Mag deficiency, or overwatered coco?

[Kazooey59]

Hey guys,

So I'm currently running some imported Speedrunseeds genetics, it took a full month to arrive, so I'd be sad if these just straight up die.

I'm running coco/perlite 60/40, solo cups, Canna Coco nutrients + Canna Calmag Agent, RO water. I add Calmag until I'm at 200PPM / 0.4EC, and then Canna Coco A+B until I'm at 1.6EC currently. PHed to 5.8. They also get the full 1.6EC as two fertigations per day, always til runoff (around 30-40ml per fertigation, with a syringe). Temps are at 80-82°F, humidity always around 65-70%. They will soon be transplanted into autopots. I have one already in an autopot, just without the system turned on, she is 100% fine, just a few days older.

It's apparently just the two "Acid Snow" seeds from Speedrun that show problems. The other two Granite Haze F5 are fine, one being the older plant. They all seem to take up the multiple fertigations just fine, but now I feel like something actually might be wrong with the two. It looks like a magnesium deficiency to me personally.

I did some tests, checked runoff EC and PH. Runoff EC was 0.1 higher than input, which is fine I think. Runoff PH came out at 5.6 though, which seems a bit low? I tried fixing this by finally varying in the PH input I use, as I always went for 5.7-5.8PH, rather than going a bit more upwards sometimes. I now fed them with 5.9-6.1PH as of yesterday where I noticed these problems, but I don't know if this will actually fix it, if that's even the cause of these problems. PH runoff is now at around 5.8-5.9

Some people said that I'm straight up overwatering, because of the algae growth. But I heard it's totally fine to do this, and it's totally fine that algae is growing, as this is a synthetic coco grow with high perlite content. They also don't seem overwatered, they're all pointing against the light, seem happy, but the leaves just show problems as of 2 days ago.

I'm scared that things will go wrong from here onwards. I don't want them to die, I was so happy when they arrived. Can someone please tell me what's going on here? I can provide all details if needed.

 

[JP1]

Have you checked your meters calibration? Everything you're doing sounds fine. I wouldn't worry at this point. Focus on the new growth. Those leaves are gonna come off later anyway

 

[Kazooey59]

Have you checked your meters calibration? Everything you're doing sounds fine. I wouldn't worry at this point. Focus on the new growth. Those leaves are gonna come off later anyway

Whoops, forgot to mention the PH pen - Yes, it's 100% calibrated, and always kept in a KCl solution, and washed before- and after every use in RO water. It's a brand new Apera PH60, and for a 4.00/7.00PH solution it reads 4.01/7.04PH, which seems picture perfect. The EC Pen is a Milwaukee Instruments T75, also washed with RO water after every use.

 

[JP1]

Whoops, forgot to mention the PH pen - Yes, it's 100% calibrated, and always kept in a KCl solution, and washed before- and after every use in RO water. It's a brand new Apera PH60, and for a 4.00/7.00PH solution it reads 4.01/7.04PH, which seems picture perfect. The EC Pen is a Milwaukee Instruments T75, also washed with RO water after every use.

Just keep doing what you're doing and see in a week. Seedlings are wonky and what's important is that they're growing every day. If those new leaves start showing issues then it's time to adjust something since those will be the 1st real leaves. Most of what the plant is doing is happening down low and it's best not to chase problems that aren't there. It's not overwatering, and the algae isn't a problem other then it can make a crust and screw up the watering by creating channels the water will run down. But that's later in flower usually and you can just break it up and mix it into the top. The plants will grow, don't stress so much. Coco is very fixable quickly. Start a grow journal on here so it's easy to follow your own grow and it's easier for people to help

 

[Kazooey59]

I just noticed something, but I don't know if this is the cause, as I had those "yellowish" tips before the addition of these lights. Later on, the funky interveinal chlorosis appeared.

3 days ago I got some IR light bars as "supportive IR light" additions, for free, from a friend. They're also exactly for my LED light, so I just threw them in there. I just noticed that the time switch didn't start working, and they were on 24/7 for around 3 days now. They're 8W IR LED bars if that's of any importance. They were supposed to run 30 minutes each day, not 24 hours, so I don't know if they might have caused some of that damage.

 

[idiopathic neuropathy]

From my experiences and articles I've read(i went down this rabbit hole) runoff ph in coco is unreliable in coco. One example, I tested with several plants, I was getting ph results in the 4.5-5.0 range for runoff. I tried to increase the ph through the whole grow, but could never raise it---but the plants grew fine.

 

[Kazooey59]

It sadly keeps spreading. I don't know what this is. It doesn't really look like magnesium to me anymore, it's weird dots / lines, yellowish, squiggly, see for yourself. I think this has nothing to do with Magnesium. 100% sure this isn't a pest or anything.

Any other ideas? It's spreading rather quickly.

Here's my current feeding / mixing schedule:

RO water 0.01EC - Shake & add Canna Calmag Agent until 200ppm / 0.4EC - Stir, let dissolve - Shake & add Canna Coco A, stir - Shake & add Canna Coco B, stir. Check PPM/EC - Check PH, usually it is at around 4.8PH now, because of the RO water - Add Canna PH+ (5% potassium hydroxide), usually just 1 drop of it is enough.

I then water the rim of these solocups with this solution, using a syringe, around 30ml until runoff is the average I use. I do this twice a day. Takes around 5 seconds after watering until runoff starts appearing.

 

[BII]

Do you need to add Ca/Mg with such young plants; and is 200 ppm too much? Is this part of Canna nutes' recommended regimen? Is this in addition to pretreating your perhaps already well buffered coco with cal-mag?

Could be strain-related, with as you report this the only strain affected?

If you can't determine the cause, just hope the plants outgrow this stage. See what happens say in a week when the current embryonic branches and leaves more fully develop. Perhaps cull the plants and move on if they are growing substantially slower that the other strains.

 

[Kazooey59]

Do you need to add Ca/Mg with such young plants; and is 200 ppm too much? Is this part of Canna nutes' recommended regimen? Is this in addition to pretreating your perhaps already well buffered coco with cal-mag?

Could be strain-related, with as you report this the only strain affected?

If you can't determine the cause, just hope the plants outgrow this stage. See what happens say in a week when the current embryonic branches and leaves more fully develop. Perhaps cull the plants and move on if they are growing substantially slower that the other strains.

I use RO water (pretty much 0EC), and Canna recommends a starting EC of 0.4 by adding CalMag in this case as a "starting base". I then stir it all in, and then add the A, then B, until I'm at 1.7EC. I raised the seedlings EC/PPM over several feedings until they hit 800PPM / 1.6EC, and they all seem to do just fine, it's literally just the Acid Snow strains that have these weird symptoms.

My pipes are ~100 years old and I don't trust them, which is why I use RO water to have 100% control over everything

 

[BII]

If the Canna regimen presumes use of unbuffered coco but your coco is pre-buffered or pre-loaded with Ca/Mg, could you be overdosing Ca and/or Mg?

With the adverse effects limited to "just the Acid Snow strains that have these weird symptoms" and you presumably doing everything right, as you note the problem could just be the strain and/or that specific batch of seeds.