As an alternative to the way you're headed you might suggest that people who try to change the pH of their soil are starting an uphill battle with a lot of problems along the way. The solution is to leave the pH natural and plant plants which are adapted to the pH they already have. If you change the soil pH with additives, it is only temporary. Thereafter the pH will move around between chemical applications. Plants installed for a non-native pH will be stressed as the pH changes and will suffer pest and disease problems.

I'm not saying to change what you're already planning to do and say, I'm just offering a different direction for information. Now that I think about it, being an extension volunteer you might not be allowed to say anything the school doesn't approve.

Generally pH meters that are relatively inexpensive, less than a laboratory model is, will be unreliable and often those pH meters give different results from the same soil sample and also give the same reading with different substances. What does your Horticulture Agent say about this?

Hi dchall and kimmsr. Thank you for responding. dchall I understand your point and we do have a native plant booth at our fair. As volunteers for the extension center we must provide information to the public. If someone comes in asking what the soil pH requirement is for growing a plant we need to tell them and advice them on how to achieve that result. We do make a strong effort to advise organic methods. Kimmsr we are copying what was done at the Bartlett Arboretum in Stamford. The Soil Coordinator from the University of Connecticut advised them on the pH meter they bought and used for their fair. The did get the calibration to within .1 or .2 off perfect. I am going to ask the Soil Coordinator to work with us to make sure we have our meter calibrated correctly.

I hate to be a downer, as providing valuable information to the public is a noble goal, but I see the undertaking as being more problematic than helpful, unless there are a lot of details missing.

First is the quality of the testing. Provided you get a pH meter that is calibrated properly and gives accurate readings (and that is a big "if"), how will the participants know ahead of time to prepare a proper sample? pH ranges can vary rather significantly within a small area depending on where and how they were obtained. Those close to foundations, sidewalks or driveways will test higher than those taken from the surface under conifers and neither may be representative of the deeper soil out in the open.

And most plants, with a few notable exceptions, tolerate a relatively wide range of pH anyway, making adjustments (which, as dchall very clearly explained, are temporary at best) generally unnecessary in many cases.

And provided all the above is addressed reasonably and accurately and adjusting is found to be necessary, is there any follow-up testing to determine how badly they screwed up the process?

Personally, I think you are opening a can of worms.

Thanks for your input Gardengal. You all have raised valid concerns. I am going to meet with our Extension Coordinator and the UConn Soil Coordinator to discuss your points. Also it is a good idea if we do go forward with this to clearly outline soil collection instructions in any publicity for the soil testing.

There's a simple test for soil types that involves shaking up a sample of soil in a jar of water and watching the materials layer as they settle. I think kimmsr posted a link for the test, although I couldn't find it right now.

This could be a very good visual aid for people showing how the amounts of clay, sand, silt and organic matter vary in a given soil. You could set up a series of jars of different soils and maybe even relate it to the results on a paper soil test.

Maybe kimmsr can repost the link (the search function is not working for me right now).

Claire

As claire just posted, shaking the soil up in a clear container and making a study of the sediment is quite useful. The layer of sand relative to clay and organic materials gives one some idea of buffer capacity. This is the way we were taught in college laboratories decades ago.

The links may have been posted under a subject line about a Science Fair a month or so back. I will go Googling for science fair and gardenweb.com and if I find it I will report back here.

There are a number of these simple soil tests that people can use in addition to the nutrient and soil pH tests done by a soil lab and this list is one of them. Rather than using a pH meter that may not give accurate readings and would not tell people why their soil is at the pH is is at, perhaps a demonstration of these would be better adn would get people actually looking at the soil they have, hopffully.

1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Thanks Claire, Albert, and Kimmsr. I love your ideas of visualizing soil structure and being able to relate that to different types of soil they may have at their homes. Your ideas sound like a better way to educate the public than my extension office's original ideas. I am going to talk to the people in my office and see if we can change direction. Thank you all so much you have reminded me why GardenWeb is such a great resource.