42 Day Old Plants have rust spots and other symptoms. Advice?

[Yoop906]

Greetings!
This is my 3rd AF grow. 3 Bluetooth Autos and 3 Amnesia Haze Autos. LST.
- 4x4 tent with five 300w LED's (actual 70w draw). It's a mixture of cheap LED fixtures. Run 24 hrs a day. About 18" above canopy.
- Pro-Mix Ultimate Organic soil from the local Menards. I added some extra perlite.
- 3 gal grow bags
- Dyna-Gro nutes - Foilage Pro, Bloom and Mag Pro.
- Great White and Pro Tekt supplements.
- Room temp at canopy stays solid 74-78 deg. Humidity is at 51% varies only 2-3 points. Excellent air exchange with a 6" exhaust fan. LED lights are always on.
- I have well water that is 450ppm. I have an RO system that drops it to 75ppm. However, I water with a 50/50 blend of RO and well water. My well water will scale up a coffee maker in no time - very high calcium? I screwed up with my last grow by using straight RO water. I know what I did wrong but it still scares the shit outta me to use it straight up, even with the proper supplements. So my blended water starts at 150- 225 depending how accurate I measure.
- I have been watering each plant as needed. I use the "lift the pot method" to determine when to water. Each plant will vary some but will only get watered when the pot is light enough.
- I do alternate waterings. PH'ed blended water with 5ml/1tsp Cal-Mag Plus and Great White. Then next watering w/nutes. When I water nutes I am using 2.5ml Dyna-Gro Bloom, 2.5ml Mag Pro, 1.25ml Pro Tekt, 1/2tsp blackstrap molasses and 5ml/1tsp Cal Mag Plus - that adds up to usually around 600-650 ppm.
- I keep my water PH at 6.3. I always water to at least 20% runoff as that is what a gallon will do per plant normally. I religiously check my runoff PH and it is generally around 6.5.

I think that should be enough info - if I have missed something please let me know.

I have attached pictures of a few plants that seem to be having issues within the last 2-3 days. They have developed rust spots on leaves mostly near the top of the plants. But you will also see that even lower leaves have spots on them. Growth over the last 2-3 days may have slowed also. However water intake hasn't slowed.

These pics are taken with 2 of the full spectrum 300w LED's turned on. It's not the burple light it's more white/pinkish and seems to make the spots and light colors stand out more in the pic so I left them on.

PH off or fluctuations? I have monitored runoff and is around 6.5 ish.

Magnesium deficiency?

Calcium deficiency?

Deficiencies due to root lockout? But why?

I should be due to water tomorrow. Time for PHed water and Great White.

ANY AND ALL ADVICE IS APPRECIATED!

peace.

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[namvet25]

Thanks for the detailed info.It looks like phosphorous def caused by lock out so I would flush with plain ph water,flush with at least 2gal than feed her with 5ml per gal of bloom nutes and 1tsp cal/mag at every watering.I would also suggest running 18/6 on your lights to give them a rest period like they would get when growing outside.You really don't need to add great white that much at this point because roots should be well established at this stage.

 

[Yoop906]

Thank you!

Per your advice I will flush the plants with at least 2 gal pH'ed water and check runoff pH and ppm. Then feed with 5ml/gal Bloom and 1tsp cal/mag. When you say "at every watering" do you mean for me to stay on my alternating water/feed schedule and use cal/mag when I do the feed only or do you mean use cal/mag when I water in addition to when I feed? Or are you suggesting that I do not water in between feedings? I just want to be super clear on that.

I have spent some time researching phosphorus deficiency and it seems that it is common when using LED lights that are too intense. Last night I turned off two 300w LED lights leaving just three 300w LED's on - I ran out of head room so I could not just raise them higher. I am currently at about 20-24" above the top of the canopy. The plants looked much better this morning - no drooping leaves anywhere (had a few before) and they just looked happier. I will be investing in a PAR meter to get a good reading of the LED light intensity.

Also a somewhat related question or two that I hope you can shed some light on for me.......I have read that I should be at about 900ppm when feeding. Do you agree? If I use strictly RO water that is at 75ppm can I then make up that 825ppm (to reach 900ppm) with Bloom even if that puts me above 5ml/gal of Bloom? Should I not use the Dyna-Gro Mag Pro at all?

Thank you for all the help!!!

Thanks for the detailed info.It looks like phosphorous def caused by lock out so I would flush with plain ph water,flush with at least 2gal than feed her with 5ml per gal of bloom nutes and 1tsp cal/mag at every watering.I would also suggest running 18/6 on your lights to give them a rest period like they would get when growing outside.You really don't need to add great white that much at this point because roots should be well established at this stage.

 

[namvet25]

Unless your doing a hydro grow there is no need to worry about ppm so just ph your intake water at 6.5 and you should be ok.I am also using Dyna-Grow and that is the dosage that I use.I feed every other watering but it's so dry in my grow room that i'm amost watering every other day.What does mag-pro have in it? Just feed every other watering if your wartering more than twice a week or feed every water if you go farther between watering.

 

[Yoop906]

This is from the Dyna-Gro site:

Total Nitrogen (N) ……. 2.0%
Ammoniacal (NH4) …… 1.1%
Nitrate (NO3) …………. 0.9%
Phosphorus (P2O5) ….. 15.0%
Potassium (K2O) ……… 4.0%
Magnesium (Mg) …….. 2.0%
Sulfur (S) ……………… 1.5%
"Mag-Pro® 2-15-4 is a concentrated blossom booster designed to help plants initiate flowering and develop large, vibrant, aromatic blooms. Mag-Pro® provides high levels of phosphorus, magnesium, and sulfur, to pack on enormous weight during the flowering cycle, while simultaneously enhancing color, resin production, fragrance and flavor in your valuable flowers. The nutrients in Mag-Pro® are immediately available, giving your plants the ability to access the nutrients they need at the critical times of flower formation to ensure massive growth and enhanced flavor and aroma through increased production of essential oils, terpenes, and flavanoids. Growers using reverse osmosis, rain or deionized water will benefit from the addition of Mag-Pro®. Use Mag-Pro® instead of a calcium/magnesium supplement because there is ample calcium in all complete Dyna-Gro™ nutrient formulas and those supplements do not have the sulfur, phosphorus and potassium found in Mag-Pro®. Mag-Pro® is THE blossom booster for growers looking to maximize the beauty and value of their crop."

I had not noticed this before:
"Use Mag-Pro® instead of a calcium/magnesium supplement because there is ample calcium in all complete Dyna-Gro™ nutrient formulas and those supplements do not have the sulfur, phosphorus and potassium found in Mag-Pro®."
This appears to mean that no cal/mag is needed period, when using Dyna-Gro nutes. Or did I miss something? 2 years ago when I decided to use Dyna-Gro it was after a lot of research. What sold me was the macro and micro mineral elements in the nutes. Not having to use cal/mag is pretty cool too. I can't believe I didn't know this........maybe I did, lol (old, bad memory).

I'd like to stay with using the MagPro and Bloom to the finish on these plants and then maybe switch up on my next grow - unless of course I shouldn't? If using both should I use no more than 5ml combined?

 

[Waira]

.... mate, I think there's a snowball effect happening with certain nute elements' uptake caused by all the Ca, Mg and water hardness, a cumulative thing,... excess of these wilart to intfere with each other's uptake, (competitive deal, not necessarily pH related),.... also, some nute elements metabolism is adversely affected by this; point is, even if the nutes are there, they aren't getting taken in and utilized,... I really need an in-pot pH taken, as run-off is not an accurate measure of this,.. even the "improved" method and calculation we have here (highlighted section above this) isn't that good,... nutes, adjusted water, all will skew true results because of the pH altering affects they have on the soil's current pH,... That said, with r-o coming out at 6.5, it does hint that it's not badly off in there,.. if came out in the 5's, or near 7, then there'd be a certain problem... So with the assumption that in-pot pH is more or less OK, this cation overload is the more likely possibility here,... Look into getting the Accurate 8 soil pH probe, nice unit for the price, and gives you that critical in-pot pH right in the root zone!
Your water blend, final ppm is about 150-225? I ask because a 50/50 blend of 450 and 75 will not end up in this range,... I'll ask just to be sure: are the pH meters and TDS calibrated recently? pH is more likely to drift off, TDS holds much better.... And the RO water, is 75ppm? That's very high, a possible overloaded membrane might be behind that..... Straight RO water (under 10ppm) isn't a biggie, you just need to add Ca-Mg to it, so it get some pH buffering capacity to it... with no buffering minerals in there (CaCO3), even small inputs can cause wild pH swings,.. Another note: taking the pH of RO/Di water is largely pointless because of the way the meters work with ions to determine pH,....
I'd say run with you straight RO if it 75 ppm,.. has it always produced this with your well water? ...could be it's just not beefy enough to handle that kind of ppm's for long,...
.... I see you raised the lights, which was needed,.. they were too close previously, a possible contributing factor as well,...
... Did you flush yet? I'm of two minds on that,.. and if you do, it has to be at least 2-3x the pot volume of low ppm water,... final pour should include weak nute dose,...
... yeah, you always have to keep a good tally on your collective nute/supp' inputs,... Ca-Mg is often a "sneaky" source of N, P... You have the Botanicare CA-Mg Plus?-- if so that's loaded with other goodies,...

 

[Yoop906]

My RO system is a generic $65 5-6 stage (forget which). I have had it running for maybe 4-5 months and it has always produced RO water at 75ppm. That didn't seem right to me either but I was just happy to get it down in that range. I will double check my ppm numbers on my well water, RO water and 50/50 blend of each - I just calibrated my 2 pH meters a few days ago, have not calibrated the TDS meters but they both read the same values.

At the top of my "buy" list is a PAR meter for LED's and a soil fertility meter. Soon I hope.

After raising my lights and doing a feeding with 5ml/gal Dyna-Gro Bloom and ProTekt they seem to be back to normal growth and look happy as hell. I was going to flush first but said screw it and gambled on raising the lights and doing a feed without adding any cal-mag this time. I will be eliminating cal-mag from their diet as the Dyna-Gro nutes all have cal-mag in them. I have a PTZ camera in my tent that has preset positions I can move to so I am able to get nice time lapse pics when needed and overnight the pics showed excellent growth. Still have discolored leaves but new growth is fine.

Cal-mag overdosing in combination with too high of intensity LED's causing a phosphorus deficiency..........Yes/No/Maybe?
It seemed that I could almost see that the discolored leaves were in the areas where my lights overlapped.....would that make sense? Maybe the correct way to ask that would be; Will phosphorus deficiencies caused by too high of intensity LED's show only on areas where the intense light hits or will it show in any or all parts of a plant?

Thanks for all the help everyone!

ETA: My runoff tested at 6.5-6.7 pH on every plant. Runoff was a very consistent 400ppm with 2 of the plants reading about 600ppm. These 2 plants were the last to sprout and have always been much smaller than the others.