Help Wanted - Is this ph fluctuation, cal-mag def, or something else?

Bag seed under 250W HPS, FFOF in a 3 gal smart pot. Supplemented with 1/8-1/4 dosages of Dyna-Gro Bloom and Cal-Mag.

Known Stress Issue:

No current exhaust system, tent is very hot and this plant grew crazy tall for it's starting size. She reached a little too close to the lights but her branches are so stiff LST isn't an option at this point, should be getting an exhaust in the next week. The light is pulled up as high as I can get it, I'm hoping the exhaust will at least be able to relieve the plant of some heat stress.

What I've done so far:

I've added more Cal-Mag to her feedings (3ml per gallon of tap water used).I've also top dressed the soil with some dolomite lime because I was using ph down in the earlier feeding mixes and I think maybe I threw the ph of the soil off. I read that dolomite lime has a ph of 7 and can be used to correct ph issues.

Any comments or suggestions are welcome, criticisms too if you have them. Sadly there is not much I can do though about my light or the plants position.

Please post a whole plant photo. What are your temps and humidity precisely if you know? What type of light and how far away?

MeJuana said:

Please post a whole plant photo. What are your temps and humidity precisely if you know? What type of light and how far away?

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Temps would be in the high 80's with humidity hanging around 40.

250W HPS if you read the OP and the light can't be no more than about a foot away. It's in an open wing reflector and like I said this plant is heat stressed because one I do not have a proper way to vent my tent and two the plant grew well beyond what she was intended too and now LST is not an option due to stiff stems.

Cal mag and pH

What is your media?

Afgan King said:

What is your media?

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Fox Farms Ocean Forest, as abbreviated in my OP.

Ya ID say pH and Cal mag what do you pH your water to? Should be 5.9-6.1

Afgan King said:

Ya ID say pH and Cal mag what do you pH your water to? Should be 5.9-6.1

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Isn't that really low for soil? Ocean Forest is an organic soil blend, it's PH is already between 6.3-6.8 according to the packaging, I think I threw it off by adding PH down to my water in the first place. I was Ph'ing my water to around 6.5.

I feed at 5.9 during veg 6.1 during flower then drop to 5.5 for flush. I used to use that same soil I use coco now but anything between 5.5 and 6.5 shouldn't really hurt anything outside of those parameters is disaster. If you wanna feed at 6.5 be my guest I was just saying what I do and have done here's my grow now

Heat and humidity you already identified as a problem and this can be the problems with nutrient uptake also I actually don't have experience growing in such hot conditions without supplementing co2 but I will go through this anyway. 6.5 pH is perfect and you are supposed to be setting pH with your type of grow. The dolomite top dressing was a bad idea but it will be ok just keep setting your pH to 6.5 and she will recover from the pH problem. Also I think you are watering too frequently but it could also just be heat stress. If you don't full understand how dry a planter should get do google searches and even youtube to learn. Additionally it almost looks like you have an N toxicity with leaf tip burn but that wouldn't jive with what you said you're feeding them. If I am having a Calcium issue I might use 10ml per gallon Cal Mag Plus only every other watering always setting pH the same then back to 5ml per gallon with my feeding. But that's only with RO water as it is possible if you're using tap water that there's stuff in it including Nitrogen depending where you live but certainly could be knocking your Ca out. So it might be good to buy that machine water in front of stores to solve your issues. Oh and back the lights up if you are noticing damage only on the top that you don't see on the bottom, hotter means the light can't be as close.

Edit: By the way Dynagro does have everything in one bottle although I use it only for veg never for bloom when I use Dynagro veg I don't use Cal Mag

You can look at those leaves and not see the cal mag deficiency? It's clearly there

Looks like cal mag toxicity

It is heat damage.

dabbindylan said:

Looks like cal mag toxicity

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this seems more accurate to the point that the toxicity locks out other nutrients like P, I'm not sure but seems you may have some reddish striping main/leaf stems, which may confirm a lockout of P. PH is usually is a dark purple striping on the main stem. I'm assuming the 7-7-7 is enough food. The clawing also looks like a N toxicity which also happens with botanicare calmag?. But with temps in the high 80s it's more than likely causing the problems.

anyone that says calmag toxicity is just guessing.

I have this same issue though my ventilation is there. My Temps are around 75. I Ph my water to 6.3. And i feed with general hydroponics nutes and 5 ml per gallon of cal mag with a pinch of Epsom salts. My leaves have dark purple stems and blotches, like yours. I think that I may be over thinking it. Why all the additives when soil with amenities should be enough. I can't seem to correct my issue no matter what.