# Magnesium (Mg) deficiencies



## Melnick (May 25, 2009)

I am trying to find a way to fix Magnesium (Mg) *deficiencies.*  I know I am having issues with my ph.  I have tried PH at 6.5-7.0 and still my runoff is below 6.0. I was able to get the ph up to 7.4 and the runoff was 6.0, but that's not good.  Luckily my girls continue to grow slowly.  The symptoms start two-three week in veg stage and continue thru flowering. I am using Happy Frog, which should keep the soil at 7.0.  I have lime, but not sure how to apply it.  I have not notice any bugs. I am using 6.5 pots, because I am growing plants.  I am missing something, but what? Thanks.

Outdoor
Fox Farm
N/L 6.5 pots
Happy Frog
2 in veg stage, 2 in flower stage


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## Melnick (May 25, 2009)

I forgot to add, I spray with epson salt daily.


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## Alistair (May 25, 2009)

I'm terrible at testing soil runoff for pH.  What kind of pH meter are you using?  Is it a decent digital one?    It is popular advice to water with a solution of pH 6.2-6.4. Some like to water with a pH around 6.5-6.6.  Try not go above 6.8.

Your soil should be a good soil that is able to help buffer the pH within the proper range.  Personally, I as well as others, use Fox Farm Ocean Forest (FFOF) soil.  All some of us do is add a tablespoon of dolomite lime per gallon of soil to help maintain proper pH and it contains magnesium and calcium as well.

Is it possible that you've over-fertilized the plant?  If so, that can upset your pH and lockout the magnesium. 

If you have good soil and properly pH'd water, then testing runoff, although not a bad idea, shouldn't be necessary.  I gave up on testing runoff a long time ago, with no problems at all.  Hippy has a good method of testing soil runoff pH, but it doesn't work for me.  If I were to test runoff (and I've done it before ), I would water until there is lots of runoff.  Then I'd pour it back into the pot and let it run out again.  If you don't have much runoff the second time around, then add more water until you have lots of it again.  Keep re-pouring the runoff water through the dirt until there's still plenty of it.  Then, keep pouring it through a few more times.  In my opinion, this will give the water enough time to dissolve all the pertinent ions, giving you a fairly accurate reading.

nine times out of ten, a nutrient deficiency is caused by improper pH. There could be plenty of Mg in your soil, but if the pH isn't correct, then the plant won't be able to absorb it.

I hope this helps. If nothing ever went wrong with my plants, then I'd never really learn anything.  Work on those plants, make them healthy again, and learn from it.  Be patient, and good luck.


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## Rockster (May 25, 2009)

Hi Melnick,

 why Mg deficency,what symptoms have you been getting apart from those leaves you showed as that necrosis on those leaves could be due to various things?

Are you operating a good wet and dry cycle,watering when the pot is quite dry?

Any chance of whole plant pics?


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## Alistair (May 25, 2009)

Yeah, ask Rockster.  Rockster is quite knowledgeable, he'll set you straight.

Rockster are you male or female?  I ask because your avatar is proudly displaying a wedding ring, or something of that nature.


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## Melnick (May 25, 2009)

You brought up some good points.  My digital ph monitor went bad, so I am using a ph test solution for now.  It's hard to get a good reading, but I know I am in the ball park.  I try not to test the runoff, but something is wrong.  I have always had this problem with every grow. I want to use lime, but am nervous about it.  I might try the lime on one plant with small dosage and see what happens.  This is a pic of my ph level I am using now. Thanks.


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## BuddyLuv (May 25, 2009)

using the color code pH test kit is probably the big issue. The run off will become discolored using soil and nutes will even change the color as well. You need a good digi pen to get an acurate reading.


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## Melnick (May 25, 2009)

I experimented on bending, explains the bend.  As you can see all the fan leaves died off.  I was trouble shooting with the Magnesium (Mg) deficiencies. I have experienced the something every time, starting  about threes into veg. First pic Rockster, is the start of the problem and the rest are today.


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## Alistair (May 25, 2009)

Melincik I used to use pH reagent drops and I too thought they got me in the ball park.  I've discovered that pH reagents don't seem to be all that accurate.


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## BuddyLuv (May 25, 2009)

What kind of water are you using? Chlorine can mimic Mg and Cal deficiency.


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## LEFTHAND (May 29, 2009)

where can one get a decent but cheap ph tester. since im using the drops as well... and from what i have just read they aint to good!!!

a point in local stores would be nice...


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## beensoup (Jun 1, 2009)

Doesn't necessarily look like Mg deficiency.


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## CoolAsAFan (Jun 1, 2009)

is that not more of a Mn def? 
you say you spray with epsom everyday, since def first appeared or earlier then that? daily for how long now?


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## Terminal Head Clearance (Jun 1, 2009)

I  recently experimented with Mg defiency . wasted 6 months to learn some plants are pain in the yu name it region but....As difficult as it was this first test. the smoke and its not even perfectly cured.. i.e. long term ice storage.   

If its this good now.


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## Terminal Head Clearance (Jun 1, 2009)

spray them with epson salts

every plant is different

and each needs their own individual

fertilization

Don't be scared 

its simpler than it sounds


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## CoolAsAFan (Jun 2, 2009)

just had the same problem with one of my bluebuerry seedlings. was definately because of a low ph as i completely forgot to adjust my nute solution a couple days ago and it was lower then 4.5 i think lol. my runoff was slightly lower then 5 with 7.5 ph'd water. so i flushed and checked today and there was almost an explosion of new growth. now if only i could remember to add my lime to my veg soil mix


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## lordhighlama (Jun 2, 2009)

LEFTHAND said:
			
		

> where can one get a decent but cheap ph tester. since im using the drops as well... and from what i have just read they aint to good!!!
> 
> a point in local stores would be nice...


 
I've used this site in the past and they are the cheapest I've found on the internet + they have free shipping.

hXXp://www.eseasongear.com/


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## Super Silver Haze (Jun 2, 2009)

sunstone herbals on ebay has inexpensive digital ph meters.


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