Mag Def?... Nute Burn??

[I2KanGrow]

Here's some pics of my Northern Light - about a month into reveg. I've noticed some brown on the edges/tips of the "old growth" leaves. This plant has recently been repotted into fresh Promix/Vermiculite/Perlite (2/1/1) - with added bone meal (2 tblsp/gal), blood meal (1 tblsp/gal), dolomite lime (2 tblsp/gal), and garden gypsum (2 tblsp/gal).

H2O pH is at 6.4, and I did add chem ferts @ half-strength "for indoor plants", 1/4 Teaspoon/gal. - DynaGro Grow, in the last watering. (refer to the image below for analysis of these ferts)


Whilst this isn't looking too serious yet, I'm wondering if I should try to "nip
this in the bud", so to speak?

Looking at MyNameStitch's excellent problems tutorial - I'm figuring either Mag def or nute burn - Opinions????





P.S. - I had real issues with what I believe to be nute burn before harvesting this girl... I'd really like to get this under control before it looks like this!


As always - Thanks in advance!!

 

[Brian1975]

6.4 is your run-off PH??

 

[VanGrow]

your ph might have shifted with the new promix ....... and promix is ph balanced with lime out of the bag ....you gotta check the ph of your run off

 

[I2KanGrow]

Doh! Didn't check run-off pH, I'll do that on next watering, and get back to you guys - thanks for the fast replies.

So, are you guys thinking it's pH-related??

 

[MTF-Sandman]

Looks like you're feeding them too much N and not enough P & K...could be PH related tho.

 

[Blackvelvet]

Cal mag overload!

Cal mag overload!

This plant has recently been repotted into fresh Promix/Vermiculite/Perlite (2/1/1) - with added bone meal (2 tblsp/gal), blood meal (1 tblsp/gal), dolomite lime (2 tblsp/gal), and garden gypsum (2 tblsp/gal).

H2O pH is at 6.4, and I did add chem ferts @ half-strength "for indoor plants", 1/4 Teaspoon/gal. - DynaGro Grow, in the last watering.

Promix has lime already added. Then you added 2 tablespoons dol. lime. This is alot!!! Gypsum rate is 3/4 teaspoon per gallon not 2 tablespoons. Then you added dynagrow with calcium and magnesium. Cal mag overload. I bet that "burn" is potassium deficiency.

Solution: Take the plant out of the pot. Get as much of the new soil mix off the roots as possible. I might take a hose and wash the rootball. Repot the plant with promix and perlite with no vermiculite. Add no extra dol. lime since your liquid fert has cal mag. Do add the gypsum for beneficial sulfur but at 3/4 teaspoon per gal soil mix. Don't add bonemeal or bloodmeal since you will have ferts in the water. Adjust the fert water ph after adding the dynagrow to about 5.8 to 6.

How much dynagrow should you use? 1 1/2 teaspoons per gallon with 1/8 teaspoon epsom salts added along with it. This gives you 138 ppm nitrogen. The dynagrow is low in mag so thats the reason for the epsom.

n 138
p 76
k 82
ca 40 + baby bump off the gypsum
mg 10 + 15 from epsom
s 1 good reason for adding the gypsum

Happy growing! LOL.

 

[I2KanGrow]

Thanks, Blackvelvet - this is helpful.
I wish I was more helpful on my problem description, and performed a pH test on the drainage water.
I wanted to clarify/get clarification on a couple of things:
I'm using Premere ProMix BX... this stuff:


when I say 2 tblsp dolomite lime/gal - I'm referring to a 1 gallon container of Promix/Vermiculite/Perlite medium.
This is the lime I'm using:

which is pelletized, HERE'S a link to their website description/analysys of this stuff.

Would you still go with your recommendations, and should I fert with every watering?

One last question, please - You don't recommend vermiculite... OK, but what ratio do you feel I should use for my Perlite/Promix ratio... 50/50???

Thanks much again - I really appreciate it!!

 

[Guest]

Here's some pics of my Northern Light - about a month into reveg. I've noticed some brown on the edges/tips of the "old growth" leaves. This plant has recently been repotted into fresh Promix/Vermiculite/Perlite (2/1/1) - with added bone meal (2 tblsp/gal), blood meal (1 tblsp/gal), dolomite lime (2 tblsp/gal), and garden gypsum (2 tblsp/gal).

==============================================================
Ive seen this problem before..

Back on og we used to get problems just like this.....

This mix is very close to what we called bogs mix on og....

It worked great for bog.....

The problem was old bog was smarter than most who tried to do what he did....

Your mix is low in potassium......

so was bogs mix....

he compensated by using ferts high in potassium .....

those who did not had their leaves and and margin points go necrotic....

You have a potassium deficiency....

By the way..... I used to use dynagrow and never used epsom salts.....

the dolomitic lime was enough....

I dont really like your mix though....

IMO you should eliminate the bone meal....blood meal....gypsum and vermiculite...

Then use a complete fert like pbp.... and a little liquid karma......

 

[Blackvelvet]

You should be using powdered/pulverized dolomite lime not pelletized. You end up with lime chunks rather than an even distribution. You can get a 50 pound bag of dol. lime at Lowes/Homedepot for about $4. You should not need any anyway since promix is limed, perlite requires no lime, your going to adjust the fert water ph, and dynagrow contains cal mag.

How to test your soil ph: After you have ferted/watered the pot really well till runoff occurred, wait 30 minutes. The waiting is important. Then apply some distilled water to the pot surface till 1 or 2 ounces of runoff occurs and no more. Catch the runoff on a saucer or plate. Test this ph. Aim for 5.6 to 6.2 I bet your current ph is much higher than this. If you can tilt the pot after watering/waiting and get some liquid out, you can test that ph instead.

I would try 2 or 3 parts promix to 1 part perlite with no vermiculite. 30% extra perlite is common with icmag growers. You can skip the gypsum since you will be adding epsom salts containing 13% sulfur.

Fertilize with every watering but make sure you get alot of runoff pouring out the bottom of the container. You must adjust the fert water ph after adding the dynagrow to 5.8 to 6 or this whole thing will flop.

Follow the directions i gave very carefully. Get the old soil mix off the rootball even use a hose if needed. Your going to start fresh! Repot. Use plain water to get the new mix wet not fert water. Then use the liquid ferts. The liquid ferts look really good with that little pinch of extra epsom. :wink: The only flaw is the high amount of copper and zinc. Don't let your ph get too low or these could be slightly toxic.

It may take your plants a little time to respond to the new better conditions but I am sure you will be pleased in the future.

12/12: You will need to add a little extra calcium and magnesium with the dyna bloom fert 3-12-6. To make 5 gallons of fert water: 6.25 teaspoons dyna bloom 3-12-6 + 1/8 teaspoon calcium nitrate + 1/2 teaspoon epsom salts. If your gypsum will disolve in water (test it; I could not get organic traditions brand to disolve), you can use that at 1/8 teasoon per 5 gal instead of calcium nitrate but will not add nitrogen that you really need more of. Calcium chloride is a suitable calcium source lacking n under names like tomatoe blossom end rot stopper. I can't give you a rate till you get net weight and % ca in the bottle. If you want to use cal mag plus containing both calcium and magnesium, you would use 1 teaspoon per 5 gallons and add 1/3 teaspoon per 5 gallons epsom salts along with it.

n 50 + 7 from cano3 or cal mag plus
p 86
k 83
ca 33 + 9 extra added
mg 8 + 13 extra added

One last thought...Since k is only 83, you also could benefit by adding a little extra sometimes. I might throw in 1 teaspoon per 5 gallons 13-0-44 potassium nitrate (salt peter) every 4th fert in addition to the dyna bloom and extra cal mag of your choosing. This will add 38 ppm n and 107 ppm k. You should be able to find pot. nitrate maybe at the drugstore under salt peter or at a good garden center. Call around. If you have trouble finding it, I know exactly where to get it...send me a pm.

It is possible to add the potassium nitrate everytime with high light/good growing conditions but you will need to add even more cal mag everytime with it. You would add 1/4 teaspoon of both powdered gypsum and epsom salts per 1 gallon of water instead of the rate before. Calcium chloride @60 ppm ca could also be used too instead of gypsum. I would not use calcium nitrate @ 1/4 teaspoon per 1 gal + 1/4 teaspoon epsom or 1 1/2 teaspoons cal mag plus per gal + 1/8 teaspoon epsom because you will end up with too much nitrogen probably. If this is all you can come up with do it. Millenium cal mag does not contain n but may cause ph rises due to containing calcium hydroxide

Be careful, I switched back and forth from rates for 1 gallon and 5 gallons.

Using suggested rates above: Dynabloom + gypsum or calcium chloride + epsom salts + potassium nitrate everytime (approximate ppms)

n 88
p 86
k 190
ca 95
mg 48

Actually looks kickass.

I spent over 2 hours on this one post. Time for a joint.


.

 

[I2KanGrow]

I spent over 2 hours on this one post. Time for a joint.
.

Thanks MUCH for spending the time - it's very clearly written, and TONS of really great advice!!!

Hey, enjoy your joint!!!!

 

[Guest]

Black velvet is crazy.....


This should take one minute....


Promix is a little acidic which allows you to add dolomitic lime if you need to.....depending on what you are growing....

add some..... add some perlite....


use dynagrow and protekt for silica and extra K.....


done.....

 

[Grat3fulh3ad]

I'll tell you how to fix them... Stop with the bone/blood meal... Stop with the Lime and Gypsum... Use the pro mix and a proven complete hydroponic fert... Trying to heat up your mix, and then figure out a formula to suppliment it's weaknesses to fert with is just alot of unneccessary trouble, imho...

 

[James-Bong]

Black velvet is crazy.....

Don't you mean sprutco??? dump a gallon of battery acid in there with a pinch of stump remover....... that will do the trick

 

[VanGrow]

Use the pro mix and a proven complete hydroponic fert...

i use promix all the time.....as was said above.....u just need to add some perilite......i add a pinch of guano mixed in and a handfull of earthworm castings to give it some thickness per gallon and away i go.....i transplant once before flowering in veg...and again in the 1st week of flowering.....i top off plants with some fresh promix at the 5 or 6 week mark of flowering....promix has a good charge of lime for a month or so.....so by either transplanting on a schedule and topping off with the promix my ph stays stable with little effort as long as my water is in the low 6's ph wise....
good luck....



I offer my opinion as ..... i actually grow weed.....
VG