmHie7rRbfnsN1EWyJjGL4d Camera Flash
View attachment 5eTI0TRma4yf5wYseY7-YzKS-3iSW4v4M7sEK7Lk1OZfrxTU2dW2Fcrvj9UIes2G9cotoIVE8OxkYcT8UJgREbW-5hmhnB45CpaM Camera Flash
Bruce Banger:
View attachment cIjyduhmt-pLLFult6odMFSCT4Bvsmrx8Y1Nbgc3rYS6FhT1jXMQ1VLNn7O_NL0476zv7abgGUnpBRdv6iFqXQb7hM5Osbe1I_iG LED
View attachment 4golkjqRo1Duq1t_rucBXsAnLkpQuyfroKJmPeIIgS45OBf_q5JSoD6M1TP7c275VoCaqaT_Ufi5ARTpdMzoK7YpEnBHtwvtYf3s Camera Flash
Purple Ayahuasca:
View attachment vAtX8yoRAHZtdTrZjzwflad8xrVF9rxuLfJUo1q32fz-sWXL5n2xarYii92NDnG9GCDO2uyk1mlOsT6aRmMRqJVYQLsPHumiPMZ7 LED
View attachment JoHmXIxMoP4C6ou6xaHqA2qNC472WdAgwUuzj5oQbOktGCOFL2fd7X8Ou-wI0gos8RaX6fjiYSfOLx-bWp9q1f3lW9fdcbQT9RfZ Camera Flash

 

[DaveBowman]

I've had this exact pale yellow-green leaves with the red/purple tips that got progressively worse the further along in flower. Not sure it's applicable here, because you mention your specific pH and it's in range - but for me, the root cause was high pH causing nute lockout. Combined with being too close to my LEDs (it was my first grow not using HPS lights), my plants looked like this but much worse by the end.

I still harvested some really good northern lights nugs that were super frosty, but I know my yield suffered.

I never realized the LED's can burn plants even if it doesn't feel hot to the touch and now am more cautious with my LED grows. Usually I would know if my lights were high enough with HPS just by feeling with my hand at canopy height.

Like I said, not sure if any of this applies to you, but I saw the pics and wanted to share my experience as I have definitely seen this before.

 

[xst89soi7d]

Is it warm in there? Do you have the central heating on? This happens when compost gets too warm. The warm (or maybe hot to plants) compost poisons the plants with warm/hot water and bacteria; leaves go yellow, and regretably they will eventually become so damaged until up to the entire plants leaves drop off. The compost may add additional heat through anaerobic-digestion; so if the compost is warm, this may be activating the microbes even more. In nature composting is a self-fuelling process of heat build up, which eventually result in fires; and which are often reported by composting or compost-recycling-centres. Go here: https://www.bbc.co.uk/news/uk-england-berkshire-23052634 Problems with heat and/or bacteria may be a particular trait of pure-compost; as opposed to pure-peat substrate, which does not contain composting matter, and is therefore a superior substrate. Seed and cutting peat, which contains 80% peat, and 20% compost, may cause much less or no composting (but I can't vouch for it). Westland seed trays compost contains 80% peat. https://www.diy.com/departments/west...7859151_BQ.prd The advantage of 'seed & cutting peat' against pure peat is the packaging size. 'Seed & cutting peat' packaging is much smaller than huge bales of pure peat, which are normally kept outside at garden centres, and as the peat gets soaked with rain-water, the bales literally weigh a ton.

New growth will appear in a few weeks. Even new leaves from flowering-buds are enough for the plant to easily survive on. Buds and sugar leaves seem to be harder to destroy with things like substrate-heat and bacteria. It will just be a case of two to three weeks setback. Hope this helped.

 

[Creeperpark]

Looks like you are using tap water and the pH is swinging up locking out trace elements.

 

[kushedy]

Double the calmag dose

 

[JollyShaman]

I've had this exact pale yellow-green leaves with the red/purple tips that got progressively worse the further along in flower. Not sure it's applicable here, because you mention your specific pH and it's in range - but for me, the root cause was high pH causing nute lockout. Combined with being too close to my LEDs (it was my first grow not using HPS lights), my plants looked like this but much worse by the end.

I still harvested some really good northern lights nugs that were super frosty, but I know my yield suffered.

I never realized the LED's can burn plants even if it doesn't feel hot to the touch and now am more cautious with my LED grows. Usually I would know if my lights were high enough with HPS just by feeling with my hand at canopy height.

Like I said, not sure if any of this applies to you, but I saw the pics and wanted to share my experience as I have definitely seen this before.

That sounds exactly like what I have going on, it's my first time with LED's too and I definitely was a little too close about a week ago. I can't believe you have to hang those things so far away now compared to when LED first hit the market. I remember seeing pictures of people running their lights almost touching the plants when they were new.

Thanks for all the advice guys! I gave the ladies 2 cups of nute solution yesterday to try and get more available for the roots. That should give them a little more Cal-Mag also. They're looking a little more on the green than yellow side this morning so hopefully I'm on the right track. I'll be off to the store for some ph down and a new meter, then test some runoff to get an idea of the ph of the root ball. I'll keep y'all posted.

 

[JollyShaman]

Alright alright alright, my old pH meter has been sent to it's grave ⚰!

I grabbed some collection trays and some stands to keep the pots out of the runoff, then made a solution at 5.8 pH and watered the plants until I collected some runoff in the trays. 6.9 - 7.2 was the range of the runoff so my root balls are definitely on the high side. Now I'm debating if I should hardcore flush them with pH'd water tonight, or if I should just water with low pH (like 5.5) solution until I see the runoff coming out closer to 6?

I'm leaning towards a hardcore flush, but I'm a little worried it'll stress them out even more.

Thanks for the help, y'all saved these girls!

 

[TanzanianMagic]

Hey y'all, first post on ICMag! I've grown in the past, but it's been a while and I really upgraded my system this time. I've never seen this before so I thought I'd reach out for some advice. My leaves are looking limey-yellow with redish-purple tips and spotting.

I'm growing a 2' x 2' x 4' tent with a 200W LED, vented with a thermostat/humidistat controller. I'm trying out Barney's Farm Wedding Cake and Purple Ayahuasca, and got the seedsman White Widow and Bruce Banger as freebies so I popped one of each. First time growing all of these so I'm learning what they like.

Doing it in 1 gallon fabric pots with a soil mix made of compost, coco coir, vermiculite and perlite. My soil mix was a little hot so we fought some nitrogen toxicity in the early stages (I think), the Wedding Cake was the most effected and was majorly stunted. I'm going to mix it down with some peat moss for the next round.

To keep the girls short I tried some manifold training (1st time) and did a little defoliation to let the light through to the lower bud sites. The plants are about 13" tall and 19" from the lights.

Room conditions are like this:
Daytime Temps - 78 F - 82 F
Nighttime Temps - 64 F - 68 F
Daytime Humidity - 46% - 55%
Nighttime Temps - 54% - 60%
Light Schedule - 12/12

Watering every 2 days
Feeding 1/4 cup of the following solution each watering:
1 Gallon Batch:
12 mL BioCanna Bio Flores
10 mL BioCanna BioBoost
5 mL Natural Cal-Mag
2 mL BioCanna BioRhizotonic
pH'd to 6.5 - 6.8

We're about 28 days into flowering now and I'm seeing some purpling on the leaves of all but the Wedding Cake. I think it's some kind of deficiency, but I'm not sure if it's from too little nutrients, lockout, or what? I've increased the feeding to 1/2 cup last week, then 3/4 yesterday after no changes.

The plants don't look too stressed, but I'm worried that's gonna change soon. We only have 4 or 5 weeks to go so I can't be losing leaves this late in the game.

Some pics are under the LEDs, I took some more outside the lights for better accuracy. The red/purple doesn't show up nearly as well in the photos as it does IRL, should I be worried?

I looks like molybenum deficiency/lockout. The pale tops, the red coloration, near the top of the plants (non-mobile nutrient deficiency) indicate a non-mobile nutrient deficiency (calcium, sulphur, silica, trace elements like molybdenum).

https://www.growweedeasy.com/cannabi...num-deficiency

This happens at lower pH ranges. I think the pH is too low for organics, and should be pH'd to 7.0. 7.5 for a couple of waterings to raise the pH.

Also, you should check runoff water to see if there is a buildup of nutrients in the soil. The flowering nutrients also tend to pull down the pH.

UPDATE

I also forgot - molybdenum is also depleted if you use nitrogen nitrate instead of ammonium nitrate in flowering. Molybdenum is used to turn nitrogen into ammonium nitrate.

Molybdenum is an essential component in two enzymes that convert nitrate into nitrite (a toxic form of nitrogen) and then into ammonia before it is used to synthesize amino acids within the plant. (Source: PTHorticulture)

And...

My soil mix was a little hot so we fought some nitrogen toxicity in the early stages

The nitrogen in Canna Bio Flores is not the issue, there is probably some nitrogen in the soil.

Also, molybdenum is synergistic with nitrogen and copper.

 

[JollyShaman]

I looks like molybenum deficiency/lockout. The pale tops, the red coloration, near the top of the plants (non-mobile nutrient deficiency) indicate a non-mobile nutrient deficiency (calcium, sulphur, silica, trace elements like molybdenum).

https://www.growweedeasy.com/cannabi...num-deficiency

This happens at lower pH ranges. I think the pH is too low for organics, and should be pH'd to 7.0. 7.5 for a couple of waterings to raise the pH.

Also, you should check runoff water to see if there is a buildup of nutrients in the soil. The flowering nutrients also tend to pull down the pH.

UPDATE

I also forgot - molybdenum is also depleted if you use nitrogen nitrate instead of ammonium nitrate in flowering. Molybdenum is used to turn nitrogen into ammonium nitrate.



And...



The nitrogen in Canna Bio Flores is not the issue, there is probably some nitrogen in the soil.

Also, molybdenum is synergistic with nitrogen and copper.

Serious thanks for the links here!! Those pictures on grow weed easy look exactly like what I'm seeing in the tent. If the pH of what I'm feeding and watering is at 5.8 and the runoff is testing at 7.5 I'm thinking my soil pH must be too high. I'm worried I'm sitting up at 7.5 - 8.0 or somewhere like that. I had used a cheap meter for the first part of this grow and after replacing it with a Hanna 98107 I realized my old meter was reading about 1.5 pH lower than it should. I'm thinking all of my feeding and watering up until Wednesday was probably around a pH of 7.3 - 8.3 instead of 5.8 - 6.8 like I was shooting for.

 

[Hammerhead]

PH is the #1 issue when having plant problems. Anytime you start seeing issues check your runoff PH/EC it will tell you where to start. It should never be a drastic difference from what you feed. The proper PH depends on what medium you're using. If your medium looks like COCO the proper PH 5.5 to 6.3. Use 5.8 as your base PH. If your medium looks like soilless the proper ph range is 6.3-6.8. Use 6.5 as your base PH. Always read the bag to see if they use PH buffers. Ph buffer will keep your medium at 7. This can skew your runoff PH readings. If the PH is off the plants cant uptake what they need.

 

[GoatCheese]

I think that’s caused by the LED being too close to the plants/ you’re running it too hot. Modern leds are very intense and need much more clearance to the canopy than old purple led lights.

My plants looked more or less the same or even worse during my first cob run before I realized what’s going on and how powerful white cobs/leds are.
I have three Cree cobs about 65cm above the canopy and 90 watts (30 watts each) is about the max I can run them esp. when the air is dry already because of northern winter.

Modern leds/cobs will dehydrate the leaves if they’re too close to the plants, esp. when plants are growing in soil and the soil dries out too much. Coco/hydro is much more forgiving under leds cause there is more moisture in the plants’ system than in soil grown plants. Modern leds are very different animals compared to hps/mh lights, imo..

So dim the light down abit if you can’t raise it any higher.

You might wanna start checking the soil moisture every day cause 1 gallon pots dry out fairly fast, so you may have to start watering them more often. Some plants drink more than others so you don’t shouldn’t give all of them a fixed amount of water, but water them according to their needs = some plants you might have to water every day, some might be ok with every other day..

 

[JollyShaman]

I think that’s caused by the LED being too close to the plants/ you’re running it too hot. Modern leds are very intense and need much more clearance to the canopy than old purple led lights.

Thanks for that! I think that's definitely playing a part. I was running the light a little closer than the mfg recommends earlier in the grow. Light burn was my first thought when I noticed the yellowing wasn't responding to increased feeding, so I rearranged my little tent to get the light up to 21" (53 cm) above canopy. That was about 10 days ago. The light mfg says to keep it 18" - 22" above canopy during flowering so I think I'm OK now.

If I'm still having problems once the pH comes into range I'll turn it down and know I need even more distance on the next go.

 

[GoatCheese]

Thanks for that! I think that's definitely playing a part. I was running the light a little closer than the mfg recommends earlier in the grow. Light burn was my first thought when I noticed the yellowing wasn't responding to increased feeding, so I rearranged my little tent to get the light up to 21" (53 cm) above canopy. That was about 10 days ago. The light mfg says to keep it 18" - 22" above canopy during flowering so I think I'm OK now.

If I'm still having problems once the pH comes into range I'll turn it down and know I need even more distance on the next go.

Most led light manufactures seem to know shit about how their lights behave. They just sell them. Most of them state you can keep your white leds much closer to the canopy than you actually can in real life. Grow environment changes play a huge part on how close/hot you can keep your white leds going.

If the leaves feel abit dry and harsh on your fingers then it’s the leds that did it, and to me those leaves look like led damaged. ..my leaves also had purple colors on them and yellowing when I fried my plants during my first cob grow.

Even if you get the light dialed in, the leaves on your plants will look abit pale and feel little dry the rest of the grow, but they should start feeling little softer (more moist) to the touch in few days when you get the light dialed low enough.

On your next grow, if you see your plants losing their waxy, shiney looks and they seem abit pale and dry (matte) looking then your light is running abit too hot. Plants will show some symptoms of this quite fast, even in 10 minutes after you’ve turned your light on too hot.

Keep your light as high in your tent as you can and then use the dimmer to dial it in to suit your needs.

Leds/cobs are great lights once you get to know them, but it takes a while to figure them out when you switch to modern leds from HPS lights. My Cree cobs are much more powerful lights at 85-90 watts than my 250 watt cool tubed HPS was.

Good luck with the rest of the grow. your plants will still yield nicely once you get the situation under control, no worries..

 

[JollyShaman]

Thanks for even more info GoatCheese! I was wondering why the leaves felt so crispy. I turned it down to 90%, maybe I can talk my wife into letting me get a par meter now

 

[GoatCheese]

Thanks for even more info GoatCheese! I was wondering why the leaves felt so crispy. I turned it down to 90%, maybe I can talk my wife into letting me get a par meter now

Trial and error showed me quite quickly how hot i can run my lights, once you understand the symptoms of led damage on leaves. I don’t have any sort of light meter and I’m not gonna buy one, those are fairly expensive, imo.
You can get a watt/energy consumption meter for around 15 dollars/euros if you want to know how the dimmer really works on your light. The dimmer that came with my DIY cob-set isn’t actually fully linear, meaning when it’s should be at half way it actually isn’t at 50% but around 45% according to my watt meter.


Also, if you’re gonna buy some sort of light meter read about white leds and par/ppfd meters first before buying one, because apparently not all meters read the full spectrum of white led light and so the reading isn’t accurate.

….
At 90% ( =180W) of 200 watts it may still be too much power at 50 cm to canopy. You may have to go as low as 60-70% but I’m sure you will figure it out in time.

 

[f-e]

I notice you using 12ml of food and 10ml of boost. The bottles suggest 15ml and 7.5ml respectively. This is pushing the things you need further down in the quantities available.

I think you may run them a bit dry and at a high pH. This might be because you made your own substrate. Which makes it hard to advise you. For instance Mo is showing, which likes to be above 6.5 in soil but below 6.5 in hydro. How much stuff you mixed in with the compost can skew the advice you receive. The range of problems I see look like long term underwatering and high pH. Though I wouldn't be so far from Canna's suggestions with poorly plants either.

50w a foot is a lot if it's a good light. Ill plants that can't find their food need a rest. You can't run a marathon on a pack of cheesy poofs. Though you might walk it. 50w of light alone isn't going to do that though. I'm doing a 50w per foot run right now and the upper foliage is fine. However my RH is higher to get them stomata open and I have lots of water available at the roots so I can get my calcium carrying things around. However I'm not saying 50w is good. Anything over 40w is troublesome. 30w is fine. 15w keeps goatcheese happy with HID like results he says. If your light can't be turned down you may need to think about shading it a little or find out of it can use an external dimmer. Ultimately it might just be too big for a 2x2

I have twice gone shop organic and each time got similar signs under fairly lit conditions. It just didn't have anything in it. Take that and cut it with drainage aids, then under feed and over illuminate. It's probably what I'm looking at.

 

[GoatCheese]

F-E, bro
What you don’t seem to mention in your square foot-calculations is ”at what distance above canopy”, which is the main problem with modern white leds. You talk about foot print /square foots but don’t mention the usable height above that foot print.

Yes, I can only run my cobs with 90 watts of power for the 50cm x 90cm foot print of my tent, but I can’t raise the light fixture any higher. The tallest plants/tops are now about 55cm away from the closest cob, but if I could raise the light fixture another 20 cm away from the tops, then I could use maybe 15-20 watts more.

In the summer time I could run the cobs little hotter cause there’s more humidity in the air, but now the 90 watts is just about the max for me because of dry winter air here, and because I’m growing in soil. Coco plants seem to do better under my cobs cause there is naturally more water in the plant tissue, cause coco growing is more like hydro. In soil the leaves are noticeably drier no matter how moist I try to keep the soil.

:::
What is my personal experience with my cobs and what I have understood from few other people’s reports is that; you can have more lumens at canopy level when you have the light fixture raised high enough and used with more watts, compared to how much lumens you can have at canopy level when the light fixture is at fairly short distance above canopy and using less watts without the leaves suffering. Do you guys understand what I’m trying to say?

Meaning, once you have enough air molecules between the canopy and the light fixture to eat out some of the energy of the intense light (photons) of cobs/leds ,you can have more lumens at canopy level than you could if you’d keep the leds/cobs closer to the plants and dimmed the light fixture down.
..i have slept too poorly lately for my English skill level to find the right words to explain this any better atm. Hope you guys can understand what I’m trying to say.

:::
Yes even with just 80-90 watts I could grow 6 plants of my big yielding CBD Critical Cure keeper in that tent yielding 40+ dry grams per plant, which would make 2,6+grams/watt ..in soil that is.
Peace

 

[JollyShaman]

Thanks for the input f-e. I don't feel like I've been underwatering; but, I've been thinking of this like growing in soil so I'm letting the top inch get a little dry before watering again. I'll start treating these more like coco and see if they respond better. I definitely have high pH issues, but I don't think it's the substrate mix causing it. My old pH meter was reading -1.5 so everything was being fed and watered at around 7.3 - 8.3 up until about a week ago. I'm feeding and watering at 5.7 now to bring it back down.

I've turned the lights down to 75% yesterday so they should be about 150 watts now, or 37.5 watt/sq. ft. The plants seemed to appreciate it, they look more relaxed this morning.

 

[JollyShaman]

UPDATE, in case you're curious:

The girls are doing a little better now, we had the first orange pistils start showing yesterday so they're starting with ripening now. My runoff pH is still coming out at 7.1 - 7.3 when watering and feeding at 5.8. I'm remembering now that I started with a lazy mans Coots mix with coco coir and added a little vermiculite to give the microbes a place to dig into. When I mixed it I didn't think about the pH at all and figured feeding and watering at proper pH would do the trick.

Lesson learned on that one. I'm going to be getting some minerals from buildasoil.com to get the pH into range:
https://buildasoil.com/products/mineral-mix-for-coco-coir?variant=1204042928

White Widow then and now:

​
Then ^^^

​
Now^^^

Bruce Banger:

​
Then^^^

​
Now^^^

Ayahuasca Purple:

​
Then^^^

Now^^^​​​​​​​

 

[GoatCheese]

Can't see the photos, bro