Possible cal/mag issue?

[JonathanStrange]

Good evening fellow herboligists . I’ve had a few small plants getting started during their seedling phase in a Sirius style top-fed DWC system and I noticed one of them, a Durban poison if it matters to you all, developed some spots while I was away this weekend. I just want to make sure I get out in front of it if this is a potential problem. The plants appear quite healthy in all other respects, but I figured I’d ask some people with more experience. Some parusong of the web makes me suspect it could possibly be a cal/mag deficiency, but I’d love another opinion. Thoughts?

Thanks in advance.

Cheers!

S.

[Campesino]

Yeah, looks like early Cal deficiency. May be caused by low pH (what are you running?)

[DoctorJohnson]

That does look like it could be a calcium deficiency, but that plant is awfully young to be showing a deficiency.

What are you feeding it?
How soft is your water? PPM out of the tap? Are you using RO water? If you don't have to a PPM meter, do you have to add a lot of pH Down to your tap water (a sign of hard water). I ask because hard water has more calcium in it, so you would be less likely to have a deficiency.

[Campesino]

I had Cal issues with seedlings at that age and I always add CalMag! Had to do with pH... If pH is not buffering to 6.2 then Cal is largely inaccessible. I have actually found them to be really sensitive to Cal at this age in Coco or Hydro grows at pH below 5.9.

[JonathanStrange]

Doc, the ppm our of the tap tends to hover between 150-160. It’s not ro water, but it does sit out for several days in order to allow any chlorine to gas off. I do typically have to adjust the ph down, but I’m not sure if I’m using “a lot”. Typically the water out of the tap is near 7.0, and I try to keep the res somewhere between 5.8 and 6.2. I check it twice daily. As for feeding, they’re receiving flora trio at approximately 1/4 to 1/2 strength compared to what the bottle recommends. I’m following Nebula’s guide for what to feed them im hydro, printed in a handy excel sheet (attached for convenience).

Campesino, thanks for the details. Maybe I need to tighten up my ph even further.

Cheers!

S.

[Campesino]

No problem.
Are you adding the "Optional" CALiMAGic?
I'd recommend it and if using with Flora Trio, CALiMAGic should be added to the water first (before Micro! despite what Nebula's schedule would lead you to believe).

I have also had success using CALiMAGic as a foliar. I mixed at regular strength (5ml/gal) at pH 7.0.

[DoctorJohnson]

150 PPM is a reading that betokens moderately hard water, though I would expect a higher pH in that case. Maybe something else is raising your PPMs? (Iron?) You can check your water utility's website.

BTW, I have never bothered with letting water sit to off-gas and never had any problems (that I know of, anyway). The Cl levels in tap water aren't very high. And in lots of municipalities they don't add Cl as gas anyway (they add it in a stabilized form) so it doesn't off-gas. Again, your municipal water website should tell you.

Nebula's diluted nute sked has worked for me.

There is a lot of voodoo about pH. Remember that modern fertilizers are compounded with multiple versions of some nutrients and also chelated and buffered, just so that they DO work across a broad range of pHs. For some reason people don't seem to want to hear that sometimes.

Here's a really good read that used to be at the GH site: http://www.simplyhydro.com/Advance_Nutrient_mgnt.htm Here's a quote:
"You can safely allow pH to drift between 5.5 and 7.0 without adjustment. in fact, constantly dumping chemicals into your system to maintain a perfect pH of 5.8 to 6.0 can do a lot of damage."

[Campesino]

I agree with allowing the pH to range and, indeed, I think we may be dealing with an example of the "damage" that can occur when it does not ever drift high enough. I wouldn't let it get as high as 7 in Coco or Hydro though - but agree in principle

[JonathanStrange]

I haven’t been adding the cal/mag supplement. Perhaps I’ll give it a shot.

Thanks!

[DoctorJohnson]

> CALiMAGic should be added to the water first
That's a good point. According GH (though you have to hunt for it) CALiMAGic first, FloraMicro second, then everything else. (I think silica gets added early too if you ever use that.) I do believe it's because the ones that go in first are in alkaline solution and the later ones are acidic.

[Campesino]

Yes!
Silica First - I add it several hours before the rest
Cal/Mag second
Micro third...

See the note on the left side of this GH feedchart: http://gh.growgh.com/docs/Feedcharts...TW_03216am.pdf

[WeirdWiredWolf]

Campesino, thanks for that feedchart, now I know where I screwed up mixing one batch of nutes (wrong order).

[DoctorJohnson]

> Silica First - I add it several hours before the rest
So Campesino, I assume you are another one of those satisfied Si users I keep running into? Any anecdotes/thoughts/cautions/advice?

[Chefbjy]

Interesting...he's probably trying to get more seeds to sprout 😆.

[UrbZ]

Sorry everyone. Been absent for a few days. I actually didnt have time to germ new seeds yet. I got a new girlie. Shes been taking most of my free time. Germining will start again tomorrow my first real day off in 2 weeks.


I add my silica to my r/o first, I let it sit usually 8 hours before adding anything else. Silica is basically a solid form just microscopic.. When adding into water it usually takes awhile for the silica to actually break down to small enough particles to be absorbed. I find When adding it to close to others my ph will fluctuate. If I add it it first and let it sit my ph will stabilize better than adding it right away. I figure DoctorJohnson is right it has to do heavily with the alkilinity vs. acidity levels reacting.

[Chefbjy]

I don't use ro but that seems logical. Grats on the new girlie. And good luck with germing.

[JonathanStrange]

Thanks for the info guys. I’ll be getting some calimagic soon then. The spots appear to have gotten worse over night 😬. Only on one plane, and only on the first real set of leaves it has grown so far. Pic of new spots attached.

Cheers,

S.

[JonathanStrange]

Gentleman, some follow up questions about cal/mag issues. My plants have been running calimagic for about a week, at what point should I start to see the sadness dissipate? It looks to me like they’re not making any real improvement. I also thought this problem could be a potassium deficiency due to overwatering so I disconnected the auto watering pump and that hasn’t seemed to help. I’m open to any suggestions you all might have.

Thanks!!

S.