# Feeding considerations



## Kate Boyce-Miles (Jun 9, 2020)

Hello. I was wondering what members think of my feeding regime (for slippers) and if I should alter it in anyway?

I feed every three out of four waterings, and flush with plain water on the fourth. I use either tap water or rain-water. The tap water is soft. 

With fertilisers I alternate between Akerne's rain mix and Dyna-gro 7-8-6, both applied at 1/2-1g per two litres of water. Once per month I also feed with Epsom salts and calcium nitrate.


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## Ray (Jun 9, 2020)

Akerne's @ 13%N, is providing 75-125 ppm N over that range - good for weekly application, and no problem skipping a week by using plant water. The D-G product is providing a shade over half that.

Personally, I'd use the Akerne product alone, and not bother with the D-G, Epsom Salts or calcium nitrate.


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## eds (Jun 10, 2020)

Hi Kate,
I mix the rain mix 50:50 with calcium nitrate to get an NPK proportion nearer K-Lite.
I then water about once every month (or two) with Kelpmax.
It works for me so far but not massively different to what you're doing.
Ed


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## Kate Boyce-Miles (Jun 10, 2020)

Ray said:


> Akerne's @ 13%N, is providing 75-125 ppm N over that range - good for weekly application, and no problem skipping a week by using plant water. The D-G product is providing a shade over half that.
> 
> Personally, I'd use the Akerne product alone, and not bother with the D-G, Epsom Salts or calcium nitrate.


Thank you for the advice, Ray. Do you advise foliar feeding? At the moment I just apply it to the roots.


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## Kate Boyce-Miles (Jun 10, 2020)

eds said:


> Hi Kate,
> I mix the rain mix 50:50 with calcium nitrate to get an NPK proportion nearer K-Lite.
> I then water about once every month (or two) with Kelpmax.
> It works for me so far but not massively different to what you're doing.
> Ed


Thank you for the reply Ed. I assume the calcium nitrate does not interfere with any of the components of the rain mix when they are used together?


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## eds (Jun 10, 2020)

Not that I'm aware of! I mix them together dry in small batches in a tub to make dosing easier. I then make up two 5l sprayers of RO water with this mix at a time which usually last about two weeks. I've not noticed any precipitation or nutrient issues with my plants so far.


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## Ray (Jun 10, 2020)

Kate Boyce-Miles said:


> Thank you for the advice, Ray. Do you advise foliar feeding? At the moment I just apply it to the roots.


No, I don't. Many orchids have waxy cuticle layers on the leaves that are an evolutionary adaptation to slow water loss. It seems to me that a layer that interferes with loss will also interfere with uptake.

Then there's the preference of the uptake of nitrogen form: Orchids can directly use nitrogen as nitrates, ammonium compounds and urea to different degrees. Most orchid fertilizers contain the first two. Nitrates and ammonaical nitrogen are preferentially absorbed by the roots and less so by the leaves. The converse is true of urea.

Adding to Ed's mixing comments: as long as the compounds are mixed in dilute solutions, there's no issues. Precipitation may arise if you try to mix convcnetrated solutions.


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## Ozpaph (Jun 21, 2020)

How much calcium nitrate per litre to make 100ppm N?


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## Ray (Jun 21, 2020)

It’s 2.3/%N give ml/L for 25 ppm N, so 9.2/15.5 = 0.59 ml/L for 100 ppm N calcium nitrate


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## Ozpaph (Jun 22, 2020)

Thank-you Ray. So, I guesstimate about a level teaspoon of prilled CN to 9l watering can.


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