Deficiency Question

[eyeswideopen]

My buddy lives right up the street and we're both on the same public water supply. Same LP aero systems, and same nutes in veg. His first round plants developed these rust spots like a zinc deficiency except that they start at the old growth and move up. I have never had this problem in my garden so I can't figure out what's going on. We chalked it up to bad genetics the first round, but now his next round is vegging with healthy cuts and the same thing started happening over the last 3 days since running azamax overnight and then changing the rez. However, azamax was never used on the first run.

Nutes: Calmag, liquid karma, pureblend pro grow

PH 5.8, 900 ppm, temps in the mid 70's, humidity around 50%, Chiller at 68.

I am really stumped on this one and would appreciate any advice if anyone has had a similar problem.

Thanks,
EWO

 

[MIway]

You should try running the rez's for two weeks... at both spots... gut tells me that's the issue... ;-)

 

[eyeswideopen]

What do you mean running the rez's? Running with what?

 

[Dr. Detroit]

It's a calcium deficiency, likely pH related. Use a cal-mag (and only a cal-mag) with properly pH'd water and it'll clear up in a few days.

 

[Snow Crash]

I'm guessing you guys have some hard water, probably a bunch of sodium. If you have a water softener this would be a dead give away.

What's your tap EC at and what's your water report say on Turbidity and the ppm counts on Calcium, Sodium, Bicarbonates, and Nitrates. Filtered water might be the only resolution.

 

[MIway]

What do you mean running the rez's? Running with what?

If you say all other variables being equal... the only thing that stands out is that you are balancing one rez... while he is doing the other, which happens to be having the problems.

Just from that, I would venture to guess what SC & DD are getting at... he's apparently not running his reservoir as well as you... ppm's, pH, top ups, etc... ya dig?

 

[hiboy]

Your basic base fertilizer has most of the needs to grow a healthy plant. There are exceptions, but.... are you doing the minimium of nutes? I dont see a single burnt tip
hiboy

 

[eyeswideopen]

Not sure what's in our water but our of the tap the tds is ~90ppm and has never been an issue at my spot. We actually have an RO not being used because water hasn't been a problem. I should look into the turbidity with my local water authority and find out about the sulfer.

I see what you mean about running both rez's now...I definitely assumed he was doing everything the same because I'm the one that taught him, but I should get in there more often and see what's going on.

As far as feeding, I'm not sure if I'm at the minimum, because I mix my nutes and then go by TDS. I used to keep TDS between 15-1800 depending on strain but found that the plants seem much happier with the lower TDS in the 9-1200 range.

I got some advice today on another forum to add epsom salts to the rez or use as a foliar. Can anybody speak to this?

Thanks for all your help

 

[Seamaiden]

You can try Epsom at the rate of 1/4 teaspoon per gallon of water. If it's a magnesium problem then what's already gone will not correct, the observation should be no further progression of necrosis.

However, I personally feel that it's a calcium issue alone, and I would not use Cal-Mag or any combined product to resolve that issue. Once I separated out Ca and Mg (using a product twice as "strong" as Calplex, but Calplex is most commonly available, and MgSO4, aka Epsom salt) I was able to see exactly what did what. I also discovered that you can alternate feeding each, which allows you to bump up saturation of the other stuff.

I have also found that PBP SERIOUSLY drives pH down, into the 4s, when using RO/DI water. It's not so bad if it's used with my own unfiltered (well, and extremely hard) water.

In lieu of a water report, if you and your buddy are of a mind, you can spend about $25 and get yourselves a Tetra Laborette colorimetric test kit, used for both saltwater and freshwater aquariums. That kit will test pH (though not terribly accurately as compared to a good meter), but more importantly it has tests for two types of water hardness--general and carbonate, as well as NO3 (nitrate, for some reason it doesn't have a NO2 test and IIRC no NH3/4).

 

[eyeswideopen]

Thanks for your help seamaiden. What's PBP?

What do you use that's twice as strong as calplex?

And I'll get myself a test kit.

Thanks again

 

[Seamaiden]

PBP = Pure Blend Pro. I have an organic agricultural product, always forget the name of it. :o BioLink or BioAg or something like that, smells good though.

 

[desertsquirrel]

Yes epsom (MgSo4) is a great source of Mg as well as S (ill post the profile below).

Nute solution should never be mixed with a meter, It is entierly too inaccurate. meters are for monitoring solution not mixing it. Instead use the profile for mixing (pbp/calmag profile below).

I guess its possible its a cal or a K issue, but it looks most like the pics from people with toxins off gassing (from tents or NGW hose). Id look and see what kind of different plastics are in both of the rooms.

Epsom salt, magnesium sulfate, Mgso4:

Mg: 9.8%
S: 13%

1g Epsom salt =

Mg: 98 mg or 98 ppm/liter
S: 130 mg or 130 ppm/liter

or

1g/10 liters =

Mg 9.8 ppm
S 13 ppm

profiles are in easy to use 10 ml/gal form. drop them to 1 ml/gal and play with the math till your profile is how you want it. the greatest effect on your profile is going to be your media.

Botanicare Cal Mag Plus (2-0-0) Mg1.2% Ca3.2% Fe.1% 1.0208 g/mL @10mL/Gal
N 54
P0
K0
Mg 32
Ca 86
Fe 2.7
Derived from: Calcium Nitrate, Magnesium Nitrate, Iron EDTA.

Botanicare Pure Blend Pro Bloom Hydro (2-3-5) Mg.5% Ca1%
4360g/3800mL = 1.147g/mL
@10mL/Gal
N 61
P 40
K 126
Mg 15
Ca 30
Derived from: Fish Meal, Composted Seabird Guano, Kelp, Rock Phosphate, Potassium Carbonate, Magnesium Carbonate, Calcium Carbonate. 0.15% Humic acid derived from leonardite.

 

[Snow Crash]

I guess its possible its a cal or a K issue, but it looks most like the pics from people with toxins off gassing (from tents or NGW hose). Id look and see what kind of different plastics are in both of the rooms.

Argh! I always forget that BS plastic is still floating around. I don't see it often, maybe once every 3 or 4 months, but there are definitely still people suffering from that. Given the... indeterminable cause due to peculiar symptoms I agree that this is something that needs to be addressed that hadn't been brought up in the conversation.

I will be glad to learn what the issue is when we pin the cause of these symptoms down so I'll know how to recognize it in the future.

Botanicare Pure Blend Pro Bloom Hydro (2-3-5) Mg.5% Ca1%
4360g/3800mL = 1.147g/mL
@10mL/Gal
N 61
P 40
K 126
Mg 15
Ca 30

Not to nitpick, but I'm not really digging how you are listing the Phosphorus and Potassium. I know, I know... On the labeling "P" is actually for the concentration of P2O5 (44% if I remember right) and "K" is actually for the concentration of K2O (83% I think) . You are listing the actual elemental ppm of P and K... but...

For the sake of the newer growers who might not know this tidbit (took me like 2 years to stumble upon the relevance) it might be better to be a bit more specific. When you list "P" you're not talking about P2O5 as many people interpret it. When talking about elemental phosphorus, defining it as such - as opposed to P2O5 - helps clarify the information. This will help a confused, new, grower from thinking they need to add a good deal more phosphorus to their PBP formula in reaction to a perceived low level (as I might have done in my youth). A problem for certain when the ratios are actually pretty much in line with your averaged Cannabis tissue elemental composition.

Anyway, good info, thanks for the work you're putting in.

 

[eyeswideopen]

Thank you both for the info. I hadn't thought about plastics at all. The hose is hydrofarm hose. I've used NGW at my place and not had any problems. He does have his veg in a cheap no name tent though. Also, there's no media, the plants grow in 2" net pots with neoprene collars, that's it.

So what are good and bad plastics, and how does off gasing work?

 

[eyeswideopen]

Just read about the bad plastics, that's crazy, never even occured to me. I don't think that' s my problem though after reading about it, because I have perfectly healthy plants right down the road and we split a 100' roll of hydrofarm hose. Could be the tent, but this is more rust spots than overall plant yellowing/crisping.

 

[treehugger]

Nute solution should never be mixed with a meter, It is entierly too inaccurate. meters are for monitoring solution not mixing it.

Perhaps you would like to talk more about your reasoning on this subject?

 

[desertsquirrel]

Perhaps you would like to talk more about your reasoning on this subject?

certainly...

First of all ppm meters do not measure ppms. They measure Ec and convert that number into ppms. So, this not only limits the number the ppm meter will read in (multiples of ec) but also leaves the conversion rate uncertain (different meters convert at different rates.) Also there is the calibration issue of meters (human error).

Furthermore, meters, ppm or otherwise measure total disolved solids in a solution and do not differentiate between usable and non-usable ones. thus your measuring dyes, preservatives, additives, fillers etc in addition to both the unavailable and available elements in your solution.

By contrast i can do an actual available ppm analysis in about 60 seconds and all i need is the bottle of nutes and a calculator. And the analysis is correct down to the last ppm.

 

[phenotyper]

desertsquirrel, I asked this question in your other thread, but how do you know the concentrations down to the last PPM by weight when there are other unlisted ingredients that don't make up the nutrient profile (dyes, etc)?

 

[Snow Crash]

desertsquirrel, I asked this question in your other thread, but how do you know the concentrations down to the last PPM by weight when there are other unlisted ingredients that don't make up the nutrient profile (dyes, etc)?

Simply put, you cannot. Agricultural labels only list what is guaranteed in the bottle. There will inevitably be other stuff in the mix.

Let me give you some examples:

You can calculate the value of Liquid Karma, and expect to read a certain level given the advertised nutrient values. When tested this product reads a 9 times higher EC than what can be predicted with a ppm calculation and .5 conversion. When 10ml in 1 gallon should read something like 0.025ec it actually reads closer to 0.31ec. That's a pretty big jump you cannot know just by reading a label.

Cal-Mag Plus reads 2.6 times higher
Bud Candy reads 7 times higher
Pro-tekt reads less than 1/2 what it should
CNS 17 Ripe reads 1/10 more than it should

Then you have to consider that your meter is (probably) using a NaCl solution. This means that the only elements that will read true on your meter are Sodium and Chloride. It is common to see the listed ingredients contained in the bottle not meshing with the listed elements. Usually regarding sulfur (when using sulfate salts).

What you want to take away from all this is that you need to find the EC that your plant responds to best. Use a calculator to predict your element ratios when mixing several products to ensure you're not imbalanced, but when it comes to measuring your solution and learning what works best... That becomes more of an experience thing. You will need to compare how your plants do at different levels and play with things over time. It takes more than 1 grow to dial in a plant just right. As long as you are working with the same nutrients then just compare your results and keep a good journal of what EC you are using. You can use this data to perfect your feeding schedules.

You'll never know exactly what is in your formula, they don't have to tell you, and even if they wanted to... the Ag industry controls what can be listed. Trust your brain. Not a label. Not a calculator. Not a meter. Keep the data and use your mind to sort that data smartly. It's all about figurative conceptualization based on the best info you can get yourself. The more information you collect the better.

 

[phenotyper]

I appreciate the detailed information, but I was posing the question as a way to question his methodology, which you corroborated as I suspected, as being flawed.