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Magnesium Deficiency???

NeneNZ

NeneNZ

New member
Hi folks , I think this discolouration is due to magnesium deficiency.
what do you think ?
we have just started implementing EC readings and making adjustments for the first time .
never had an issue like this before now
by the time the "food" is ready I have diluted 1 x 20 litre bucket into 2 x 20 Lt buckets to get the so called correct reading
doesn't seem to be going too well
growing in 70% coco/ 30% perlite.
auto flowering indoors .

is the ppm or ec adjustment really necessary if I'm managing the PH well ?

our water is not hard but does have fluoride & chlorine added :mad:
 

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It looks like a pH problem to me. In coco, the ideal is between 5.5-6.5 pH. EC measures how much "stuff" is in the water, but not the pH. PH being too high or too low is the most common cause of nutrient deficiencies.

What's the pH of the nutrient water right before you give it to the plants? What's the pH of the runoff water?

I know there's been many times where I mix the nutrients and adjust the pH to the perfect range, and then I see a nutrient deficiency, and check the pH of the runoff water and realize it's much higher or lower than what I'm putting in. It really helped when I got a big 100ml syringe off Amazon so I could easily collect the runoff. It would work perfect with those trays, so you don't have to move the plants to collect the runoff water.

So for example, if the nutrient water going in at 6 pH and coming out at 5.5 pH, you know the ph is "low" at the roots, because it's causing the water pH to drop. So in that case, you'd water the plants with 6.5 pH for a while until it normalized to the right pH. If it's coming out high, you'd water on the lower end (5.5 pH) until it starts coming out normal.

Overall it doesn't looks too bad. You seem to be keeping a close eye on your plants. Great work!
 
Hello NeneNZ I've been where you are. If the PH is good why bother with EC, right? EC is important. You're correct though, diluting the final the solution does lower the overall strength, but it does not change the ratio (the N-P-K balance) of the nutrients. That's the important part. If you want to dilute your solution less at the end, start with a weaker dose of nutrients.

Growing in coco you must know the starting EC of the water you use for your plants before you add any nutrients. Otherwise you are aiming at a moving target. What nutrients are you using? You want your starting EC to be .4 with coco. If your tap water is .4 you are golden. If it is less than that supplement with cal/mag to bring it up to .4. stir the water well, add nutrients one at a time, stirring well in between. Once everything is added let it rest 30 minutes or so to help stabilize the solution. Then check the EC. If you supplement with cal/mag be sure to add that to the water you will use to dilute the nutrient solution. Once you get the EC you want, adjust the PH. I have an EC schedule for each stage of growth. Is that what you do? I start at .6 and gradually increase that to a max of 2.0-2.1 during peak flower for photos, a little less at the top end for autos.

I would not worry about the chlorine and flouride, if you need to treat your tap water use a dechlorinator for aquariums, works like a champ. Add that first then everything else.

BTW, I hope you don't mind me asking, is that NZ New Zeeland?
 
Thankyou golfnrl.

Yes, NZ is New Zealand .

This EC is very new to me as I could never find any info on how to adjust the EC ..
So I thought I must just dilute with tap water .

we're using Nutrifield Coco A&B , Vegignitor, And Flairform CMX [cal mag]
Plus Nutrifield PK Heavy for flowering cycle

In tap water :
The EC reads 0102 or less
Ppm reads 0051 or less
Seems to depend on our water treatments.

Would you read those ppm results as .5 ?
Or EC results at .1 ?

Yes, there's a schedule for the feeding .. recommended EC starts at week 1- 1.1, week 2 - 1.3 , week 3 & 4 - 1.5
Then 1.8 up to 2.2 (weeks 1 - 5 flowering cycle) the back down to 1.5

How much run off do you allow?

We're using airpots and sometimes fabric bags .. probably have too much runoff which we're changing up .
We have high humidity here also ... tricksy to get the watering in the goldilocks range to be honest.

also... the EC Pen is a cheapo ($20)... unlike the pH pen ($180)

Do you think we should invest in a better EC pen ?

Again .. thank you very much for your assistance
 
Thanks MeowMeow ,

Yes, I do the processes you've mentioned regarding pH management .
The issues have started with trying to get EC sorted .
It seems to be the usual thing .. until you've got it ..you haven't got it.... and we haven't got it ..yet.

Thanks , we do watch them like babes . But these plants are like no others .. looking prone to problems arising 😔
 
Cool. I'm in Oklahoma. Middle of the USA.

It's hard to say what those meter readings may be without knowing which scale your EC pen uses either the 500 or 700 scale. I'd guess that the EC of .1 is close.

Those EC numbers look pretty normal. If you can, stick with them.

My system does not have any runoff. I grow in the autopot system. It uses a reservoir and is a bottom feeding wicking type of feed system. Works off of gravity, no moving parts.

Yep, high RH is a PITA here as well.

If I might suggest so, yes, invest in a quality EC pen. I use a BlueLab EC pen and PH pen. I also use their PH controller for the reservoir. I'm sure there are other reliable brands.
 
Awesome , my husband has been to Oklahoma :laugh:

the cheapie EC pen has sold out on temu ..no info available .

we have a Bluelab pH pen and will buy a Bluelab EC pen & calibration solution tomorrow.
I'm sure I will figure out what's what reading the info in the pack

if as you say , you think the EC on our tap water is .1 , then we need to increase the calmag alot .. ?

I have seen those pots you're talking about ... mmm we may consider them .

yeah high RH is a total PITA ... that's where the autopots would be super handy

.
 
Without knowing for sure what the actual EC is in your starting tap water I'd switch gears and use 1/4 or less of whatever the recommended dose of cal/mag is. I use GH cal/mag. 2 ml per 10 L will raise my starting EC 2 points. The goldy locks zone is .4 to start. The EC pen was simple to set up if I remember right, all I had to do was turn it on, LOL. It reads almost instantaneous.

I hope the Oklahoma experience was OK, :).
 
Ahhhh yes he says it was definitely memorable..in a good way hahahaha.

GH cal/mag ?

Ooooo k.i.s.s. principle is my fave lol
Turn it on and in biz just like that

I'll be so relieved to have a handle on this conundrum

GOLDILOCKS
Yup .4

Thanks so very much 😊
My gals and I appreciate it

OK.. those leaves have got darker veins than they ought .
But I believe they'll come right when we stop aiming at that moving target
🌱
 
I saw the slightly darker veins and minor mottling, but I put it down to growing pains.

You're in coco so make sure your feeding at a nice wide range. The higher end is where she'll get her Mag.

You will need to cal/mag suppliment & if you're not youll likely run into strife. I typically go every second feed. At that stage Id be fertigating probably twice a day.
 
GH Cal/Mag General Hydroponics is the brand. Sorry for the confusion. I laughed at goldilocks. I really can spell, lol!

Glad the OK experience is memorable in a good way. I'd like to make it to NZ and that part of the world some day.
 
Aha ..a brand we don't see here .. the Flairform is a good cal mag .

some day .. one day .. ye ol bucket list .

Well today's the day for an EC pen that's honest and hopefully easy as you say :silly:

do you mind if i keep in touch with our ec progress ?
 
Absolutely. Post on this thread and we'll be notified. Or send a DM, either way I'm happy to help. There will be others that chime in as well. BTW, I almost asked about the pen but didn't want to intrude.
 
Okidoki golfnrl
thanks for staying in our loop

we bought a Bluelab EC pen monday only to return it next day as it refused to turn on ... anywho we now have a perfectly functioning pen 😀
after contacting Bluelab support we have ascertained that the reading on our tap water is below 0.1 (see the image attached) PPM 500
infact it reads at 0.0
apparently this is very common in NZ

We're in week 3 veg cycle
so I figure the EC to head for is 1.5 after all the nutes have been added and sat for 30 mins

i'm unsure about the cal mag situation as the reading is so low .
should we adding more than the 1ml per liter as suggested on the bottle ?
OR add calmag to the diluting water ... ? But how much to add to it ?
I just thought too ... should I just add the cal mag to the diluting solution and not to the nutrient solution ?
 

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I just knew that something would go wrong with the pen, lol. But I'm glad you got it working.

Just make sure your starting water is .4 EC by adding Cal/Mag to bring it up from the .0 - .1 to .4 That's the starting point. You will not need to add any additional cal/mag. Then add your nutrients. Set up your dilution water the same way, cal/mag only to .4 EC. You may have to experiment a little with the amount to add. It won't take a lot. I use .25 ML/L for 10 L of water. I'm guessing your water will test out similarly.

Once you have your nutrients added check the EC and dilute to your target number. Then PH the final solution. That process allows your coco to absorb the cal/mag that you add to your tap water. The coco absorbs cal/mag before the roots of your plants do. Your plants will have the full benefit of your nutrients without the coco robbing the solution first.
 
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Yeah I know right ? ! Always the tricksy pens ..tenacity and determination to get this job done properly helps ... and your invaluable assistance is amazing ! Thank You 😊

I trolled all over the Web including gwe and found absolutely nothing helpful about actually getting it right .
very frustrating indeed ..
it's " you don't know what you didn't know , until you know "

your explanation has boosted my understanding to do it right .. and a lovely K.I.S.S. principle to follow

wow that info about coco snuffling up the cal mag before the roots can have at it was enlightening !

I think I'll be zooming along now .. the gals 🪴 and I thank you ... I'll let you know how we do
 
I will drop a pic ... yesterday the whole process was simply easy as thanks to you
you will have to let me know if you do come to NZ ... we can show our gratitude in a green way 😉
 
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