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Old 10-08-2009, 10:35 AM
Luches Luches is offline
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Join Date: Jul 2009
Posts: 177

Hi again - you're welcome!
Originally Posted by Errol View Post
If I'm reading them correctly, it seems that you think the mix could certainly do with some magnesium sulphate - and that the concentration should be 7gms/litre Hydrosol, 7gm/litre calcium nitrate, 4gms/litre MgSO4 and possibly 1 gm/litre of calcium chloride? Am I close or on the wrong tram altogether?
Well, I bet you got confused with the decimals. It's 0.7 (zero point seven) gram per liter (litre), 0.7 and 0.4 Mg. (obviously only 0.1g CaCl/liter)
Attention: 7 gram per liter of both would probably kill your plants over night.

Originally Posted by Errol View Post
I would keep on doing what I am now ie using equal quantities of Hydrosol and calcium nitrate?
Indeed equal quantities of both in the present example of a mix.

Originally Posted by Errol View Post
This would be at odds with my thinking at the moment ie that the level of N in the 50/50 mix is possibly too high, causing too much vegetative growth.
But equal quantities only determines the proportion of N vs. P and K, it doesn't say if the N-content is too high or not. It actually depends on how much Calcium Nitrate is used per Liter. I bet you were using more than 0.7 g/l, were you...?

Originally Posted by Errol View Post
What are your thoughts on mixes referred to in the following link?
Well, well.... I haven't read them trough and had no time to check on them in detail, but I've found some things I'd not necessarily agree with straight away. They seem to lean on Dr. Resh a lot and (all due respect) he is going pretty heavy duty (avoiding to say aggressive) on feeding. On the other hand, they are playing "cheap" with Mg and Sulfur. While the standard content of Mg is around 50, and if using Magnesium sulfate, Sulfur should- actually will be around 80 PPM anyway. Which is just fine because most plants require that much of later elements. Dr. Cooper and Hoagland formulas are indeed the basics of all formulas, but also dinosaurs and perhaps a little outdated. But then again it's damn hard to find good and reliable sources for nutrient formulas that are up to date.

If I understood your goal and concept right, you are growing various plants and not mainly leafy vegetables. In that case I recommend a N-content not exceeding 150-170 PPM of N. Lettuce would be happier with some 200-220 PPM, but tomatoes, peppers (as well as cucumbers) and most nightshade wouldn't really like that.

210 PPM of K as an outcome in my example is not really high (not good enough actually), - for tomatoes 280 and plus would be better. But with Hydrosol there are clear limits of increasing K content, without exceeding P limits (50-60 PPM). Well here one could push a little and increase to 0.8-0.9 gram/liter of Hydrosol without doing amy harm. Even somewhat further if more K is badly required (high yield of tomatoes, capsicum).

PS: the problem with Calcium Nitrate is generally that you need to add sufficiently to cover Ca needs (140-180 PPM), and obviously go too high with N. With a small part of CaCl you can cover Calcium needs, without exceeding N-content.

Hope all this is intelligible and helpful.

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