Magnesium defiency? not sure (pictures)

[Guest]

sup guys, I have 2 afghani plants that appear to have a magnesium defiency. but I would rather have more experienced people diagnose the problem. They have been fed fox farm grow big (6-4-4) only 2 times. the last time being about 4 days ago.

I have heard that this afghani strain from nirvana was very sensitive to fertilizers. I used 1/4th teaspoon the first time, and 1 teaspoon the second time.

These are pictures of both plants leaves.

 

[sproutco]

What is in your soil mix and is there dolomite lime?

 

[Guest]

nope, no dolomite lime. its outdoors. I cant remember when I planted them. but its been a good 3-4 weeks atleast and they have not shown any sign of problems up until now. I have another plant thats about 3 months old less then 10 feet away from it and it shows no sign of problems. the first i think 1 foot or so is some potting soil ive used and that these have grown in since seedlings. from there its just regular dirt in the earth.

I have epsom salt, and dolomite lime in bags already from previous grows if I need to use any.

 

[sproutco]

Does grow big contain calcium and magnesium? What are the % on the bottle? You can use the fert calculator in my signature below to figure ppms of your nutrient solution. Better way of doing things than guessing by teaspoon (1 teaspoon = 5ml.) If there is no dolomite lime in your soil, I bet the soil has gotten acidic. So, this might reduce the amount of magnesium and other nutrients available. Aim for about 6 ph. Directions for testing ph are in my signature below. You should ideally fertilize lightly with every watering using about 100-150 ppm nitrogen as part of the complete ferts. After adding the ferts to your water, adjust ph with an acid or base. This is important because you don't have lime as a buffer. Directions are in my signature for making your own ph up and down. If you need to add calcium and magnesium to the grow big, use 1/4 teaspoon of both powdered gypsum and epsom salts per gallon of water (3.8L). This would add 30ppm magnesium and 70 ppm calcium. You should raise both together so you keep a balance. You want 4:2:1 potassium to calcium to magnesium.

 

[Guest]

0.60% Magnesium it says. I see no mention of calcium on it. THis is all a bit confusing for me, so im trying to understand it all.

So to prevent this from happening again, I should use 1/4 teaspoon of epsom salt per gallon of water everytime i fertilize?

after adding the ferts to your water, adjust ph with an acid or base.

im still trying to understand the process of this. take a gallon of water, add my grow big fertilizer, test pH, then add some pH up/down to the gallon of water to make it around 6-6.5?

I have a pH meter and will go test the soil right now, if i wanted to fertilize them right now. should i use the second method above i said? which would be the correct thing to do.

edit - not sure if this is any helpful but the tap water i regularly use tests 8.5 pH before being touched. after adding half a teaspoon of grow big it brings it down to 7.0 pH. (ive been using 1 teaspoon per gallon and giving both plants half a gallon of water.) so I would assume if i used 1 teaspoon the water would be down to about 5.5. am i going in the wrong direction here, or does this make any difference?

 

[sproutco]

Click on this to enlarge. When the picture appears larger, move your cursor to the bottom right corner and another option appears to make it even larger.



You want 150 nitrogen. 4:2:1 potassium to calcium to magnesium.
1/4 teaspoon epsom per gallon of water = 30 ppm magnesium
1/4 teaspoon powdered gypsum = 70 ppm calcium

Give it a shot and see what you come up with.

 

[bartender187]

Your PH water is rather hard. If I was you I would let a few gallons sit out (I use a rain barrel) over night. You will notice that the PH changes alot in the first 24hrs and after the night the PH should be close to 7. Chlorine and other chemicals evaporated out of the water over night. Doing this will allow for you to PH adjust your solution and know that it wont change drasitcally after you have fed your plants.

PH pens are made for water or soil, not both. If you have a water PH pen, then test the solution you put in and collect the run off. Then test the runoff, by seeing how much and in what direction (acid or base) the PH changed to you can come to some sort of conclusion on whether your soil PH is in the right range.

Also I personally dont feed with epson salt every watering... My plants seem to do fine with every other watering or even once every two weeks.

 

[Guest]

How can I collect the runoff? I know how to do it with a pot, but as for being in the ground I dont have a clue. would also like to say thanks for the help both of you. it seems like whenever I think everything is going right something goes wrong. im glad to know there are people here willing to help =)

Im working on that calculator, looks confusing but once I give it a try im sure ill figure it out. I dont know what on the bottle of fertilizer im looking for to enter into the calculator though.

 

[sproutco]

Click on this to enlarge. When the picture appears larger, move your cursor to the bottom right corner and another option appears to make it even larger.



You want 150 nitrogen. 4:2:1 potassium to calcium to magnesium.
1/4 teaspoon epsom per gallon of water = 30 ppm magnesium
1/4 teaspoon powdered gypsum = 70 ppm calcium

Give it a shot and see what you come up with.

Mix the soil 1 part to 1 part distilled water. 1/4 cup of soil +1/4 cup distilled water. wait 30 minutes after stirring well. Test this ph.

 

[Guest]

I got some results from the calculator, but I have no idea what they mean or if they are right.
900 net weight in grams
946 milliliters
1 teaspoon/5 ML
3.1% N03 @ 39 ppm
2.9% NH4 @ 36 ppm

nitrogen total @ 75ppm

How do I use this now? still confused

edit - for above post, I am already doing that, soil is sitting in the distilled water now. I read the post on testing the pH of soil collecting from the rootball etc. I was just wondering if there was a different way.

whats the pH of distilled water supposed to be?

 

[Guest]

sproutco i dont suppose you have AIM, or IRC do you? if you dont mind helping me through that, would probably be easier then over the forums. i think i understand where your leading me with the calculator though. with the fertilizer + water im getting 75 nitrogen ppm. I need to raise it up to 150 which can be done by adding 1/4 teaspoon of the salt/powder correct?

 

[sproutco]

1 teaspoon got you 75 ppm

2 teaspoons would be double

You want 150 ppm nitrogen so...

How much would you use?

put 10 ml in the calculator instead of 5ml; that would be 2 teaspoons

enter all the other % like mag, potassium, etc...

you want 4:2:1 potassium to calcium to magnesium; get close not perfect

1/8 teaspoon epsom gallon = 15 ppm magnesium
1/8 teaspoon powder gypsum = 35 ppm calcium

Example: if you have 84 potassium you want 42 calcium and 21 magnesium. This is not alot of any of these. Potassium ideally should be at the same level as nitrogen. You might consider adding more potassium and then also raising calcium and magnesium with the ratio.

calcium nitrate could be used instead of gypsum at the same rate but will add nitrogen; 1/8 teaspoon adds 28 ppm n and 35 calcium; not much nitrogen really

 

[Guest]

Im not great with math at all, I dont understand what you mean by 4:2:1. I really dont understand anything your saying, its like a foreign language to me.

 

[sproutco]

Here is how you might improve your nutrient solution

Here is how you might improve your nutrient solution

If 1 teaspoon got you 75 ppm nitrogen, then 2 teaspoons would get you 150 ppm nitrogen. This is what we want.

So 4:2:1 potassium to calcium to magnesium

With the 150 nitrogen, you got 83 potassium. Do divide by 2 to get amount of calcium needed. 83/2 = 42 and then divide by 2 again to get amount of magnesium needed 42/2 = 21

So with 2 teaspoons you got enough magnesium 21 and 16 are close but not any calcium. You should add 1/8 teaspoon per gallon gypsum to get 35 ppm calcium which is close enough to 42.

But wait!

I told you 83 potassium is low really and should be about 150 like the nitrogen.

So add more potassium. You can use potassium nitrate 13-0-44 for this. This is the active ingredient in some stump removers at hardware stores. Dexol is a brand.

1 teaspoon potassium nitrate = 5.6 grams
so 1/8 teaspoon = .7 grams
Enter 13-0-44 and .7 grams into the calculator
It should look like this: Click on this to enlarge and again in the corner of the picture to get even larger...


So along with the potassium we added we also got some nitrogen. This might be too much so lets reduce the grow big to 1.5 teaspoons (7.5ml) instead of 2.

Put this in the calcutator. It should look like this: Click on this to enlarge and again in the corner of the picture to get even larger...


Now add the results together. 1/8 teaspoon potassium nitrate + 1.5 teaspoons grow big. What did you get?

n 113+24=137
p 33
k 63+68 = 131
ca 0
mg 11

Looks pretty good. Nitrogen is almost 150 like we want and potassium is now closer to the n level.

We definately need calcium and magnesium with this. How much? 4:2:1

Divide 131 k by 2 = 66 this is how much calcium you need
adding 1/4 teaspoon powdered gypsum = 70 ppm so that works out good

66 divided by 2 = amount of magnesium you need ...33
But you already have 11 so 33-11= 22 still needed
1/8 teaspoon epsom salts = 15 ppm magnesium so close enough 15+11=26

In summary per gallon of water:
1/8 teaspoon potassium nitrate
1.5 teaspoons grow big
1/4 teaspoon powdered gypsum
1/8 teaspoon epsom salts

n 137
p 33
k 131
ca 70
mg 26

Looks great!

 

[Guest]

so this will fix it, or prevent it from happening again. or both? also where can i get powdered gypsum and potassium nitrate? never seen either for sale at home depot. thanks for the help btw.

 

[sproutco]

I have seen powdered gypsum at home depot in 5# bags. Potassium nitrate is in some stump removers because it is a safe form of nitrogen to sell. Dexol, green light, hi yield, and grants are some brands. Check the package for ingredients and not pure copper for example. Just call around to garden centers, ace, true value, home depot, etc... rather than waste gas. If you can not find the potassium nitrate add 2 teaspoons grow big plus 1/8 teaspoon powdered gypsum. If the magnesium looking problem does not go away with the increased dose of grow big and your adjusting you ph water after mixing, add 1/8 teaspoon epsom salts to boost levels along with everything else. The second formula with the potassium nitrate is excellent the way it works out. It closely resembles the famous Johnson hydroponic formula. Look that up on the internet and compare the numbers we got. Your has a little more nitrogen.


http://www.valuegardens.com/images/labels/d0524_label.pdf pure potassium nitrate

http://72.14.209.104/search?q=cache...+depot+stump+remover&hl=en&gl=us&ct=clnk&cd=9

Be sure to let me know if you find the stump remover and gypsum. I want to know how your plants respond.

Good luck in the supply hunt!

 

[Guest]

Will let you know tommorow, Going to buy some gypsum in an hour or so. Pretty sure I can find the stump remover as well.

 

[Guest]

no sign of improvement so far with the little ones, but I did notice this. this appeared within hours of watering the little ones with the gypsum/grow big mix.

So far, it is only on about 4-5 leaves total, I THINK I dripped some onto those leaves though, causing the fert/gypsum water to be burned on the leaves by the sun. Is that what it looks like?

I looked through the sick plant thread and noticed it looked like a calcium defiency(which would be sufficienct from the gypsum powder, but how would 1/4 teaspoon into 1 gallon of water cause that? is that too much). The big plants main stem is about 3 feet away from one of the smaller plants I watered with 1/4 teaspoon of the gypsum. I really dont think it would have effected the big plant.

No other leaves on the plants except for the ones that i couldve dripped some of the water on show any sign of it.

 

[Guest]

The smaller plants are now showing the same thing leading me to believe that it was from the gypsum powder, how was this suppose to figure the magnesium defiency ni the first place? the only thing i see udner mag defiency on this site was epsom salt and dolomite lime.

Now I have no idea what to do, because it seems like each time I try to fix something I end up hurting it worse.

 

[dre86]

Dude, imo your plant is looking fine