BEST PH LEVEL OF WATER FOR ORCHIDS

[zynah]

Which is the better Ph level of water for orchids,Some one suggest the Ph level in between 6 to 6.5 is good.What is the benefits.

[lepetitmartien]

Each nutrient has an absorption window by plants, it's not the same for all elements. The best zone is around there.

There's a paper at Ray's site with a clear graph: pH & Nutrient Availabilty

[RosieC]

Moved to Scientific matters.

[Ray]

Originally Posted by lepetitmartien

Each nutrient has an absorption window by plants, it's not the same for all elements. The best zone is around there.

There's a paper at Ray's site with a clear graph: pH & Nutrient Availabilty

Actually, if you read the entire article, and not just look at the graph, you'll understand that the graph was experimental data from a single soil pour-through study.

Soils have a great many sites (edges of clay particles and fine organic matter) that can trap nutrient cations - the Cation Exchange Capacity (CEC) - and that can vary drastically with pH.

Orchid media, by contrast, have little-to-no CEC, so basically, if it is in solution, it is available for the plant to capture and take up.

While there is likely to be some variation among plants, I think that staying in the 5.5-6.5 range is fine, and if you stray outside of that a little, it should present no problem.

[Leafmite]

I agree with Ray but whatever medium you use for your orchids can sometimes influence the pH.

[NYCorchidman]

What orchids are you talking about?

Some have distinct range, but I read that most will be fine around the range of late 6 to early 7.

[OCRC_Dir_China]

The complexity of water quality as a subject is reflected in the many types of measurements of water quality indicators. The most accurate measurements of water quality; are made on-site, because water exists in equilibrium with its surroundings.
Measurements commonly made on-site and in direct contact with the water source in question include temperature, pH, dissolved oxygen, conductivity, oxygen reduction potential (ORP), turbidity, and Secchi disk depth.

[lepetitmartien]

I had read it Ray, a looooong time ago. But also I've never seen something contradicting it for epiphytic orchids.

Those who did studies on nutrients available in streaming water up in the trees where orchids walk and sing in the morning must have made measures of pH too. The road to follow… 'intelligent guess'

[Ray]

Originally Posted by lepetitmartien

I had read it Ray, a looooong time ago. But also I've never seen something contradicting it for epiphytic orchids.

Probably because nobody has ever truly evaluated it for epiphytes (or terrestrial plants since that study), but takes it as "gospel".

Speaking to a developer of MSU fertilizer yesterday, he reminded me that essentially all of the plant nutrient studies done have been with dicots, not monocots. That leaves orchids essentially with zero data.

Even our own work with K-Lite isn't really a nutrient study, it is a test of "does it work". Nothing more.

[lepetitmartien]

And if they did not measure pH while measuring nutrients they missed part of the picture…