What is is the readings supposed to prove?

Well, it could signify you have this thing about always wanting to know about a little bit of soil.
But for what reason?

Three months down the road what have you done to your soil that would encourage you to think you've changed it where plants have been affected.

Six months......two years....ten years...
have you done something to change matters?

This need to know ....no offence meant....but it harbors on being ---"sophophobia".....fear of not knowing

I suggest you forget about doing it.....because that could border on an obsession to want to fix it if a reading was to change from one day to the next.

I think its safe to say that the average American gardener....has his/her soil tested.....
...less than once in a lifetime.
I think most folks believe a plant will grow they put into the ground....and if it can grow one plant, it'll grow another....and another..
and no soil test is going to change it.

Raspberryflyer,

I will be more polite and diplomatic in my answer...

I just bought a PH meter for my daughter who is doing a science project concerning the acidity of soil. It's not an expensive model ($15.00 Canadian) and we were told it may not be accurate, but so far it's giving the readings which I expected. Dipped in vinegar which is highly acidic, the meter registers in the deep of the lower PH levels, and dipped in mucky ashes from the wood stove, the meter goes straight to the higher PH levels.

So far we've tested potting soil, forest soil, garden soil, lawn soil, etc. and the readings are what I expected them to be. It appears to be working well.

It's a simple meter with two prongs which are inserted into the muddy soil. In essence, you place the soil in a bottle, add water to make it muddy, then insert the meter and wait about 60 seconds. We kept the receipt just in case it didn't work, so you might want to do the same. It was bought at a garden center.

Since the ground has started to freeze here, we were out on Sunday with a pick axe digging. You have to get soil from about 5 inches down.

I am actually glad she chose this as her project this year. I have been wanting to buy such a meter for some time, and this gave me the right excuse. I have places on the property where blueberries grow and so I wish to keep the acidity at a high level. In the ornamental gardens, I'm looking for neutral soil. This meter will help me in achieving these goals.

I truly hope I've helped in answering your question, and that you will not be discouraged from posting at this forum in the future due to the above response. Most folks here are kind in nature and quite helpful and do actually focus on the question at hand.

Sincerely,
Nicole.

One thing worth pointing out when you're testing pH is that you should use distilled water for the test, because the pH of tap water can affect the results.

They are all junk and can't be relied upon.

Sometimes you get lucky and the calibration is spot on when new, but it isn't likely to last long.

Higher quality units have replaceable probes and these probes require special care to keep in working order. Even so they must be replaced every year or two to continue getting accurate results.

They also come with test solutions and the ability to calibrate the unit with these solutions so you know it is accurate before testing.

A bit more reliable are the test kits using chemical reactions and color indicators. They won't tell you anything more than pH in .5 increments, but that is good enough for home garden uses.

Many of these units come with light meters that are also worthless, nutrient level meters that just say 'low,medium or high' with no breakdown of what nutrients are acutally present or in what amounts and my favorite, the moisture meter that reads dry in distilled water because it doesn't measure moisture, but electrical conductivity.

I am not telling you to avoid them, but trying to convey their limitations.

I have a unit that does all the above (poorly) and since I know my soil is around 6.8pH I thought it was accurate when I tested my soil and it said almost neutral. Then I tested other things where I knew the approximate pH and it still said almost neutral. It basically says everything is almost neutral.

The best you can hope for with an inexpensive pH meter is that it works well for the first year or so.

Many people that did spend money on pH meters found that mostly they will read the pH of such divergent materials as vinegar or a mix of baking soda as the same thing. Mostly they are a waste of time and money.
Reading your soil pH right after adding some material is a useless ecercise since that soils pH will not be affected by that addition for quite some time afterwards. It takes months for a soils pH to change.

FYI, FWIW etc.

For a few there may be a cheap source of pH meters out there.

I met this woman who has something to do with the administration of a sewage treatment plant. The plant buys cartons of pre-calibrated pH meters, uses them for awhile and then tosses them in the dumpster. So, if you just happen to know someone in the waste treatment business, perhaps....

Tiffy's method of adding water, shaking it up and waiting is the way I was taught in a soil science class at an agricultural collage decades ago.

We allowed it to settle for days. The sediment may be useful in determining the usefulness of the measured pH value. (e.g. Sand will have little buffer capacity. Loam, humus and organic matter will have useful buffer capacity. Clay is another course in a different classroom.)

Elemental Scientific, located in Appleton, Wisconsin, sells small pH meters for around 35 dollars. This meter has a permeable glass tip, and must be kept immersed in a proper storage solution when not in use. Also, the meter must be calibrated using a standard test solution before it is used to take a reading. I have used one of their pH meters for several years, and it works fine. We grow blueberries in our yard, and repeated pH measurements are what convinced me to stop using tap water on these shrubs. Our tap water contains considerable dissolved limestone, and it will very quickly raise the pH of a blueberry shrub too high for successful growth.