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Chelated micro-nutrients

Posted by andrefer (My Page) on
Fri, Feb 26, 10 at 7:44

I'm starting a small experiment in NFT-hydroponics... I'll prepare my own fertilizer solution using peter hydrosol as a starting point... I think I'll need to suplement it with an equal portion of calcium nitrate, correct?
Regarding micro-nutrients... is it fundamental to use them in chelated form or can we use them as other inorganic salts which are far cheaper?

best regards


Follow-Up Postings:

RE: Chelated micro-nutrients

If the peters is the same as the soluble hydroponic special formula I listed on another thread, the only micro's you'll need to add is chelated iron. I don't add it to my nutrients, but I am fairly certain I have some in my well water.
Also, assuming similar hydrosol, you'll actually be using about 3 parts hydrosol to 1 part cal-nite. plus 0.5part epsom salts.

RE: Chelated micro-nutrients

The hydrosol is described in

I've noticed several different types of nutrient solutions available which is natural... nevertheless what is not natural is the mistakes made between chemical quantities and ppm in final solution
Can you check on this?

RE: Chelated micro-nutrients

Ol Andr,

1. The portion of calcium nitrate you'll add (to Hydrosol) will determine the Nitrogen (and calcium) content of your formula. It should/will be less for tomato and night shade and more for leafy vegetables as lettuce, spinach etc.

3. Micro nutrients do not need to be supplied in chelated form except Fe (iron), because if Fe is not used in chelated form, it is not very stable in the solution and will not be available to plants for very long. Other chelated elements like Cu, Mn and Zn are said to be available trough a larger scale of PH, they probably are. But if you keep your PH in a range between 5.8 and 6.2 (and even above) the much cheaper sulphates will be available to plants as good as in chelated form.

4. As I can see Hydrosol even has them in chelated form and sufficiently as well, even Fe looks Ok to me. The Mg content is a bit low and could be complemented indeed (depending on Mg content of tap, source etc- water). You should check that to be certain.

5. You might think that if you add the required quantity of Calcium Nitrate, you will have only about half as much micro nutrients, and hence not sufficiently. Well, this isn't exactly the case as the amount of micro nutrients in ppm is relative to the Liter used for the final solution. Look at it like this: in Hydrosol the Nitrogen (and the Ca) is missing, and the other elements are (in some way) calculated for a certain amount of liters, so are the micro elements. If now you put it all together the content in micro elements is still fine and sufficient in relation to the concentration/amount of water you finally use. Well, if you'll make up a formula with very high Nitrogen, lots of Mg added and perhaps even some P, you'll have indeed less and less ppm of micro elements at some point ... but in a normal case (or standard mix), the content will be sufficient.

6. Be careful when calculating the amount of Calcium Nitrate to add, because with 5-11-26, only the N part is actual, but P and K are conventional and need to be transfered to actual. This is probably what was confusing you and why you were assuming that you need equal amounts of Calcium Nitrate and Hydrosol.

Use this simple formulas, to convert to actual percentage and to avoid ending up with wrong proportions (or some formula you didn't actually want to have):

N= 1
P = P2O5 X 0.44
K = K2O X 0.83

In some rare case these may also be useful:
Mg = MgO x 0.60
Ca = CaCO3 X 0.4
Ca = CaCO3 X 0.23 (dolomite)


RE: Chelated micro-nutrients

PS: what I was narrating about the other chelated micro elements in the previous post, needs to be rectified a bit. It is more complex than that. In fact in chelated form they are supposed to be more stable (anyway) and not prone to precipitation. Chemically bound for a slow(er) release and longer available. Furthermore, when used in sulphate form they may be found in higher concentrations in some grains or crops (less when used in chelated form). Both have different properties (advantages) in solutions, foliar sprays or in soil fertilizer, etc, etc. Well there is some information around (Google is your friend) for those who want to explore this topic deeper.

Fact is that many hydroponic nutrients use these micro nutrients in much less expensive sulphate form "only" without any deficiencies.

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