Richard

Took my pH meter off the shelf today and noticed it was ready 4.2, not 7.0 as expected. Hmm. So I cleaned all the oxidation off the contacts down to shiny metal and stuck it in a box of lime for an hour. It's still reading 4.2, but in the garbage bin. I guess for $10, lasting 7 years wasn't too bad.

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MediaHound

Just recently put a new electrode on my pH controller on my reef

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bencelest

Talking about the pH meter. I got mine out because I have 3 citrus planted on the ground whose leaves are very yellow all the leaves. I thought it was nitrogen difficiency but when I sampled the soil, the soil were very acid 5.2, 5.4, 4.9.
Naturally I bought some prilled dolomite lime at garden store and add it into the soil. I'll check the pH and the leaves every 4 days or so if there is any improvement.
The tempt maybe a factor also since we just got over the winter. But I'll keep an eye on them.

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chong

I always thought that yellowing of the leaves was caused by Iron and/or Nitrogen deficiency. My plants used to have that tendency. A regular regimen of "Ironite" usually cured the yellowing. If you're using a lot of wood chip mulch, it could be taking up a lot of the nitrogen from your soil, too.

Or, it might be caused by your water supply, too. Especially, if you have a water softener for your entire house supply system.

I would have your pH meter checked for accuracy before adding Lime to your soil. Yellowing of the leaves will be aggravated if you add more lime to neutralize the acidity. More nurserymen will recommend making your soil more acid when you have yellowing of the leaves of your tree. The will recommend using "Miracid" to get your leaves to turn green. Since your pH readings are showing an over acidity in your soil, but then your leaves are yellowing, this leads me to believe that your pH meter may need to be recalibrated, because the readings contradict the symptoms of your plant. (If your meter can be recalibrated.) One thing you could do is check the your tap water with your meter and see if your meter will read it as in the neutral range.

chong

Benny,
I just thought you might want to read this article that talks about citrus leaves yellowing. I sure hope that your tree does not have foot rot, the third cause of yellowing leaves in citrus.

Summer Ailments of Citrus Trees

bencelest

Chong : Everything that you said is true- the symptoms and effect to the plants.
But I trust my meter. I have PHH-715 Mini-pH Meter.
I bought that years ago.And it is accurate up to .02 of a point. I have a buffer solution pH4.00 and 7.00 and I calibrate the meter before I use it.
It is true that the symptoms you describe yellowing of leaves is due to iron or nitrogen difficiiency provided that the pH is at the norm but things will turn helter skelter if your pH is too low or too high because there are some nutrients not available to plants in either way. Your plants will be just like a baby with her mouth close so no matter how much you feed her she will still be hungry because nothing gets into her tummy.
Here's some excerpts from 'Understanding pH Management":
5. Soil pH affects the amount of nutrients that are
6. soluble in soil water and, therefore, the amount of
7. nutrient available to plants. Some nutrients are more
8. available under acid conditions while others are
9. more available under alkaline conditions. However,
10. most mineral nutrients are readily available to plants
11. when soil pH is near neutral.
12.
13. The development of strongly acidic soils (pH less
14. than 5.5) can result in poor plant growth as a result
15. of one or more of the following factors: low pH,
16. aluminium toxicity, manganese toxicity, calcium
17. deficiency, magnesium deficiency, and low levels
18. of essential plant nutrients such as phosphorus
19. and molybdenum.

Nitrogen (N)
uptake can be indirectly affected by medium pH
because low pH decreases nitrification (conversion of
ammoniacal nitrogen to nitrate nitrogen) or the
conversion of urea to ammoniacal nitrogen.
Some species will
perform better when grown at a low pH, some will
perform better when grown at a high pH, and for some,
it will not matter. However, for each of these groups,
the acceptable range where they will grow and perform
the best will be relatively narrow and will be similar
that of other plant species. If you had to choose a pH
range to grow, then the recommended range
would 5.8 to 6.2,
So whatever the case maybe, I will have to correct my soil pH to near neutral before I do anything.
And normally, when I have a reading near normal pH my plants return to normal.
You ought to see my citrus how nice and green looking they are and what I normally do is watch my soil pH. I can not overemphasize this.
Many people have the wrong notion that if your plants are yellowing, add ironite or fertilize the plant high on nitrogen. I totally disagree.
It should be : correct your soil pH first before you do anything.

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chong

Okay, Benny - that's great. Unfortunately, your quoted excerpt does not show up on the actual post, but I was able to read it below the reply box while I was typing my reply and was verifying what you wrote. The first paragraph had some weird numbering system(from 5 to 19) at the beginning of each line, and they seemed unrelated to the paragraph. Anyway, I was able to read it. It appears that your meter has the feature to be calibrated. Does your meter require that you mix equal parts of water and soil in a bucket, or stick it directly into the soil?

I don't think it's wrong to assume that adding Iron and/or Nitrogen as a cure when your citrus leaves are yellowing because that's what most references will advocate. And in my experience, that appears to be so. Yes, adjustment of pH to an optimum level is important to the health of the plant. But from what I read, low pH affects the growth of the plant, but seldom is the result manifested by the yellowing of the leaves. Low soil pH often results in a plant that looks healthy and green but slow to grow and produce little fruit, if at all. I've haven't heard it resulting in yellowing of the leaves.

Now that you've gotten me to look at pH levels. It just occurred to me that my Philippine Magnolias are very slow growing and seldom bloom. Hmmmm, I have to check their soil pH. My Michelias (see avatar) are doing great, but one of the bigger plants' leaves were yellowing last month. I applied some Miracid and it is now on the green side. It looked like pale sunflower yellow before.

Out of curiosity, what is the pH of your tap water? In a lot of places in CA that I've stayed in, the water is so soft that it was difficult to get rid of soap suds/film when washing or taking a shower.

bencelest

Sorry. When I copy and paste those excerpt's, I can't get rid of the numbers and it was about 1 AM so I just let it.
You are so right with everything you say. Before I have that meter, I follow the authors'recommendations and usually they are the same with what you said and my plants are lush and green also.
But since millet sent me that pamphlet "Understanding PH Management" I changed my ways of doing things. I always now check the soil pH before I correct other things.
So I am just like a mechanic or electrician, I have the meters to use so why not use it? Like refinement of solving your problem.
I don't want to go blind with what I am doing. I want to see like an extra eye.
You are an engineer so you understand.

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bencelest

The meter will tell you to take 3 samples at about 6 inches deep at 3 different places in your pot or garden. Put them in a clean glass and add either distilled water or the water purified by osmosis. Stir the soil until it is at pancake consistency.Wait one hour before you take a reading.
As for me I just wait 5 minutes and I take a reading. I found out that there is only a difference of less than .5 in readings.
My tap water here is 7.6 I believe.
The optimum pH for citrus is 6.5 BTW.
PS
From my experience the tendency of my plant's soil pH either in pots and on the ground is very low pH now that I think about it. There are only a few times that some pots have high pH. Either way, the plant will tell you its dissatisfaction.
Once I corrected the problem they became happy and they will show it to you too.
As a precaution remember it may take many months before it shows .

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chong

Wow! 7.6 pH water supply. Have you actually tested it, just for accuracy sake? That could be contributing your yellowing leaves. Although, I've read in certain areas, that citrus can tolerate pH as high as 7.0, so I'm not sure that that's a factor here. But coupled with exposure to cold temperatures and winds, it would at least make it suspect. From what I've read, the ideal range is pH of 5.0 to 7.0, with the optimum at 6.0 to 6.5, as you stated.

I mentioned my Philippine Magnolias do not grow very well,even compared to Michelia. Your protocol of testing the soil pH led me to think about checking their pH requirements because the Magnolias and Michelias belong to the same family (In fact, the International Magnolia Society recently renamed the Michelia as Magnolia in spite of the distinct growth and blooming characteristics.) I was puzzled why, despite the same treatment, in terms of temperature, lighting, fertilizing, and watering, the Michelias are more vigorous growing and more productive, but the Magnolias are slow and barely bloom. They both came from the same region in China.

I had misplaced my pH meter from a long time ago and now in a hunt for a good pH meter. Most of the garden shops here only carry an inexpensive one made by LusterLeaf "Rapitest". Do any of y'all have one of these, and are they reasonably good? Thanks for any feedback.

bencelest

My first pH meter is the cheapo kind that's worth $12 I bought at a nursery store. Never again will I buy another one like that. They are very inaccurate. It appears to have a mind of its own. When you measure your soil pH and then measure it again there are sometimes a difference of 3 to 5 times difference. And to think that the difference how acid or alkaline a soil is that from a reading of let's say from 7.1 to 8.1 that is a difference of 1.0 the soil is 100 times more acidic or more alkaline.
So what I did to mine was throw it as far away as I can to my next door neighbor.
If you are serious growing things in your yard invest on something really accurate meter. But it is not cheap. Mine cost $89.00 plus the buffer solution at $5 each for calibration.
I am very happy with mine. It's 4 years old now.
Here's the address:
OMEGA Engineering Inc
One Omega Dr
Box 4047
Stamford CT 06907
Cust. Service: 1-800-622-2378
203-359-1660; 203-359-7694
FAX: 203-359-7770PH Tester
Operation of the PHH-715 Mini-pH Meter

1. Flip power (toggle switch) on. If there is no display plug in a 9-12V DC + tip adapter to charge battery.
2. Units maybe run on battery or 9-12 VDC + tip adapter.
3. Connect a pH probe to the BNC connector and place probe in pH7 buffer to check calibration. If needed loosen the lock nut on the calibration pot and slowly turn the slotted shaft with a small screwdriver until the reading is correct. Check in pH4 buffer for pH4 +/- 0.02. If needed insert an alignment tool or small screwdriver into the hole on the bottom to adjust the slope to pH4.
4. If unit will not get closer than .02 pH call to get technical assistance, about internal adjustments or an authorization number for sending unit back for repair or calibration.
5. The probe can be hooked up to RG-58 or RG 62 coax cable up to 100 ft long.
6. If the battery will no longer take or hold a charge, open the unit and replace the battery. Bttery must be a Nicad or Metal Hydride rechargeable. Do not use an alkaline battery.
I did not buy the battery hook up. I just plug mine to a 110volt outlet. Less problem.

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bencelest

But if I have to buy a new one right now I'd probably buy one of these because it monitors nutrients you are giving them and monitors pH continosly

HANNA GroCheck Combo Meter - pH & TDS Meter
This is one of our favorite meters. It allows you to measure both pH and TDS (EC) at the same time, while conveniently hanging on the wall above your nutrient. The two professional quality probes are continually submerged in solution so that they have a real-time readout, without preparation or having to wait.

Although the Grocheck Combo Meter is a bit more expensive than other meters, the replaceable electrode on the probe allows for meter maintenance instead of meter replacement. Eventually it will pay for itself. Made by Hanna Instruments.

HI 981404N is ideal for agricultural, horticultural and hydroponics applications where pH and TDS levels need to be continuously monitored for optimal plantgrowth. HI 981404N continuously monitors and displays the pH and TDS values of a solution on an easy to read set of dual LCD's.

The HI 1286 gel filled pH electrode is replaceable and the BNC connector is protected behind a waterproof sheath. The unique design of the electrode guarantees greater clogging resistance in fertilizer solutions with high concentrations of phosphate, nitrate, etc.

TDS measurements are performed using the 4-4-2 conversion factor of 0.7 so you do not need to convert the readings. Equipped with a grounding bar to ensure more accurate pH measurements and longer electrode life. The HI 981404N is compact and easy to install and use. This makes it ideal for all continuous monitoring applications.

HI 981404N is supplied complete with HI 1286 pH electrode, HI 7634 TDS probe, HI 1283 grounding bar, pH and TDS calibration solutions (20 mL each), screwdriver, 12 Vdc adapter and instructions.
• Range 0.0 to14.0 pH; 0 to 1990 mg/L (ppm)
• Resolution 0.1 pH; 10 mg/L (ppm)
• Accuracy (@20°C/68°F) ±0.2 pH; ±2% F.S.
• Calibration Manual at 1 or 2 points (pH); manual at 1 point (TDS)
• Setpoint pH, adjustable from 3.0 to 7.0 pH; TDS, adjustable from 500 to 1600 mg/L (ppm) Alarm 2 LED's (1 each for pH and TDS)
• Temp. Compensation Automatic from 5 to 50°C (41 to 122°F) (TDS only)
• TDS Conversion Factor 0.7 ppm = 1 µS/cm
• Probe HI 1286 interchangeable pH electrode, HI 7634 TDS probe (fixed), HI 1283 grounding bar with 1 m (3.3') cable (included)
• Battery Type / Life 12VDC adapter (included)
• Dimensions 165 x 110 x 35 mm (6.5 x 4.3 x 1.3")
• Weight 300 g (10.6 oz.)
Product ID: HI981404N Category: pH and Nutrient- pH and Nutrient Monitoring and Control
Price: $169.95
Sale Price: $117.95
Savings: $52.00

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Richard

I bought an inexpensive one 7 years ago and had good service through last fall. It's a plastic meter with a small diameter metal rod to insert in the soil. It is a magnometer variety, so no batteries are required. They currently sell for $10-$15 at nurseries. I have tested mine for accuracy against other measurement systems and found it was accurate to the printed lines, about 0.1 pH. As Benny points out, you need to check several locations around the plant and discard any anomalous readings from contact with a rock, "hot" piece of bark, etc.

Here's a picture of one brand, the probe is twice as long as pictured, about 10 to 12 inches.

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sandy0225

The hanna instruments one is a good one, but be sure and get storage solution for it. Mine dried out and I had to put a new tip on it. Bummer!

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Northern Tropics Greenhouse
1501 East Fuson Road
Muncie, IN 47302
www.northerntropics.com


specializing in bananas, heirloom tomatoes and water gardening plants~
check out our new online store at our website!

chong

Thank you Benny, Richard, and Sandy. That's quite a wide variation in quality and price.

I've checked the Omega 715 and the current price is $92 w/ batteries, and A/C power adapter, and 1 more item that I forget just now. It appears that this is not recommended for water. Otherwise, it is very ideal. I just need to be able to check our water supply every now and then.

The nursery variety is anywhere from $9 to $16, but with shipping it would go for less than $25. The $9 one is available in a local nursery. Richard, is this "good enough for government work"?

Sandy, there are tons of Hanna pH testers. Which model do you have experience in?

Thanks again for your feedback.

chong

Oops! Sorry Sandy, it appear that I was responding at the same time that Benny was. So, is the Hanna Model HI 981404N the one you are referring to?

Thank you.

Richard

Yes, works great for testing soil up to 10" deep around a plant, or the root zone of a lawn, etc. Not recommended for aqua culture.

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chong

Thanks, Richard,
I think that for a $9 investment for the time being, I can use that for mostly potted plants anyway, until later on in the summer when I prepare the beds for my bananas that have been in captivity until now. I just wanted to get a feel from you whether it can give reasonable readings, with strict adherence to manufacturer's directions. I don't mind if it's off by 20%.

Perhaps the Omega meter would be the most practical, though I have reservations because I might need something for hydroponics application, which the Hanna meter may be a better choice.

I found a source on the net for the Hanna for $112! But for right now, it may be a bit of an overkill.

bencelest

Chong:
I don't understand when you said that the meter is not recommended for water.
I use the meter all the time to check the pH of my tap water, water/ sulfuric acid solutions to water my plants with.
Here's what I do to water my plants: I put the recommended fertilizer on an empty whiskey barrel then I filled the barrel with water. I mixed them with a paddle. After calibrating my meter I check for pH which is normally on the alkaline side. Then I add sulfuric acid a little at a time until the water reads 6.50 the optimum pH recommended for citrus.
I have a self-priming pump connected to a regular water hose to water my citrus.
Easy.
I may have to do a little bit different with my bananas now that I have them.

All you have to do is immersed the tip of your probe in water being tested or you can immersed the whole probe and cable if you want to. It's all waterproof.
To test the water supply: all you need is a glass. Get a sample from your water supply and immersed your probe there. No problem.

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Richard

I'll bet if you travel over to Jarred's other site for aquariums, you'll find a thriving conversation on inexpensive pH meters for that application.

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