What the hell is this? Is this a cal mag deficiency? HELP! It's spreading upwards

I saw a pic my friend showed me and it looked like a calcium magnesium deficiency on steroids... I've done a little reading on the net and would like to know 1.) what this is, and 2.) how do I get rid of it?

The local guy at my nursery just tried to get me to buy a ppm or ph reader at $70 each... then said he didn't know how I could fix the problem. What to do?!?!?! Thanks in advance!


edit: I'm on week 2 of flowering

These pics were taken 5 days ago.

"What the hell" by Jon the Baptist?

What are you feeding? Are you feeding? Plant age? Medium? Lights? pH of your water?

most plants dont get a calmag deficiency till growth really accelerates. looks to me like a nitrogen deficiency and its making its way up the plant. u could have a ph issue (under 6 over7) that is locking out the nitrogen. so the guy was pointing u in the right direction but remember these guys get a ton of questions and before they will just share all their hard earned knowledge they need u to purchase essential tools to do this hobby right. You not having a pph meter or a way to test ph is gonna hurt u in the long run. ph is essential to complete nutrient uptake. ideally u wanna be 6.5

I am running 450watts under HPS, just turned it up to 600watts last night. I started feeding it Fox Farms Tiger Bloom (just one feeding, then I stopped) but am now using regular tap water. I used a liquid pH test and it seems that the pH of the water is between 7.0-8.0 (but not exceeding 8.0 at all). Using aerolite soil with earthworm castings. Plants will be 8 weeks old on the 20th, and will begin their 3rd week in flowering on this upcoming Monday.

This guy definitely wasn't helpful, from not knowing the pH of his store-made soil to not knowing what I needed to attach my CFL & CFL base plate to a surge protector so I could get the lights running. I will definitely buy a pH soil reader and ppm meter online for cheaper.

ok u answered ur own question. try a few waterings of %50 grow nutes at a ph of 6-6.5 and get ur soil ph down. if u are feeding it ph water of more than 7 then ur nitrogen is locked out....like i said ur water/feed should be at 6.5. every single time. 8 is WAY WAY WAY to high my man.

Get some dolomite lime from the hardware/garden store. It's cheap. transplant them into bigger pots and give each one a couple tablespoons of the dolomite lime. You are having PH issues and the lime will cure the PH problem. Give them fertilizer every time you water. Like a half teaspoon per gallon.

That's all you need to do.

from the looks of the pics, the problem can stem from letting your soil dry out too long. when this happens ppms shoot to the roof and ph drops. flush until ph and ppms are back into range.

Foliar feed with nitrogen nutes, After The lights are off! MORE NITRO

looks like the boys from roll itup saved the day once again. def looks like a nitrogen deficiency to me.

i agree ph way to high i ph with lemon juice because i grow organic . and to be safe add i tea spoon per gallon cal mag and do this once now, once in couple weeks that should sort out the magnesium deficincey .better safe than sorry

Thanks for all the responses. I will try the easiest/cheapest solution which will hopefully be watering more frequently. I do admit I don't water that much as I always wanted to make sure I never overwater, as that can be more harmful than underwatering (or so I've read). If plain water, no nutes, don't remedy the situation I'll be having a ph meter coming next week as I will order one tonight. My only question is, will this suffice?:

http://www.mrocenter.com/general-tools-glmm300?utm_source=GoogleShopping&utm_medium=ComparisonShopping&utm_campaign=GENERALTOOLS-GLMM300

I'm really not sure if the water is 7 or 8, as the shade of green between those two numbers are hard to distinguish after testing. I foliar feed with a spray bottle (no nutes) every day or so, so I don't water that much (maybe every 3 days).

GreenthumbSucker, I can't repot and transplant again. I've got 5 gallon pots, one 3 gallon pot, and will run out of space with anything bigger. Hopefully this will not be too much of a problem.

as a temp estimate for yo i ph with lemon juice 5ml per litre takes water from ph 8 to 6.5. so lets say your water is 7 if you used 5ml lemon juice would take it to 5.5 . i rough it and ph water alitlle until you get a ph tester .

Wouldn't 5.5 be to low then? Or is a little low better then a little high

JonTheBaptist said:

Wouldn't 5.5 be to low then? Or is a little low better then a little high

Click to expand...

5.5 will not immediately drop the ph and may actually help if urs is to high likewe think. foilar feeding plain water is pointless as there is nothing for tthem to feed on lol so its more like a shower. foilar spray with sum nitrogen and know in advance that the damaged leaves will most likely not recover so make ur new growth the focus of ur efforts.

Dont worry about lemon juice and cheap strips, get a digital ph pen with adjusters and make sure everything that goes in the soil is 6.5. The high ph is csusing all the problems here and just watering more will make things worse.

Mag... green veins with yellow leaves is one of a few signs.
Could be Potassium thats another sign
Since it sounds like you are not watering enough for Coco


Check out this forum thread this will tell you what you are looking at its really good
https://www.rollitup.org/marijuana-plant-problems/488004-guide-nutrient-deficiency-toxicity.html

Yep.. N wouldn't leave the veins green, looks like Mg lockout from pH or salt buildup from under watering. Your leaves look too alive for it to be Nitrogen.

Ok well I fired them up earlier and things escalated rather quickly... I've included todays pics as well as pics of what I was recommended to buy at my garden shop

I will read that thread tonight. So it seems that its a toss-up between nitrogen, mag, and possibly potassium deficiencies?

I just fed them the first dose of flora kleen as instructed to see if I can flush out the soil. I will be getting my pH meter in the mail next week to figure out exactly what my levels are.

As you can see two of the four bottom most leaves are now completely yellow.