pH off the Charts

Savannah, GA

My soil is sandy and I've known for a while that the pH was probably out of whack. But I'm still a newbie and so haven't gotten around to doing anything about it.

This spring I did amend my soil with an inch or two of my compost and mushroom compost, and have mulched.

I tested the pH using a Ferry Morse tester (which I know are not very accurate), and the needle was off the chart (see photo). I chose a spot under my poor Confederate Rose, which always has yellow and spotty leaves. Then I tested again in my vegetable bed, and the reading was more or less in the "good" zone. I brought in all the soil for the bed, so that makes sense.

So, assuming the reading for the spot under the Confederate Rose is more or less accurate, do I do anything now, in the spring when I've already planted everything? Or should I do nothing, have the soil properly tested in the winter by Univ of GA, then treat it accordingly in the spring before I plant?

Thanks for your help.

Thumbnail by dedukes
Enterprise, AL(Zone 8b)

That may be a right reading but it doesn't sound right. Most soils in the Southeast are acid, and especially if they are sandy. Was that area next to a block wall or anything like that, anything you can see that might cause such a high ph reading. I would take several more trial testings all around the yard and garden. Your right, those meters are not very accurate, I have one very similar, all my readings have always been around seven or below. But at least your meter is showing a lot of variation from one spot to another, a sign I think, that the meter is actually reading something. I often wonder if mine is actually working at all.
With a ph reading that high I would think you would be very limited in the things that would grow at all, much less perform very well. If that reading is correct I would contact the county agent and see what they recommend doing and start right away!

Everett, WA(Zone 8a)

That low a reading, if true, "below zero"? would indicate a very strong acid. You mighnt double- check it aginst some pH paper or one of those soluble-caopsule test kits.

But if you believe it, how much could some lime hurt? Sandy soil isn't supposed to need much lime to get aq big chn age, but then maybe it didn't take mu ch of some acidic amendment to make it so acid, either!

>> do I do anything now, in the spring when I've already planted everything? Or should I do nothing, have the soil properly tested in the winter by Univ of GA, then treat it accordingly in the spring before I plant?

Lime is not very fast-acting, so I would buy a 50 pound bag extra-finely-ground dolomite lime and then sprinkle some on the surface ASAP. Scratch it in if you can. Try to avoid getting it on leaves, but spraying the foliage with water should flush it off.

How much? I don't know pounds-per-square yard. "Sandy soil" suggests "not much", but "pH zero" suggests ":use a lot".

I suggest a medium application, water, wait a few weeks, re-check the pH. Repeat every few weeks or 2 months until the pH starts dropping. Once you've got it moving, re-check and re-apply lime only every several months or twice per year so you don't overshoot.

If you can't scratch it into the soil, never add so much that the surface stays whiteish. It IS smart to defer heav y liming until you can turn it under and dilute it through the soil, but "pH zero" really ought to mean that it is killing things.

It's surprising the mere rain isn;t washing SOME of that ac id out! Even Coca-Cola and lemon juice only have a pH around p;H 2 or so. You need 1 molar Hydrochloric acid (36 grams / liter) to really get pH zero!

Once you're close, like pH 5, use a coarser lime and only add once per year. It might take a few years to sneak up gradually on the pH you want (5.5 ro 6.5??) and not overshoot.

>> I'm still a newbie

AVOID hydrated lime and quicklime! Those could burn plants, or your skin. Use agricultural lime. I olnly know about clay soil, but we always opreferred "Dolomite Lime", so that we got cxome Mg along with our Ca.

Enterprise, AL(Zone 8b)

Maybe I am reading the meter backward?

Everett, WA(Zone 8a)

I don't know, I just go by the numbers.

pH 0-2, acid.

pH 9, basic.


Enterprise, AL(Zone 8b)

I should have enlarged the picture so I could read the numbers, I see now. Reverse everything I said.

( Pam ) Portland, OR

This doesn't make sense. I wondered why deduces photo looked like that ... the tester says fertility not PH. So then I looked for a picture online. Check this out. Do click the enlarged image.

Since when was the ideal PH there ??? and 6.5 or 7 terrible. LOL
Too much ? Too little ? huh ?
What am I missing ?

This message was edited May 23, 2013 8:01 PM

Thumbnail by citybusgardener
Anne Arundel,, MD(Zone 7b)

I find it hard to think that meter is accurately saying the pH is below zero there. The plant would be toast.

Stick the meter in lemon juice and see what it says. Or vinegar.

I would regard that as suspect and use some lime to moderately try to adjust the soil, and see. Most of us in the East are used to begin told to lime even annually.

(Arlene) Southold, NY(Zone 7a)

I agree about testing the meter with vinegar or lemon juice before doing anything to the soil.

We have a few meters, none expensive, and I tested coffee grounds to show they are not acidic. Some meters measure light, pH, and moisture. My thought would be to buy a new meter instead of doing any potential damage by applying too much of anything to the good earth. Any Home Depot, Lowe's, or nurseries should have them or $12.00 or less.

Thumbnail by pirl Thumbnail by pirl Thumbnail by pirl
Savannah, GA

Thanks for all the great advice.

For the record, the top scale is the pH scale, the bottom one is Fertility. And yes, Seedfork, for pH scale goes 0 to 9, right to left.

I have a chemist friend who has a high end soil tester that he's gonna bring by this weekend.

Question about spreading lime: if I've mulched everything and I've already planted, I assume I somehow remove the mulch and then, um, somehow scratch the lime into the soil 4-6 inches below the surface?

Enterprise, AL(Zone 8b)

citybusgardener, I am so glad to see I am not the only bad meter reader, but the PH is the top scale "PH" written in the center of the meter at the very top. The word "ideal" applies to the PH reading above it, which is 6.5 to 7.
"The too little " , "ideal" and "too much" applies to the fertility rating on the lower scale. I am afraid my error might have contributed too your error!

Enterprise, AL(Zone 8b)

Did you follow the instructions:

Remove the top 2" of the soil surface. Break up and crumble the soil underneath to a depth of 6". Remove any stones or organic debris such as leaves and twigs because they can affect the final result.
Thoroughly wet the soil with water (ideally rain or distilled water) to a mud consistency.
Slide selector switch to the right which is the position of pH to measure the acidity and alkalinity of the soil. Slide selector switch to the left which is the position of fertility to measure soil fertility.
Clean probes thoroughly and insert them into soil up to the specified base. Wait one to two minutes and take reading.
Or did you just stick the probes in the ground and then read it?

Everett, WA(Zone 8a)

>> Slide selector switch to the right which is the position of pH to measure the acidity and alkalinity of the soil. Slide selector switch to the left which is the position of fertility to measure soil fertility.

THAT must be it.

Probably you had the selctor switch on "ferility" and it was telling you that you used much too much fertilizer.

Or the switch is bad and you got some kind of circuit error meaning nothing. Cheap mechanical switches are often the first thin gs to fail.

Since the pH is 6.5, add no lime for nows. Slightly acid is where many nutrients are most soluble.

Stop adding fertilizer until many leaves go from dark green to light green (or yellow-green). If the "fertility" readin g is still very high after a rainshower or heavy waterings, maybe consider using enoguh water to fluish some of the excess fertilizer away from the roots.

Or ...

The "fertility" probe may be simple conductivity, and it may be reprting salts (like Sodium and Chloride) as if they were Nitrate, Phosphate or Potassium. If it is meauring salt, you might have salinity buildup instead of exc ess NPK (or in addition to NPK).

What do you water with? Brakish or bad-tasting water? Do you have a high water table of brackish water?

Never use the output from a "water softener" to water plants! Most of them exchange road salt (NaCl) for the "hard" minerals.

I've been told that "Hard" water is not a major contributor to salinity, I guess because Ca and Mg are not that solub le ... but I don't really know.

Has your sand spent a lot of time being under-watered? For example if it seldom gets a real heavy FLUSHING, even minor sources of salt could build up over years. Fertilizer, manure, seaweed, salty sea breeze ...

( Pam ) Portland, OR


Not your fault .. I loose the plot sometimes and never needed any help. :)


The data available on Starbucks site covers the PH of coffee grounds if you want some reading for a rainy break. I found it very interesting.
I wasn't aware they had multi-testers with a light meter. I've always walked past that section of the nurseries since a few decades ago I was taught all moisture/ph meters are junk. You have now sent me to Amazon, reading the reviews. It's all your fault. LOL


The reviews are a real trip. I sort of get the feeling most of it is doing the tests correctly. Several different posts that seem reasonable, explain HOW to properly use the testers.


I think your thinking in the right direction on how the fertility tester works. That one is what really peaked my curiosity. This thread of reviews has a couple good posts.

ETA ... wrong thread but that one does have directions on how to use the tester correctly. Lost the one I thought I linked to.. sorry.

I think my being closed minded needs to change. Wonder what my local garden shops have tomorrow ? It's one of those weekends when they really need the business. What a shame.. I may have to go to the plant store. ;)

This message was edited May 24, 2013 8:57 PM

(Arlene) Southold, NY(Zone 7a)

citybusgardener - I view the meters as a general guide to pH and not a substitute for a soil test, which would give the actual fertility and you'd be advised of the nutrients that are excessive or below that which is required. The coffee grounds are excellent when mixed with the soil and help retain moisture. If they are placed directly on top of the soil and not mixed in, they form a crust - not good. We rely heavily on our own compost and have four bins going now, two bins with items that will be chipped in the fall to make more compost along with the dried leaves, grass, household vegetative waste.

I'll take the blame - LOL. I don't rely on the light meter since most gardeners know full sun from shade and which plants are happiest in shade or sun.

Savannah, GA

Thanks for all the great feedback, folks. And yes, I did follow the instructions. But I'm about to go try coffee ground and another part of my garden right now.

( Pam ) Portland, OR

Not to worry Pirl, I won't be altering my soil based on a piece of plastic and wires. I listen to the weeds. Depending on what springs up in any particular spot in the garden and does well there, I have a pretty good idea what the soil is doing. I'm a weed-whisper. LOL For my own weeds, not other parts of the world. I did soil testing every few years back in the beginning and will again if I run into the need.

Compost ... my composting is self defense due to the mass quantities of leaves and plant material my garden produces here in the city. While I do send a lot out in yard debris every week, since composting all of it I would have no room to garden. By putting back on the land what it has produced, there's no need to purchase stuff that would have to be hauled in my granny cart on the bus, just to get it here. Dang, that would be a full time job all by itself.

Coffee grounds. I give the kitchen scraps and coffee grounds to whichever bin/pile has the biggest active worm explosion at the time. Brand new piles are too hot for the little guys and old piles don't have enough good stuff to house and feed them. These worms are my little buddies trying to help me deal with all this yard debris so coffee treats it is for them. They deserve it, they work hard.

Easy for you to say "most gardeners know full sun from shade and which plants are happiest in shade or sun" I've seen your beautiful pictures of your garden with all that sunshine. Here I'm in my own little forest. So my desire is to more easily know the difference between shade, part shade, bright shade, lite shade, filtered shade, etc. compared to each plants recommendation. Dense shade is pretty easy..everything dies or lays down towards the light it knows is out there. . This has always been my biggest head scratcher. " How much shade can you take and still thrive ?". If I had a number from the meter, I could then be more accurate in my guesses over time.

I'm thinking maybe playing with one of these multi-meters, and adding the results to what I already know, based on just over 40 years with my piece of land, could add one more way to potentially figure out those little garden mysteries we all accumulate over time. If nothing else I will finally settle the curiosity of reading about these and what that group of things hanging on cards over in the seed starting/winter protection stuff part of all the garden stores. And you know what they say about curiosity.

(Arlene) Southold, NY(Zone 7a)

Weed whisperer! I love it.

We have to take some of our yard waste to the dump. We tried composting weeds and felt it wasn't worth the risk. Considering all the compost we have and all that's working in the bins, there's no way we could add the 100 plus bags that my husband took to the dump since February. It's a good feeling to use the compost we've made.

In one garden I added a lot of coffee grounds over one winter and couldn't believe the huge amount of worms by the spring. What causes them to gravitate to the coffee grounds? Much of my gardening is "worm relocation" so if I'm digging to add a plant and spot worms I do move them nearby but don't want to put them in the same hole as the plant or they'll have to scurry to avoid the water I add for the new plant.

Thank you for the compliment. Degrees of shade aren't so easy to judge. Dead shade (the shade of a house/shed/garage) was the most difficult one for me but I've got it done and it's staying as is. I do laugh when people say they put an astilbe or a hydrangea in shade "that only gets sun from noon to 3 PM". That's not my idea of shade! Many plants are more tolerant than we think and can take a touch more shade. I'd rather go that route than too much sun. And then there are those plant tags that aren't exactly helpful when they say part sun to shade.

To complicate sun/shade matters even more, there's sun in the northeast compared to sun in the hottest zones, same with shade.

Gardening can challenge us.

Thumbnail by pirl
( Pam ) Portland, OR

That's really bright shade in my in the city forest. But I know exactly what you mean when reading other peoples shade posts. They are 99% useless compared to my cave-like situation. :)

Worms... Yes, they sure seem to like the fungus that forms near old used coffee grounds. Resulting in happy, well fed worms having the sexytimes and you get more worms !

Weeds... Judge them as individuals. Many bring up nutrients that our gardens benefit from, so tossing all of them creates the need to purchase things that hopefully are adequate replacements. Weeds also attract and harbor many of the beneficial insects that help us. I'll add a good link for those interested

Well, no new tester for me this time around. I'll keep my eye out, but the $22 Amazon 4 type tester was a full $40 at the garden shop. I planned on more, but not that much more ya know. Turns out I'm not quite that curious, so came home with an alternate purchase that I'm super happy with. I'll meet you in the clem forum Pirl.

This message was edited May 28, 2013 3:08 PM

Enterprise, AL(Zone 8b)


Any new update on the pH readings?

Post a Reply to this Thread

Please or register to post.

Upload Images to your reply

    You may upload up to 5 images