Amazing New Fertilizer

[ronaldhanko]

Originally Posted by ALToronto

Ron, the higher pH that you would see with K-lite could also have played a role in the improvement you saw. Live sphagnum is very acidic, and conventional fertilizers also drop the pH of water, sometimes considerably. So you could have been growing your plants in a pH of 4 or thereabouts. This is too low for most plants, and the nutrients in the fertilizer solution also become less available to the roots (but they stay in the moss).

pH and TDS meters are about $15 each on amazon; there is really no excuse not to have them.

That's a possibility, Al.

[Jayfar]

Originally Posted by ALToronto

pH and TDS meters are about $15 each on amazon; there is really no excuse not to have them.

Thanks for bringing that up. Not to go off-topic, but I've recently realized I need to get more serious about knowing what's going on in my potting media as far as pH, TDS and EC. My tap water was lab-tested at pH 7.06, alkalinity 55.2 and SS soluble salts (mmhos/cm) 0.38, but I understand my fertilizer and stuff going on in the potting media may bring the pH down to a better range.

Are the lower-priced meters worth bothering with? Is litmus paper useful instead of a pH meter (I see repotme sells litmus strips for 4.5 to 7.5 range, although I can't seem to find the one they sell on Hydrion's own site).

Recommendations for a mid-priced combo meter?

[DavidCampen]

I have Hydrion 4.5-7.5 pH paper, the accompanying color chart is in divisions of 0.5 pH unit - 4.5 5.0 5.5 6.0 6.5 7.0 7.5. With this you can get to within +- 0.5 pH unit. So, for example, I can tell that a solution is somewhere between pH 5 and pH 6.

I also have Hydrion Microfine pH 4.5-6.1 that has color chart divisions of 4.5 4.7 5.0 5.3 5.5 5.8 6.1 and Microfine 4.9-6.9 with divisions of 4.9 5.1 5.4 5.7 6.0 6.3 6.6 6.9

By using all 3 I can estimate the pH to within 1/2 unit so I can tell if the pH of a solution is between 5.0 and 5.5 or 5.5 and 6.0.

I bought all of this from Amazon. I also have a few other ranges of pH papers. For what I spent on pH papers I likely could have bought an inepensive pH meter but the pH meter has to be stored with the probe tip kept wet and should be calibrated frequently.

I use a Hannah Instruments TDS meter. If I bought one again I would get one that reads directly in conductivity instead of TDS.

[ALToronto]

I use my pH meter every day, so the tip is always wet. Just make sure you rinse it in pure water before you put the cap back on. Or you can keep it in a glass of pure water and change the water daily.

However, the first time I used the meter, after it arrived, the tip was bone dry, and when I tested store bought distilled water, it read 7.0.

Municipal water pH fluctuates by several decimal points.

[DavidCampen]

Originally Posted by ALToronto

I use my pH meter every day, so the tip is always wet. Just make sure you rinse it in pure water before you put the cap back on. Or you can keep it in a glass of pure water and change the water daily.

What make and model are you using and if you were to buy a new one would you look for something different?

[ALToronto]

Originally Posted by DavidCampen

What make and model are you using and if you were to buy a new one would you look for something different?

This is the meter I bought, accurate to 0.1:

Amazon.com: Mini Digital Pen Type PH Meter PH-009 I Multimeter Tester Hydro: Electronics

If you don't want a case or the little adjustment screwdriver, you can pick one up for under $10. The manufacturer is Neewer, and the same meter is sold under a multitude of private labels. I'm perfectly happy with it, but if I had to replace it, I might look for an all-in-one pH, TDS and EC meter.

Back in the early 1990's, when I first started growing orchids, the same meter cost $120. A TDS meter was over $300, and I couldn't justify buying it. If anything, the accuracy is better now, for 1/10th or less of the cost.

[Jayfar]

Originally Posted by ALToronto

This is the meter I bought, accurate to 0.1:

Amazon.com: Mini Digital Pen Type PH Meter PH-009 I Multimeter Tester Hydro: Electronics

If you don't want a case or the little adjustment screwdriver, you can pick one up for under $10. The manufacturer is Neewer, and the same meter is sold under a multitude of private labels. I'm perfectly happy with it, but if I had to replace it, I might look for an all-in-one pH, TDS and EC meter.

Back in the early 1990's, when I first started growing orchids, the same meter cost $120. A TDS meter was over $300, and I couldn't justify buying it. If anything, the accuracy is better now, for 1/10th or less of the cost.

I just ordered these on amazon:

HM Digital TDS-3 Handheld TDS Meter

HM Digital PH-80 pH HydroTester

HM Digital PH-STOR pH Electrode Storage Solution

Atlas Scientific pH 7.0 Calibration Solution

I'll need to eventually get the calibration solution for the TDS meter too, but the factory calibration is supposedly good for up to a year.

The HM meters seem to get generally good reviews and the documentation on their website is pretty decent.

WATER TESTING INSTRUMENTS - HM Digital

EDIT: I subsequently changed my mind and ordered the HM pH-200 model instead. Unlike the pH-80, its probe is replaceable and I understand the probes may only last a year or two. So the pH-80 is essentially disposable.

I won't have time to play with my new toys till at least next week though.

[Discus]

I've had a Hanna pH & EC meter for a couple of years, and I quite like it.

Orchids on a Balcony: New Gadget: Combo pH & EC meter

Orchids on a Balcony: Calibrating a Hanna HI 98129

[DavidCampen]

Originally Posted by Ray

Yes, potassium is abundant in nature, but not in throughfall or stem flow, which is where epiphytes get the majority of their nutrition.

Here is a study showing that potassium is more abundant than nitrogen in stemflow and throughfall in a forest in Borneo.
Slippertalk Orchid Forum- The best slipper orchid forum for paph, phrag and other lady slipper orchid discussion! - View Single Post - K-lit after 6 months

I had presented this study earlier in a thread at SlipperTalk and the defenders of K-Lite thoroughly discounted it because of various perceived flaws.

Now that the author of the AOS article presents it as somehow being evidence of his nutrient toxicity thesis (whatever that thesis exactly is, it keeps shifting) it is accepted without comment.

[DavidCampen]

I see that Jack Peters of JR Peters company has a letter published in the June, 2013 issue of AOS Orchids. The title of the letter is "Value of Potassium". He begins the letter by saying "I read with interest Rick Lockwood's article 'What do Orchids Eat'. While there are some interesting observations made and opinions expressed I feel that the overall impression from the highlighted subtitle, 'Are Your Orchids Addicted to Potassium?' may be somewhat misleading to many of your readers." He concludes by saying "I would urge the loyal readers of Orchids to read more about plant nutrition and the role of all essential elements to better understand and put Lockwood's article in proper perspective when making their decisions regarding their orchids nutritional regimen."

While he is much more circumspect in his criticism of this article than I have been, it is still gratifying to see this in print.