Help with fertiliser and water quality

[kiwi]

Hi all,
Could someone please provide some feedback as to my water quality and choice of fertiliser? The media I use is the Birk "pretty good mix". I have a wide variety of Paph. species. The water quality results (in g/m3 unless stated otherwise) from my supply are as follows.

Alkalinity (CaCO3) = 74
Ammoniacal Nitrogen (NH3- N) = 0.038
Chloride = 7.6
Conductivity (mS/m) = 18.8
Copper = 0.0023
Manganese = 0.0175
Nitrate Nitrogen (NO3 -N) = 0.122
Nitrite Nitrogen (NO2 -N) = <0.002
pH = 8.1
Phosphate (PO4 -P) = 0.26
Potassium = 1.58
Sodium = 11.3
Sol. Orthophosphate (PO4 -P) = 0.085
Total Dissolved Solids = 129
Total Hardness (CaCO3) = 71

The fertiliser I use is Kristaline "white" and is as follows. N (17), P (6), K (18) and Mg (2). I use approximately 1/4 teaspoon per 10L.

My plants are all fine (touch wood) at the moment but was interested in any feedback (more/less/change?).

Thanks in advance.

 

[Stone]

I presume 18.8 mS/m = 0.0188 dS/m (I think thats right )
If it is, your water is very pure and the only thing to take notice of is your pH (if that). Birk's mix is fairly acidic because of the moss. If you use sphag and orchiata for example, your media pH will be around 5 to 5.5 or something like that. With a pH of 8, you should be able to water freely for many months without worrying too much about pH. If you can use a fert with a Nitrate to Ammonium/Urea ratio of about 4 to1 you probably wont ever have to worry about adjusting pH before you repot again.
With the fertilizer strength, it totally depends on how many times you water in between feedings.
I'm guessing (and its a very rough guess) that 1/4 teaspoon in 10 Lt will give an EC of 0.3 to 0.5 dS/m. so don't go higher than that and better if you reduce it to 1/4 to 20 Lt every second watering. I have a bunch of Old Paph hybrids in that very mix which have only been fed 2 or 3 times since August and they look very good and still putting out healthy new leaves.
Also the older the mix, the more nutrients it holds and the less you need to apply.

 

[kiwi]

Cheers Mike. Yes we are extremely fortunate here in that we have some of the best drinking water in the world.

 

[Rick]

Your water is about the same as Nashville tap water.

You can use the fertilzer that you mention just use it sparingly.

I know of one very succesful grower in Nashville that went to strict use of Calcium nitrate for a year after a lifetime of use with a high K fertilizer (and saw some of his best results ever.

He has since made his own version of a low K fert and continues to see good results, but feeds at roughly 50ppm N weekly.

I feed at 5 or less ppmN almost daily.

But as Mike suggests, use a super week fert of what ever you have and apply once every other month will work good too.

 

[kiwi]

Thanks Rick,
I have now ordered K-Lite from Ray. With the water quality I have here what concentration would you suggest I add it to use every watering? Would this be the same for seedlings of 4 months?
Thanks again