Fertilizer rate?

[mooch]

I have come across this product that I want to try, it's liquid dolomite enriched with seaweed. My question is at what rate should I try it?
The ingredients are 35% w/v calcium, 12% w/v magnesium.

[Wynn Dee13]

Here is a link to Ray's site about fertilizers. At the bottom of the page there is a link to a page that helps you calculate the dose. Are you using that product with a complete fertilizer? I might be wrong but the product you are talking about sounds like a suppliment not a fertilizer. Fertilizers & Plant Nutrition

[mooch]

I am going to use it with my regular NPK fertilizer, to boost calcium and magnesium.

[Wynn Dee13]

Okay. I don't know how much you would use. Hopefully Ray or someone who knows more about this can help.

[Ray]

You sure it's a weight/volume percentage, and not weight/weight?

In any case, I'd probably ratio it so the Ca is somewhere between 50% and 100% of the N - Let's assume your fertilizer is 20%N, and you use it at 6 ml/L. To get the Mg to a 20% level, you'd need 20/35 x 6 ml = 3.4 ml of the liquid dolomite stuff, and with half that being 1.7, I'd feel comfortable and either 2 or 3 ml/L.

Be sure to check your pH!! Dolomite can raise it significantly.

[mooch]

Thanks Ray, it is weight/volume, I will give it a go. Also what is the ideal ph for a fertilizer mix.
Love your website by the way, wish we had first Rays in Australia.

[Ray]

While I'm quite sure the "ideal" pH varies with the plant, and that most are reasonably flexible, I have found that anything from 5.5 to 6.5 is acceptable to most.

[orchidsamore]

Dolomite can easily push the ph up over 8 and plants lose the ability to absorb calcium and magnesium when the ph goes over about 7.4. I would be hesitant to use this product especially as the dolomite does not add anything to the plants growth.

[POLKA]

whoa
dolomite is high magnesium limestone
what is there that is not to like for orchids?

If you use something to keep the pH down, you would have excellent addition to your fert program.

What am I missing??

Rex