Two types of leaf damage... are they linked ?

Just as the title states, I have noticed two types of damage occurring on my leaves, and wondered whether they could be linked.



Pretty sure this is leaf minors, little shits... I know that they're protected by the membrane of the leave so spraying them is not that effective. They have 7 weeks in flower left to go, are there any long term solutions, or short term fixes, I'll take either right now...



It's these almost radioactive, yellow blobs that have confused me, I have seen a few suggestions in the sticky threads but these markings seem different somehow... surely they can't be linked to the leaf mining, right ?

Cheers

K

I don't think that's leaf miners. Looks more like Ca or P, which is most likely due to low pH. What's your pH now, or did it drop pretty low in the past? Looks like there's some heat stress as well in the first picture. What kinda light you using and how close is it? And where is the leaf from the first pic on the plant, towards the top I'm guessing?

dtl420 said:

I don't think that's leaf miners. Looks more like Ca or P, which is most likely due to low pH. What's your pH now, or did it drop pretty low in the past? Looks like there's some heat stress as well in the first picture. What kinda light you using and how close is it? And where is the leaf from the first pic on the plant, towards the top I'm guessing?

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I've had the pH ranging from 5.4 to 6.0 so that as it drifts up, the spectrum of nutrients can be taken up. I don't remember an instance where I have taken a lower measurement in all honesty. Temperatures are a constant 23C, previously went up to 25C. There are three fans for circulation, an intake at the floor and exhaust overhead. The lights are aircooled 600w lamps approximately 18" from the tops. Yep, that leaf in the first picture is from the top third of the plant. There are a few specs on the other plants, though this plant is one of the biggest and seemingly most afflicted (though one of equal size, same strain, isn't affected nearly near as much). RH is 50% constant.

Cheers

K

That seems a little close to the plant for HID. I have a 1000w cool tube with a super blue MH in it, and I have it 27in from the tops. You can use a point and shoot surface thermometer from your local hardware store to see what the temp of the canopy is. There is a big difference between the air temp and the temp of the leafs, especially with HID lighting.

What are you feeding, and how much? (per gal preferably, I don't know meteric)

I have surface (canopy) temperatures of 24C/25C (+3C from ambient, it's really well ventilated). The feed is the Canna Aqua range, they're on the first week of veg feed in flower cycle at 1.8EC (less 0.5EC of tap water to give 1.3EC). I've just raised the lights another 5 inches, I agree about the Ca deficiency, it looks so much like a bug attack !

It looks more like a leaf fungus than bugs to me. Bugs usually leave a whitish green mark, leaf miners leave a whitish green squiggly line. But you've got the RH in check, so I doubt it would be a leaf fungus as they thrive in humid conditions. Have you checked the calibration of your pH meter?

@Ablaze @OldMedUser or @Cold$moke any suggestions?

Yup, it's spot on both pH 4.0 and pH 7.0 when tested in calibration fluids, ironically it is a $5 pH tester and it was the $45 Essentials tester I recently bought that was throwing up incorrect values after calibration. The leaf damage does look extremely similar to the images results on the internet when searching for "Ca deficiency". I won't jump yet, but looks like I need some cal / mag from the local hydroponics store...

Kieron90 said:

Yup, it's spot on both pH 4.0 and pH 7.0 when tested in calibration fluids, ironically it is a $5 pH tester and it was the $45 Essentials tester I recently bought that was throwing up incorrect values after calibration. The leaf damage does look extremely similar to the images results on the internet when searching for "Ca deficiency". I won't jump yet, but looks like I need some cal / mag from the local hydroponics store...

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But you're using tap water, correct?

Yep, this is what I don't understand, there should be enough in the water, it doesn't have an RO filter on it etc...

From those pics I see a calmag deficiency. The outer leaf seems to indicate a possible heat issue. But could stem from a couple things.

And I'm not sure how you feed but that yellow radioactive spot looks like water with liquid nutrients mix in burnt it, by splashing on it, if you feed that way.

Definitely light too close

And his water could have calmag in it sufficient for other strains, my water is like this, but other strains I have to add another 5 ml per gallon of calmag, usually during veg only

Ah... as for watering, 2.5 gallon buckets at a time into the reservoir, there might be some slight splashing occurring

That'll be 12ml per 10L for over here in the UK in that case, they've just come out of veg actually and are in the first week of their flowering light, though still on veg nutrients as per the canna guidelines.

Seeing as though I am not showing signs of a magnesium deficiency, couldn't I just add calcium, though I think I may have read somewhere that calcium and magnesium should be added together, I just don't want to add unnecessary things to the nutrient solution.

Not necessarily added together but they can lock each other out if not in the proper ratios .

Too much mag makes a cal deficiency
Too much cal makes a mag deficiency

Typical bitch, not happy with what she gets

What are you feeding it again?

And you can let your ph drit to about 6.3 To 6.5 before adjusting imo.

They're on Canna Aqua nutes, they've had their last feed of Rhizotonic for their roots now they're in flower, but they'll continue to get CannaZYME to keep the roots in good condition. I could certainly let it drift higher, as I am aware that calcium is absorbed at higher pH levels, wouldn't 6.3 - 6.5 be too high though, even with it being hydroponic...

This one is easy...

....more cal mag please.

Now it's up to you to determine if it's the pH locking it out, or if it's just deficient. I'm leaning towards deficient, but you can let pH drift up to 6.3.


Best of luck.
Peace

Look up ph nutrient absorption rates.

It will show you how different nutrient and macro nutrients are absorbed at different ph ranges better than i can explain.

Whoops i reread and saw you know that

Most people feel if their system ph rises while ec falls you are good because the plant is actively absorbing the nutrients.

Is ther going to be problems if you let it drift to 6.5 no not in my opinion unless you leave it there for weeks

Will it be optimal to the tenth, meh
does it have to be nope .

this is also very strain dependant as well some like more acid some like more alkaline whithin reason.

Ive grown plants in straight un phed water (a good way to keep a plant slow growing ) if your away. For weeks lol

I'm hoping you guys might be able to help with this one. I bought some Canna CalMag today and before adding it to the tanks want to be sure. The directions on the website for the CalMag state this :

Soft water has an EC of below 0.4, by raising it with Canna Calmag Agent all Canna products can work to the optimum levels.

Normal water has an EC level between 0.4 and 0.7. It contains calcium, magnesium and bicarbonate to stabilise the pH. All Canna products are designed to work best with this type of water.

Hard water ( EC > 0.8 ) contains more calcium and magnesium than the plant can handle. When you’re growing plants, the best way to treat this kind of water is to use a reverse osmosis filter and then use Canna Calmag Agent to raise your EC level to 0.4.

I have water with an EC of 0.5 which means I fall into the normal water category, and shouldn't be having problems with calcium deficiencies (unless despite the EC there are low calcium deposits in the water), I have double checked my pH with a few meters and it's definitely not inhibiting the uptake of calcium.

I run two Wilma systems, and have noticed that both the indica and sativa phenotypes of the Critical + 2.0 that I am running are both exhibiting the symptoms of calcium deficiencies (brown leaf spot etc...) which lends itself to the idea that it is the water, however the plants are afflicted to different degrees, some minor, some a little more, again this could simply be genetics.

That's my current take on the issue, and so given the guidelines per litre from Canna, to "raise soft water levels to an EC of 0.4", it is lost on me, I have an EC of 0.5 and so I can't use their scale which is obviously for people who have the low EC water and lack of calcium, where I have higher EC and still a lack of calcium (going to get a water analysis done so I know where I stand).

I know @Cold$moke gave me some suggestions about the amount to use, are there any parameters that I would need to look at to dial this in...

A further issue is that only one plant in one system has is pretty bad compared to the others, are there consequences of adding these additives to their nutrient base ?

Save these images for later reference. They're what @Cold$moke was talking about.

Ah that's handy, in the event I have to play detective. I've increased pH to 6.0 and in the future will let it ride from 5.8 to 6.3 and see what happens. They've grown fast so likely the low pH didn't allow them to take up as much calcium as they wanted...

Cheers

K