Water analysis

[King_of_orchid_growing:)]

Oh, yeah, if any of you has the time, try plotting the points on a graph for the pH values throughout the course of three or four hours during the late afternoon/evening hours and you'll most likely see a dramatic change in pH...

[King_of_orchid_growing:)]

I forgot, if you tried the 3 or 4 hour thing, testing in 15 minute or 20 minute intervals should suffice.

[King_of_orchid_growing:)]

Okay, now for simple answer (thank goodness!), buying water from a water store is fine. If you have 2 orchids, shouldn't be a problem.

As far as pH as pertaining to orchid growing...don't sweat it too much unless you're growing terrestrials like Cypripediums or Disas. Even then, don't over do it.

[Corwin]

Again thanks for all that info it's pretty interesting (I didn't know the pH could change that fast)

I had a look on the web to see if any water analysis has been made for my tap water... they did one in 2008 (that's in german of course)

pH between 6.94 and 8.61.... So as long as the pH of my fertilizer solution somewhere between 5 and 7 it should be OK I guess

The GH looks ok too for my orchids (Phal and Dendro phal)

I'm going to boil the water to reduce the KH, or cut it with demineralized water (or both)

[Des]

Originally Posted by King_of_orchid_growing:)

A quick word on the pH of water. It fluctuates within a certain range on a daily basis. This has something to do with the oxygen and hydrogen ratios in water, and other factors.

And also the temperature, interesting thread thanks.

[Corwin]

Ok so the tests with boiled water

Water before :

KH = 6°d (107 ppm)
GH = 8°d (142 ppm)
pH = 7.2

Water after (cooled) :

KH = 6°d
GH = 8°d
pH = 7.2 no change at all... I suppose it should be boiled longer (I used a water boiler)

Water after (boiled for 15min then cooled)

KH = 6°dH
GH = 8°dH
pH = 7.2 again, no change... I guess you have to boil it a very long time... like 3 days . I think they meant 'distill" and not 'boil'

Water after + fertilizer (3-4-5 NPK Compo Orchideendünger @ 120 ppm)

KH = 6° dH
GH = 8° dH
pH = 6.8 after 15 min

Boiling the water does'nt really help at all, and the fertilizer reduces the pH. I suppose the effect would be more pronounced with a less alkaline water.

[Ray]

Read the stuff in the link Corwin posted, above. it's intended for aquaria, but does bring up "alkalinity", which is actually more important than just pH alone.

I have posted Bill Argo's 5-part series on plants nutrition, and the section on fertilizers brings it better into focus for us: Plant Nutrition

[Corwin]

Am I right in assuming that alkalinity is not a problem per se but determines the type of fertilizer you have to use?

(It's very interesting to try to find the correct mix... I didn't know it would be so complex )

[SueinNC]

I am wondering about my tap water.
The water plant keeps Hardness (mg/L CaCO3), between 15 and 16. The Alkalinity (mg/L CaCO3) is 20. The pH is 6.5, which I am figuring is ok since it is almost neutral.

[derv88]

I just did my first un-scientific water test with the following results. This was done using Quick Dip aquarium multi-test kit strips.

Nitrate - NO3 - 10 ppm
Nitrite - NO2 - 1 ppm
Total Hardiness - GH - 250 ppm
Total Chlorine - .5 ppm
Total Alkalinity - KH - 250 ppm
pH - 8.0

I ballparked the results due to the subjective comparison of to the color code reference chart.

Now the question is, are these safe ranges for catts, phals, brassavola, dends, a fredclarkera, an Aerangis, a Maxillaria off the top of my head?

---------- Post added at 05:56 PM ---------- Previous post was at 05:51 PM ----------

EDIT - I guess my real question is based on those test results, do I need to add a RO filter system to my budget for this year or is tap water sustainable for my crop listed above?