Name that deficiency/toxicity - Please

[Major PITA]

HELP!​

Hey guys, I could use some more eyes and ideas.

My Zamaldelica cross (23 weeks into veg outside), in just the last two weeks has developed rust spots that spread to the leaf margins. This is the only plant showing this problem even though all are in identical soil. It started on a single branch about midway up - not the old leaves and not the new leaves. It has since spread to other branches and is also spreading both up and down the affected branches. Other parts of her still look perfect, but I'm thinking that won't be the case in another week or two.

So far, I tried some Cal-Mag. After waiting nearly a week and seeing the problem spread I gave her some bottled water soluble nute's with 'P' and 'K'. I used bottled stuff thinking it would be quicker to act and easier to flush, if needed. Since then, I've given water only since the nute's aren't helping. I'm not great at reading nute deficiencies, but what I see appears to be calcium, magnesium, or possibly manganese or potassium deficiencies.

Up until this problem started she was getting water only since the soil is amended and has been keeping all my plants pretty happy.

Any ideas?

 

[Fuzzy Duck]

I'd more likely say K-potassium.

It don't always effect the older leafs first & some times resembles nutrient burn which did cross my mind when i first glanced at it.

Liquid nutrients would be a quick fix in the sort term but as your are growing in amended soil perhaps look around for an amendment with with a good level of potassium in.

 

[Major PITA]

The majority of the plant looks fine and it has grown another 2' since my last post. New leaves are OK. I've been loading up on the potassium but the problem continues. These photos kind of shows the progression. I find it weird that only some branches are affected. It starts in the middle of a branch and works its way up and down. Also, it starts with rust spots in the middle of the leaf that spreads to the edges and tip.

A very close relative to this plant is growing right next to it, in the same soil, and it doesn't have this problem. Any more ideas/comments? I'm growing is a Supersoil derivative with an apparent PH of 6.4.

 

[Emilya Green]

I am also going to lean toward a potassium deficiency, especially if you have a lot of calcium in the soil. I think i would give her a good all purpose 5-5-5 feed and see how she responds. Odd it is only that one... what is special about her... more sun, shade, on a grade, next to a pine tree?

 

[Major PITA]

I am also going to lean toward a potassium deficiency, especially if you have a lot of calcium in the soil. I think i would give her a good all purpose 5-5-5 feed and see how she responds. Odd it is only that one... what is special about her... more sun, shade, on a grade, next to a pine tree?

I was giving her some Cal/Mag because initially it looked more like a 'Ca' deficiency than 'K' to me. All rust spots were in the interior of the leaves - not along the edges. I stopped that nearly a month ago.

The things that are different for her (a Zamaldelica crossed with another pure Sativa):
Supposedly a light feeder for 'N'. I do have a Golden Tiger (the male used to create ZD) cross next to her.
ZD is in the center of my grow. She has four plants around her, but they are each 6'+ away.
ZD is the tallest of the plants at 8-9'.
ZD and GT are both from seed. Others are from cuttings.

What they all have in common:
No trees or other plants close by
Same slope/grade (a 2' diameter around each is flat with a slight grade beyond that area).
Same soil.
Same weather with highs ranging from about 80 to 100+ over the last two months. More mild than usual this summer, typically 85-90.
Same watering schedule and technique, now using 8 gallons every other day. I know this sounds like a lot, but the 75 gallons of soil for each is porous and sits in sandy soil. They wilt by the third or forth day, depending on the heat. The water is from our well (130 PPM hardness and no chlorine).

That's all I can think of for now. I appreciate that you took the time to mull this over and reply.

 

[Emilya Green]

I would think then it has to be related to her being the biggest one, and the most active, and the one first to experience the deficiency. Now the task is to figure out if the soil is lacking something, if there are enough microbes to get it to the plant, and if there is something creating a bad balance in the soil. It is here somewhere... we just need to figure it out. What all did you put in that supersoil mix?

 

[Major PITA]

I would think then it has to be related to her being the biggest one, and the most active, and the one first to experience the deficiency. Now the task is to figure out if the soil is lacking something, if there are enough microbes to get it to the plant, and if there is something creating a bad balance in the soil. It is here somewhere... we just need to figure it out. What all did you put in that supersoil mix?

I agree. Whatever is going on is almost certainly due to my soil mix. This is my first year doing a DIY soil.
The mix is: 8-4-2-1 using: sawdust - pumice - sandy loam soil - compost
The above base soil mix was amended (in no particular order) with: EWC, bone meal, Hi 'P' bat guano, blood meal, feather meal, soft rock phosphate, Epsom salts, dolomite lime, Azomite rock dust, kelp meal, neem meal, myco, alfalfa meal, and humic and fulvic acids. It was mixed then "cooked" for four months prior to use in mid-May. The sawdust isn't your every day wood byproduct. It is extremely well aged = many years old and very well composted. It has a chocolate color when dry, and looks very much like peat moss.

From three weeks ago. ZD is in the center. Pine and cedar trees are about 30' away.

All other plants appear very happy. Brix readings from lower fan leaves are in the 18-22 range.

 

[Emilya Green]

I keep centering in on the sawdust. I urge you to get a soil test done and see if the sawdust has managed to lock up your phosphorus or potassium. Read this article to see some of the possible interactions. Considering the length of time your soil has been cooking, it would be about now that these interactions would start to happen, as the sawdust really starts to break down. A soil test should tell you what you need to top dress with to solve this imbalance.

https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/8601/tec_bul_49_.pdf?sequence=1

 

[Major PITA]

I keep centering in on the sawdust. I urge you to get a soil test done and see if the sawdust has managed to lock up your phosphorus or potassium. Read this article to see some of the possible interactions. Considering the length of time your soil has been cooking, it would be about now that these interactions would start to happen, as the sawdust really starts to break down. A soil test should tell you what you need to top dress with to solve this imbalance.

https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/8601/tec_bul_49_.pdf?sequence=1

I agree the sawdust is my primary concern. Since there is no place locally to get a soil test done, I think it is too late for this season. I do plan on having it tested after I harvest in order to know where I'm at for next year.

The odd thing is all the other plants are good with it. This sawdust is not likely to break down much. It is 15 years old and has had 'N' added to it a couple of times. It is about as composted as wood fiber gets, IMO. It was 7 months ago when I amended and mixed it. We use it in our veggie garden and is doing fine there, as well.

I am looking forward to a soil test this winter. Currently, PH tests look like it is at 6.3 - 6.4.

 

[Emilya Green]

I think based on that article, I would try top dressing with a high P and K source and continue with fish juice to keep the nitrogen working on that wood... but yes, a soil test is going to answer the mystery I think.

 

[Major PITA]

I think based on that article, I would try top dressing with a high P and K source and continue with fish juice to keep the nitrogen working on that wood... but yes, a soil test is going to answer the mystery I think.

The article is a good read, but like most sawdust studies, they use new sawdust. It is very unlike the stuff that has been composted for many years. In fact, because it is so prevalent here, this kind of aged sawdust is locally sold as a soil less gardening medium. It is used a lot with good results. We use new sawdust to kill weeds and undesirable plants. While composting, it pulls so much 'N' from the soil that the plants starve from a lack of it.

Thanks for the assist. I look forward to getting a test done. Hopefully that will get to the bottom of it. Right now I'm still leaning toward a 'K' shortage, or just plain old nute' burn since ZD is a light feeder and the other plants seem to love the stuff.

 

[Emilya Green]

I suggest asking Heirloom and Conradino their opinions on this too. Not sure that I have been any help to you. Good luck though, and I think you have it figured out, and I will be very curious to hear what that soil report says.

 

[DeanB]

Incorporated sawdust had a definite loosening effect on soil and
also tended to retain soil moisture for longer periods between irri-
gations.

Maybe she needs watered less than the others?

 

[electro gypsy]

My guess is zinc and maybe some copper deficiency.. maybe a little of some of the other things mentioned. My largest Durban Poison just went through this and is improving now. Fox Farms Kelp Me Kelp You (lol). Use a few times with your PK regiment It's good stuff. Sold me on making my own soon.



*Yeah.. I think I'd go with less watering also.. I'm really thinking an issue with water transference.

 

[Major PITA]

I suggest asking Heirloom and Conradino their opinions on this too. Not sure that I have been any help to you. Good luck though, and I think you have it figured out, and I will be very curious to hear what that soil report says.

Thanks again!
Conrad is following my journal. You definitely helped. IMO, another set of eyes and perspective is always useful when in doubt.

Incorporated sawdust had a definite loosening effect on soil and
also tended to retain soil moisture for longer periods between irri-
gations.

Maybe she needs watered less than the others?

I don't think she is over-watered. I watch for signs of early wilt before watering. With buds about to set, I'll probably be watering even more.

My guess is zinc and maybe some copper deficiency.. maybe a little of some of the other things mentioned. My largest Durban Poison just went through this and is improving now. Fox Farms Kelp Me Kelp You (lol). Use a few times with your PK regiment It's good stuff. Sold me on making my own soon.

Thanks! I'll check it out. I've used fish fert's and do have kelp meal in the soil as well as Azomite and other goodies trying to cover the trace mineral needs.

You all rock!!

 

[McCdive]

I know you said the well water was at 130 ppm, but what's in it? High iron? Calcium? Mag.? Ph.?
I realise your other plants are doing well, but if it's a slight burn or lack of something, it's good to know what you're starting with. Just a thought, but you may want to have your water tested.

(sorry, I think like a plumber. lol)

Hope things work out, Andy.

 

[Major PITA]

I know you said the well water was at 130 ppm, but what's in it? High iron? Calcium? Mag.? Ph.?
I realise your other plants are doing well, but if it's a slight burn or lack of something, it's good to know what you're starting with. Just a thought, but you may want to have your water tested.

(sorry, I think like a plumber. lol)

Hope things work out, Andy.

We do have our water tested from time to time.
This was the result of the most recent test. Being a well, it varies a little but the results have been fairly consistent over the years. It is a little high in copper but nothing remakable.
Measurements are in ppm:

Aluminum 0.0206
Arsenic 0 (ND)
Barium 0.0124
Boron 0.461
Cadmium 0 (ND)
Calcium 31.8
Chloride 1.6
Copper 2.01
Fluoride 0 (ND)
Hardness 121
Iron 0.656
Lead 0 (ND)
Lithium 0 (ND)
Magnesium 10.8
Manganese 0 (ND)
Nitrate Nitrogen 0.360
Sodium 12.1
Sulfate 9.65
Zinc 0.116
PH 6.98
Specific Conductance 240 uS/cm = 120 ppm

 

[Bumble]

Just a quick question, what are you using to lower your ph? Noticed it'salmost 7 but you stated it's at a 6.4. I am running well water, also at a 7 and I'm using distilled white vinegar. Brought it down to about 6.5. But is vinegar bad for my plants in other areas, like Taste?

Peaceful blazing...

 

[Major PITA]

Just a quick question, what are you using to lower your ph? Noticed it'salmost 7 but you stated it's at a 6.4. I am running well water, also at a 7 and I'm using distilled white vinegar. Brought it down to about 6.5. But is vinegar bad for my plants in other areas, like Taste?

Peaceful blazing... ��

The big plants don't get any PH adjustment. It is just the water out of our garden hose. They have my soil mix. It is buffered and at about 6.3 - 6.4 PH to begin with.

The plants in pots get GH Flora Nute's. These nute's pull the PH down. I use a 1/2 strength concentration and it puts the mix at about 6.3. In the past, when I did need to adjust PH I used GH PH Down (phosphoric acid).

 

[Bumble]

Thanks. I'm pulling newbie stunts off all over I'll tell ya! Lol. Over pollination, wrong type training, over watering, male was a female(really!) and now I'm just wondering if my ph lowering method might ruin the taste of these buds. Lol. I'm definitely going to have to change it. Possibly not cut corners anymore when it comes to soil and root development.

Peaceful blazing...