Kingbrite Magnesium Defficency

[4$gMn20]

Hello everyone, I have been suffering from magnesium deficiencies for several crops since I used a kingbrite 3500k quantum board with samsung lm301h and cree chips.
I have tried to change the type of substrate, change nutrients, add calmag, add epsom, etc. I'm beginning to doubt the spectrum offered by this quantum board.
I currently have the following growing conditions:
-Substrate: Canna proffesional plus coco coir mixed with perlite
-Nutrients: Greengenes jacks 321 formula using high frequency fertigation
-Temperature: 25°C
-Relative humidity: 70%
-Ph: 5.8-6.2
-Strain: Panama x Pck from Ace Seeds
I attach photos of the plant and the nutrients used with hydrobuddy (I think the magnesium provided should be enough). I don't know if anyone else with this type of LEDs is suffering from these deficiencies and I wanted to share it with you. Good vibes

 

[f-e]

The amount of K looks toxic. You are giving 200ppm and the coco is giving 100ppm more. 300ppm in veg is huge. Half that is enough for some cannabis plants in peak flower.

I don't specifically see Mg deficiency, and no other recipe I have seen gets close to the 90ppm of jacks. Other studies have found over 70ppm to have a negative effect. It can lead to less being taken up. Coupled with the high K, it's leading towards the idea of lockout. K pushes out N and that I see as an even light colour over the plant. Along with other less identifiable issues. I don't know the strain, but see that plump leaf of over feeding.

Reduce your K and don't keep them so wet. Do water to run off, but let them use 70% of the moisture between feeds. Canna coco is a peat like consistancy, not suited to the constant wet feeding regimes of better draining coco's.

Edit: To say better draining isn't right. Higher draining is more accurate. What better is, depends on your needs. Coco isn't a single product. It falls into groups. Canna's standard stuff is a coco peat. Their cogR is very fibrous. You could feed cogR all day long. If you put it in a pot and water it, the water comes straight out. It comes as dry compressed boards. You lay them in gutters and they expand to rockwool slab size. They are just for high frequency dripping. Many guides seem to of lost sight of the fact coco isn't all the same thing. It can be very very different. What you have should be dried back between feedings. Anything from 50-70% of the moisture used. It's peak water retention is very high, and it won't work properly if you keep it at that level.

 

[exploziv]

You are very very high in Mg so Mg def shouldn't be your problem. Your feed regimen doesn't look balanced at all.

 

[4$gMn20]

The amount of K looks toxic. You are giving 200ppm and the coco is giving 100ppm more. 300ppm in veg is huge. Half that is enough for some cannabis plants in peak flower.

I don't specifically see Mg deficiency, and no other recipe I have seen gets close to the 90ppm of jacks. Other studies have found over 70ppm to have a negative effect. It can lead to less being taken up. Coupled with the high K, it's leading towards the idea of lockout. K pushes out N and that I see as an even light colour over the plant. Along with other less identifiable issues. I don't know the strain, but see that plump leaf of over feeding.

Reduce your K and don't keep them so wet. Do water to run off, but let them use 70% of the moisture between feeds. Canna coco is a peat like consistancy, not suited to the constant wet feeding regimes of better draining coco's.

I have been following this jacks hydro formula and from what i see majority of formulas have a target near 200 ppm of K, so I dont know

Thanks for the advice on canna coco, first time I hear it, it can be useful!

 

[GoatCheese]

Yea, like f-e suggested, maybe it’s a watering problem and the coco stays abit too wet. There’s some green algae growth on the perlite which also suggest the substrate has stayed fairly moist alot of time.

It’s very easy to dehydrate leaves with modern leds and usually one of the first signs is that the edges of the leaves start to curl down abit and your leaves aren’t doing that at all, so it could be a little over watering problem rather than the leds making your plants look abit pale.

 

[4$gMn20]

You are very very high in Mg so Mg def shouldn't be your problem. Your feed regimen doesn't look balanced at all.

How many ppm of NPK and (ca mg) would you recommend me for a balanced feed for coco coir? Thx

 

[exploziv]

First of all I think it may be a bit too high EC if you feeding multiple times a day, for this stage and such small plants. Have you ever checked runoff EC?
I would add a bit to the N/Ca for this stage.
I would also feed less P at this stage but I guess you are stuck with that nute..
Then I would almost half the Mg/S.
Depending on runoff EC I would decide what EC to feed..

 

[4$gMn20]

First of all I think it may be a bit too high EC if you feeding multiple times a day, for this stage and such small plants. Have you ever checked runoff EC?
I would add a bit to the N/Ca for this stage.
I would also feed less P at this stage but I guess you are stuck with that nute..
Then I would almost half the Mg/S.
Depending on runoff EC I would decide what EC to feed..

I have been using the feed at 50% strenght for the first 3 weeks and my runoff EC is 0,9.
Im gonna try to increase N and Ca and decrease K and P for the next mix.
Thx!!

 

[4$gMn20]

Yea, like f-e suggested, maybe it’s a watering problem and the coco stays abit too wet. There’s some green algae growth on the perlite which also suggest the substrate has stayed fairly moist alot of time.

It’s very easy to dehydrate leaves with modern leds and usually one of the first signs is that the edges of the leaves start to curl down abit and your leaves aren’t doing that at all, so it could be a little over watering problem rather than the leds making your plants look abit pale.

Yup will try this too, i have noticed thoose green algae before and worried about them. Hope this works. Thx!

 

[f-e]

I think the drying out might be the real key here.

Regarding 200K, that's often seen as acceptable for plants. However coco is a K source. Canna coco is worth about 100ppm. This is why Canna put about 55ppm in their feed. In their feeds for other substrates 160ppm is more common. They know about this 100ppm from the coco being available. Which is why you have 300ppm. Which is well into the region of toxic for some plants during peak flowering demand.

I pulled K entirely for 4 or 5 days during peak K usage, then did a runoff lab test. I had 90ppm K coming out the coco, while they were eating it. The older coco gets, the more it decomposes and this K supply increases. Keeping it sodden will likely be releasing more than the typical 100ppm. There will also be high levels of sodium if it's Asian coco. This is putting a lot of pressure on other nutrients.

Drop the K and start with a wet dry cycle, and that might fix it. It will certainly be a good move. From there we can get another look at what is happening.

 

[troutman]

Never hurts to raise the lights a little until the plants recover.

 

[GoatCheese]

Yup will try this too, i have noticed thoose green algae before and worried about them. Hope this works. Thx!

If you get too much of that algae stuff growing – so much that it actually starts to form a thin layer on top of the coco or soil, it’s good to scrape it off and replace it with fresh coco/soil cause it can actually block the substrate from ”breathing” and won’t allow enough aeration of the medium.

 

[4$gMn20]

I think the drying out might be the real key here.

Regarding 200K, that's often seen as acceptable for plants. However coco is a K source. Canna coco is worth about 100ppm. This is why Canna put about 55ppm in their feed. In their feeds for other substrates 160ppm is more common. They know about this 100ppm from the coco being available. Which is why you have 300ppm. Which is well into the region of toxic for some plants during peak flowering demand.

I pulled K entirely for 4 or 5 days during peak K usage, then did a runoff lab test. I had 90ppm K coming out the coco, while they were eating it. The older coco gets, the more it decomposes and this K supply increases. Keeping it sodden will likely be releasing more than the typical 100ppm. There will also be high levels of sodium if it's Asian coco. This is putting a lot of pressure on other nutrients.

Drop the K and start with a wet dry cycle, and that might fix it. It will certainly be a good move. From there we can get another look at what is happening.

Im gonna try with this formula, will tell you if it works

 

[f-e]

You zinc looks low.
Cu is high
Mo a typo?

 

[SuperNice]

.

 

[f-e]

I keep forgetting to ask. Is this use of a KB light, also your first use of LEDs for this purpose?

I briefly had it working, but once my plants no longer saw HIDs they morphed into plants that didn't like canna coco anymore. Years of changing my methods to make it work, eventually showed me I needed to leave coco. Now I'm undoing all that I changed. Making great steps forward. Or rather, back to where I was in the beginning.

It's just so salty. In bigger pots, where the plants roots hung out the bottom into a reservoir of runoff, it worked. In smaller pots that contained all the roots, it wouldn't. That reservoir has shown to be of interest in soil to. Like DWC for the long roots, but with most roots in the pot that can wet/dry and so not rot. I suspect the hempy's might be quite suited to LED.
It's all just personal findings right now. Except for the others who also came out of coco as they found it didn't work after buying LEDs. Though it can work, certainly. Which might be a divide not between growers, but between the coco source. Coco from the Americas is nowhere near as packed with sodium as coco from Asia. One being grown near the ocean, and one inland. Na will replace your K. Pre-LED we would go in high with our feed to make that coco's additions less meaningful. Since LED we are also raising the Ca. It's becoming a competitive soup of Na K and Ca that's hard to balance. It's just spiraling. N Mg Fe and Zn will visibly suffer, among a host of signs that would puzzle anybody. Or... so it seemed to me.

Have a go. If you can't make it work, don't overlook the idea of coming out of coco. Soil and hydro users have had a lot less drama under LEDs

 

[4$gMn20]

You zinc looks low.
Cu is high
Mo a typo?

Yes edited, had an error with selected watter, I am thinking of acquiring magnesium nitrate to provide more nitrogen during growth up to 2nd week of flowering. With that formula i will have 4:2:1 ratio of K Ca and Mg, thats correct counting the 100 ppm of k that the coco gives approximately? Thx a lot

 

[4$gMn20]

I keep forgetting to ask. Is this use of a KB light, also your first use of LEDs for this purpose?

I briefly had it working, but once my plants no longer saw HIDs they morphed into plants that didn't like canna coco anymore. Years of changing my methods to make it work, eventually showed me I needed to leave coco. Now I'm undoing all that I changed. Making great steps forward. Or rather, back to where I was in the beginning.

It's just so salty. In bigger pots, where the plants roots hung out the bottom into a reservoir of runoff, it worked. In smaller pots that contained all the roots, it wouldn't. That reservoir has shown to be of interest in soil to. Like DWC for the long roots, but with most roots in the pot that can wet/dry and so not rot. I suspect the hempy's might be quite suited to LED.
It's all just personal findings right now. Except for the others who also came out of coco as they found it didn't work after buying LEDs. Though it can work, certainly. Which might be a divide not between growers, but between the coco source. Coco from the Americas is nowhere near as packed with sodium as coco from Asia. One being grown near the ocean, and one inland. Na will replace your K. Pre-LED we would go in high with our feed to make that coco's additions less meaningful. Since LED we are also raising the Ca. It's becoming a competitive soup of Na K and Ca that's hard to balance. It's just spiraling. N Mg Fe and Zn will visibly suffer, among a host of signs that would puzzle anybody. Or... so it seemed to me.

Have a go. If you can't make it work, don't overlook the idea of coming out of coco. Soil and hydro users have had a lot less drama under LEDs

No, I have always used coco with these KB leds. I have previously grown in soil with LEDs other than KB and have had fewer problems but I needed to switch to coco because temperatures are mild where I live and the soil did not dry out easily. I needed to switch to a type of substrate that would dry out faster and had seen quite a few people get good results with coco and quantum boards.
Interesting what you say about the source of the coconut, is there the possibility of choosing less salty coco from the Americas?
Discarding the soil for mild temperatures
I could try using a hydroponic system and the original jacks 321 hydro formula with these KB leds.
But I still want to make Coco and Qb work

 

[f-e]

I'm not sure if 4:2:1 exists anymore. It doesn't at the labs I use, or in the material I read. Where studies are published regarding individual levels of anything, there is a base feed used, and the one variable in question is tried at different levels. I'm of the school that says there should be enough, and with a plant as selective as ours, that really should be enough effort from ourselves. Reading the more involved threads here, people are often finding there way to Ca numbers very close to the K ones.
N in flower isn't something I avoid. I don't want excess, but I don't try and run it low. N is yield. I see many people pull the N, then drop the leaves below bud formations that can't link up. K becomes excessive and they seem to see some sort of senescence, where I see dead stuff.

Are they perking up after a dry back? It been a couple of days now. I would hope to see some good looking new growth.

I really don't want to get too involved here. I walked away as I couldn't make it work myself. Maybe you can do better than I did without my help. I'm just sharing a few things I know, and you can take from it what you thinks useful. Your plants just kinds look like many others struggling in coco under good LED illumination. One of the best comments here was turn it down. Everybody likes a rest.

Bill Fathering has a good thread about cheap nutrient lines, that offers a few growers findings. I think the jacks hydro guys are increasing the calnit, for the cal. While reducing the Mg, which really is quite high with jacks. It seems a common theme. Though I'm a bottle fed guy, so it's purely academic for me. I don't remember exactly.

Canna Coco holds 'a lot' of water. Wet weights of pots are higher than that of Canna Terra, and dry weights lower than that of Terra. It's really not well draining at all. It's coco peat.

 

[TPFTFW]

Epsom foliar 1/4 tsp per gallon
Have you tried foliar yet not just feed