Is this a magnesium deficiency or nitrogen?

Hey guys so one of my plants leaves are getting yellow like in between the veins, the veins are still green and the growth hasn't stunted or anything... at least i don't think it has. But yeah it'd be awesome if anyone could help me figure out what my plant wants from me right now cos I'm a bit lost for a solution. I've been adding a small amount of calmag to my res so i don't think its a magnesium deficiency but by small amount i mean like 2-3ml for a 7L res. Anyway heres a photo of it so you can see whats going down

ok i just realised that the picture i uploaded got saved as a pdf and so it downloads if you click on it so here it is again in a better format

Mg def. Give 1/3 tsp/gal epsom salt. I'd say 1/2 tsp, but the plant looks younger than when people usually see mg def.

Also, in the future it's better not to wash out the photo as you did (to highlight a small un-washed area). It would have been better to see the entire plant's condition (with the same exposure/color saturation).

az2000 said:

Mg def. Give 1/3 tsp/gal epsom salt. I'd say 1/2 tsp, but the plant looks younger than when people usually see mg def.

Also, in the future it's better not to wash out the photo as you did (to highlight a small un-washed area). It would have been better to see the entire plant's condition (with the same exposure/color saturation).

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Thanks man ill do that! and yeah... that was only like that cos I was procrastinating lol I shall find other ways to waste my time in future

whats your soil?

Diabolical666 said:

whats your soil?

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50/50 coco and perlite mix

Not enough calmag. My plants in straight coco showed calcium and magnesium deficiencies until I increased to 2.5ml/gallon. Even when i use a diluted solution of nutes I never use less than 1.25ml/gallon calmag, including during flushing out the nutes if they build up too much. Since that switch no problems.

Cal-Mag - minimum 1ml per litre. Preferred 2ml per litre and set the PH accordingly. 5.8 for Hydro and 6.5 for Soil.
If the PH isn't spot on it won't uptake it! You won't do any harm with cal mag. It's uptake is PH related.

I would stay away from epsom salts. I had to do a complete flush after a dose of emergency epsom, waiting on the Cal-Mag. Epsom should be your last resort. It also sends your PPMS SOARING, making it hard to know what and when to feed without a flush!

slinkysaurus said:

I would stay away from epsom salts. I had to do a complete flush after a dose of emergency epsom, waiting on the Cal-Mag.

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Epsom salt is just the mag part of "calmag." It's widely used by cannabis growers. The problem with using calmag for an mg def when there's no cal def is that it could throw off the ratio of ca to mg (which is an important ratio.). Calmag may work, it's just treating something that doesn't need to be treated, increases N (which may not be what is needed), etc.

az2000 said:

Epsom salt is just the mag part of "calmag." It's widely used by cannabis growers. The problem with using calmag for an mg def when there's no cal def is that it could throw off the ratio of ca to mg (which is an important ratio.). Calmag may work, it's just treating something that doesn't need to be treated, increases N (which may not be what is needed), etc.

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I don't a argue with it not being 100% magnesium sulphate. I just find it a pain in the ass when it comes to wreaking havoc with EC. Cal-Mag is just my preferred route as it's full of other trace goodies your plant needs in all stages. For me it's just a hell of a lot easier

Plus, Calcium and Magnesium are literally side by side on the PH chart for Soil and nose to nose for Hydro. They so often go hand in hand with one another, Epsom is a quick fix but I found that you often then get a Cal deficiency after fixing the Mag!
Hence, cal-mag! 2 birds one stone.

az2000 said:

Epsom salt is just the mag part of "calmag." It's widely used by cannabis growers. The problem with using calmag for an mg def when there's no cal def is that it could throw off the ratio of ca to mg (which is an important ratio.). Calmag may work, it's just treating something that doesn't need to be treated, increases N (which may not be what is needed), etc.

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Exactly. For this particular case, cal-mag+ is just the wrong solution. I was actually going to suggest that there's too much lime in the medium rather than not enough Mg. Adding cal-mag+ would be totally pointless and would just make the Ca:Mg ratio worse!

slinkysaurus said:

I don't a argue with it not being 100% magnesium sulphate. I just find it a pain in the ass when it comes to wreaking havoc with EC..

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That's a pretty bad reason. It "wreaks havoc" with EC because it's more concentrated. Cal-mag+ is overpriced watered down calcium nitrate, magnesium nitrate, and iron chelate.

Magnesium sulfate dry is much better value, and calcium nitrate dry is waaay better value.

slinkysaurus said:

They so often go hand in hand with one another, Epsom is a quick fix but I found that you often then get a Cal deficiency after fixing the Mag!
Hence, cal-mag! 2 birds one stone.

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Ca++ and Mg++ ions antagonize each other, and thus proper ratios must be maintained to allow a good uptake of both.

To each their own =] Was just sharing what's worked for me as an easiest fix. We all have different requirements with our water!
After trying both, I really am a fan of the Cal-Mag. Epsoms does work for a MAG deficiency and it does it very well, it just didn't fix everything for me like the Cal Mag did and having the PH buffered and set correctly.

In Soil, below 6.5 PH you won't uptake ant Mag OR Cal. In Hydro, above 5.8 or below and you lose one of the two and sacrifice others. That's the only reason i was recommending Cal-Mag!

slinkysaurus said:

In Soil, below 6.5 PH you won't uptake ant Mag OR Cal. In Hydro, above 5.8 or below and you lose one of the two and sacrifice others. That's the only reason i was recommending Cal-Mag!

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A calmag product shouldn't be different in that regard. When you supply mg by itself (to treat an mg def, or ca to treat a ca def) it's subject to the same availability chart.

The only benefit I see of a calmag product is ease of use.

Another benefit of calmag is when a ca def arises and the grower hasn't taken steps to treat it individually. Mg is easy to find. Just go to the grocery store's health & beauty section for epsom salt. But, when you need ca, it's not clear what to do. You can get calcium carbonate from crushed up antacid tablets. But, that's slow acting (probably only for soil, but still slow). Calcium nitrate is fast acting, but not as easy to find in a hurry. It also supplies N which I'd prefer not doing because there's another choice in soil:

For ca def I use dissolved eggshell. That's calcium carbonate with the carbon part removed, the time consuming breakdown performed in advance. I prefer this over a "calmag" product because it treats a ca def more specifically. But, you have to start making it a month in advance.

I agree with you that using a calmag product is more common. For that reason your advice isn't necessarily bad or "off." It's just that a person can treat deficiencies more specifically and with less cost. Epsom salt isn't any harder to use than "calmag." But, admittedly, treating a ca def is.

az2000 said:

Calcium nitrate is fast acting, but not as easy to find in a hurry. It also supplies N which I'd prefer not doing because there's another choice in soil:

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It's easy to find in a hurry when you order it in 2009 and have a giant bag laying around since then.

In soil, I agree that calcium nitrate isn't the right choice, but in hydro, it's the only choice. The fact that it provides N is why. It's N or no solubility. It annoys the crap out of me when hydro noobs look for a source of calcium without N. People can be pretty stubborn when you tell them there's only one way to do something.

That being said, Ca should come from Lime or bonemeal when in soil, and it should be built into the soil. Using cal-mag+ in soil is kind of stupid actually.