COCO COIR Need help with rusty spots on leaves (autoflower)

[GreenAlchemist]

I’ve been noticing some rusty spots developing on The leaves of my Bloody Skunk autoflower, And it’s starting to concern me (as this is the one I’m most excited for).

Some info about the grow:

Fully organic with dry amendments.

Age: 46 days old from seed (sprouted Nov 12)

The plant is in a 3 gallon fabric pot with coco coir amended with Gaia Green 4-4-4, and 2-8-4, perlite, worm castings and mycorrhizae.

Day 38; top dressed for flower with 50-50 blend of Gaia green 444 and 284 (2 Tbsp per gallon) a cup of worm castings and A dusting of mycorrhizae. Watering in slowly with a Ph of 5.8 - 6.2

Temp and Rh is optimal, but had to raise the light up as it stretched within 12” of the light. It’s still a little closer than I feel I’d like, but I’ve run out of raising room.

I’ve included photos of the plant, and of the amendments I’m using (as well as what I have available in my arsenal to use)
if anyone has any familiarity with organic growing in coco / organic dry amendments, I’d love to hear your feedback!

[BR2K]

I didn't read how much Calmag supplement you give your harem. My first two grows, I couldn't figure out what was wrong. I kept getting these spots, similar to yours. The problem was in the software...between my ears. I read Nebula's guide for coco-coir but neglected to add enough for TWO gallons. Once I corrected, no issues.

We're a bit different. I'm lazy, just going by what GWE recommended and not worrying too much. It's a journey, right? I hope this helps and HAPPY NEW YEAR!!!

[YYCannabis]

https://www.growweedeasy.com/cannabis-plant-problems/potassium-deficiency

Since you’re well into flowering, it looks to me like a potassium issue. If it’s *ONLY* on older leaves, you may have already beat it. If it’s on *NEW* growth you need to up your ‘P’ a bit.

[ChadWestport]

P is phosphorus, K is potassium

[YYCannabis]

LOL...I can’t believe i did that. Damn that medicine i grow is good. 😂

[ChadWestport]

I use to do the same all the time, trust me. They both start with P dammit! In my head, I connected the P to the color Purple, which your leaves will get if you lack Phosphorus. P - purple - phosphorus

[PLreef]

I'm growing bloody skunk autos as well. Also fully organic, gaia green dry amendments too. I noticed small rusty spots started appearing around week 3 or 4. I started adding cal/mag into my water and it seemed to stop it from getting any worse.

[GreenAlchemist]

Thanks everyone for the advice! It’s my first time going fully organic and with dry amendments, after reading these comments I’m now realizing I left out calmag.
I’m planning on picking up some dolomite lime to help with it, unless there is another organic product/method that is more recommended. I’d like to help keep the microbiology in my medium thriving, so I want to avoid any chemical nutrients.

the bottom leaves seem to be unaffected, but also the new growth does not seem to be either anymore, I’ll make sure to slightly raise Ph for the Organics. I’m hoping with the Ph raise that it will unlock the calcium it does get from my water source.

(PS: I should mention that I do the same to all 4 auto’s in my tent, and only for the bloody skunk seems to be lacking calcium, though I’ll make sure this issue doesn’t arise in the others as well)

[PeterMatanzas]

Is cal-mag part of an organic solution? I'm running living soil in my current grow and read that cal-mag is no go on organic grows.

[GreenAlchemist]

It’s true the cal-mag nutrient solutions are a no go for organic, however there are some organic alternatives that can offer cal-mag organically. Dolomite lime is one I intend to add into my amendments, (can’t believe I forgot to have that added before) it can raise the Ph of soil so it’s recommended you monitor that.
I’ve heard of others alternatives like oyster shell powder, but I can’t seem to find that locally where I am.

[PLreef]

GreenAlchemist, how often to you add dry amendments during flower and how much. Im just learning myself.

[GreenAlchemist]

During week 5 (from sprout) Is when I like to first top dress for flower
I put a 50-50 ratio of 4-4-4 and 2-8-4 in (2Tbsp per gallon on medium) so in total with the 3 gallon pot, 3 tablespoons of 4-4-4 and 3 of 2-8-4. After I scratch that into the surface I add a cup of worm castings and a dusting of mycorrhizae and mix in again, then water in carefully (to ensure it soaks in and doesn’t just float to the top)

In 3 weeks from when I last top dressed, I’ll do it again with 2 tablespoons per gallon, but with a 30/70 ratio (30% - 444, 70% - 284) along with worm castings and mycorrhizae again.
I’ve been using a small guide for Gaia Green I found Online to help me remember ratios etc, I’ll include it below.
I hope the bloody skunks in your grow are doing awesome!

[ChadWestport]

If it's not calcium deficient, I'd like to go with Phosphorus deficient for $200 please

[GreenAlchemist]

GreenAlchemist, how often to you add dry amendments during flower and how much. Im just learning myself.

Here is the little guide I use for ratio etc.

[PLreef]

Thanks. This is the same guide I've been following.

[GreenAlchemist]

Hoping this works! Today I picked up some dolomite lime, and top dressed her with 1 tablespoon, then scratched in and watered with around 6.2 Ph water dechlorinated, which was mixed with a tablespoon of black strap molasses. I’m hoping this helps solve this little problem (I hesitate to say its only a Ph problem as everything gets the same soil/amendments/water/treatment, and this is the only with these issues) but I am slightly raising the Ph

[PLreef]

My girls reacted really well to the molasses. Perked up in a couple hours. Very healthy looking.
I came across this. Elemental Powdered Calmag by Roots Organics 0.25-0-0.1
Goes well with growing organic and as a top dress like the other dry amendments your using. Im gonna order up a bag myself.
Good luck, let us know how you make out.

[YYCannabis]

It’s potassium deficiency as i mentioned earlier.

[GreenAlchemist]

Here’s an update / photos post of how she’s doing.

The other day I top-dressed 1 tbsp of dolomite lime, a dash of mycorrhizae and watered in with blackstrap molasses water. (I checked all my nutrients and it’s lacking cal-mag. Also I know I’m missing calcium with growing in coco, So I wanted to make sure there was a source in my soil.)

I don’t feel it’s potassium as I top-dressed Dec 19th with 40% 4-4-4 and 60% 2-8-4 (2tbsp per gallon) A cup of worm castings and mycorrhizae.
I feel if it is potassium I should have caught it well in time with the recent top dressing, but maybe not enough?

However I’m noticing a much lighter green on lower fan leaves, little yellowing between leaf veins, the rust spots don’t seem to be getting worse but I do notice on a few more leaves (lower)

I know many feel it’s a Ph issue but I haven’t ever needed to Ph up or down it (as it sits around 6.2 naturally after dechlorination) I’ve heard it’s not so beneficial to swing Ph with organic live soil etc. So I’ve left it that way (I feel I should mention the other 3 auto’s have none of these issues with the water)

should I be top-dressing her every 2 weeks instead of 3 to avoid deficiency? Any advice or comment is very appreciated

[9fingerleafs]

just like i commented above, main issue is calcium and its probably due to low ph, adding dolomite as a top dress can raise the cal mag concentration too high and create a new set of problems, organic soil grows are based on complicated relationships between fungi bacteria and plants, this issues are adressed with liquid nutrients for this run and then make changes to the next batch of soil, dolomite should be mixed into the soil, i dont really know what exactly you need to do to balance your soil because i dont know whats in it. but i think your best chances are to feed some liquid calmag at normal dose and raising the ph of the solution to 7 using baking soda for a few weeks until its time to flush.

[ChadWestport]

Top dressings usually take a bit longer than a liquid nutrient to become bio-available to the plant. Quick fixes I usually order as - Foliar, liquid nutes, dry amendments.

[PLreef]

GreenAlchemist how are your plants doing? I ordered roots organic elemental calcium/magnesium and it came in today. I'm using it as a top dress feed. Hopefully my girls react well to it.

[GreenAlchemist]

Hope they react well to the new mix, Let me know how it works for you, I’ll be checking that stuff out for sure for future grows! I’m hoping to keep this all 100% organic