Shogun coco - magnesium issues.

Hello,

I'm a newbie to all of this, although having grown vegetables and alternate plants over the years.

I've got 4 autoflowers under a DIY light (22 samsung q-series gen-2 strips) dimmed down to 60% and I'm having constant mag issues.
I've been looking at the bottles for shogun coco a&b and see no mentions of magnesium, but their calmag only has nitrogen, calcium, and iron listed, too?

I've tried addressing this by adding calmag at 1ml/litre which resolved a calcium issue, but the magnesium issue persists in spite of foliar feeding as well.
I can't find any safety data sheets for these nutrients, but with no mentions of magnesium, would I be wrong in assuming it either isn't present, or it's in low quantities which don't warrant a mention?

I'm now supplementing with magnesium sulfate, which I've added 150ppm (0.15ms ec) as well as giving a foliar feed of mag sulfate and liquid seaweed with trace minerals.

Has anyone else had constant magnesium issues with shogun coco, or am I just doing it wrong? I've been feeding 1.1EC in week 3 and plants look good other than a what looks to me like a mg deficiency. Slightly stunted given a cal issue, but catching up.

Got pics?

Hollatchaboy said:

Got pics?

Click to expand...

Here's two plants, one banana purple punch (suspected mg def) and one amnesia zkittlez which looks happy to me after adding calmag and magnesium sulfate. Was showing the yellow veins before adding magnesium sulfate.

I can't find the npk ratios of that range but you can guarantee there's magnesium in the base.

There's also magnesium in the calmag , just not sure on the ratio.


Which leads me to ask, what's the environment like?

coreywebster said:

I can't find the npk ratios of that range but you can guarantee there's magnesium in the base.

There's also magnesium in the calmag , just not sure on the ratio.


Which leads me to ask, what's the environment like?

Click to expand...

Thanks for the reply.

I thought there would have to be magnesium in it as well, but it's completely missed from the label and as you've seen, their safety data sheets/analysis are no where to be found.
I've seen their soft water feed chart advises using one of their foliar sprays alongside calmag and base nutes, so I don't think there's a large amount in there.

My environment is pretty stable (I think) -
Temp - average 22 Celsius
Humidity - 64%
Baseline water test- 150ppm
Ph - I allow it to swing from 5.8-6.3 before adjusting it back down again. I read calcium is more available at higher pH, so wanted to encourage higher accessibility.

Light is reading 450 par at canopy height right now, although this is using my phone and an app so I wouldn't consider it an accurate reading.

Nutes wise I'm running-
Coco a&b - 1.2ml/l
Calmag - 0.75-1ml/l
Silicic Acid - 0.5ml/l
Magnesium sulfate - adding up to 150ppm to try stabilise this deficiency.

Plants are fed via wilma/origin system, feeding 4 times per day for 15mins each time.

Medium is 70% coco 30% clay pebbles.


What will be interesting is within the next week or so I have some masterblend coming, which according to their ratios has a pretty high baseline of cal/mag (with cal nitrate and mag sulfate) - it'll be interesting to see how the plants react to this transition, and if supplementation will be necessary.
I unfortunately baited into the multiple bottles thing, but I now realise those multiple bottles are just divided nutrients as a money making mechanism. I thought I'd try treating the girls like I would vegetables and with cannabis having similar nutritional requirements to tomatoes (from what I've read), treating their feeding similarly.

What stands out there is your temps

22c is 71f. Way below where you should be.

Try over 80 f under LED , see if that improves things.

The only other thing, are you checking your res in your wilma? Is your EC raising, your ph remaining stable?

coreywebster said:

What stands out there is your temps

22c is 71f. Way below where you should be.

Try over 80 f under LED , see if that improves things.

The only other thing, are you checking your res in your wilma? Is your EC raising, your ph remaining stable?

Click to expand...

I'll give this a go! When my temps were around 25celsius I had some upward leaf curl which I thought may have been heat stress, so I lowered the temps down and could have inadvertently caused the issue!

I am, yes, the PH swings from 5.8 up to 6.3-4 before stabilising and I'll drop it down to 5.8 again after around 5 days of initially mixing.
EC goes down consistently and when I see a note able dip in ec I'll top up the res, or mix a fresh batch with a higher concentration.
Res is cleared every week and fresh mixed.

I've amended the environment now this

The 93f is me adjusting things. When it hits 86f the space heater will turn off until it hits 79f before activating again.

I get a feeling the previous leaf curl was down to light intensity and not heat stress.

Thank you very much for pointing out the temperature issue, I didn't factor in the enhanced transpiration rate requirement attributed to the light intensity from led lights. Makes a lot of sense!

NullPointer500 said:

I've amended the environment now thisView attachment 5382741

The 93f is me adjusting things. When it hits 86f the space heater will turn off until it hits 79f before activating again.

I get a feeling the previous leaf curl was down to light intensity and not heat stress.

Thank you very much for pointing out the temperature issue, I didn't factor in the enhanced transpiration rate requirement attributed to the light intensity from led lights. Makes a lot of sense!

Click to expand...

Sweet, I'd be surprised if it didn't improve considerably over the next week.

Keep doing what you've been doing with the wilmas, they're a good system when ran right.

Though later on you might want to get a digital timer and run more frequent watering but less duration.