understand your soil -- indicator plants

What is your experience with using indicator plants to check your soil quality?
There is quite a bit about them on the web:

Indicator Weeds and Soil Conditions at Garden-Helper.com

Weeds, PH, And Other Soil Indicators

 

Well, lets take a few from the list in the first website you link to:

We have literally miles and miles of light sandy soil along the coast round here. Never seen bindweed in it. Once you wander just half a mile or so away from the coast, we're all on heavy clay. Much bindweed.

Ok. I'll grant them that one.

On my land, I have a problem with creeping buttercup, including on the light sandy southeast facing bank side.

At my last house, this, along with bindweed, was about the only thing that would grow in my flower bed until I took drastic action and completely excavated the soil then improved it.

So I'm not entirely convinced by that site.

To my mind, there are only two relevant clues to soil condition. What does it look and feel like when you dig it, and how many earth worms do you see when digging it.

 

Hi Clueless,
seems like its a bit tricky when the indicator plants can grow in a very wide range of soils and conditions..

 

Well they're not really indicators if they are happy in a wide range of conditions

 

Thanks Loveweeds. Thats interesting.

It is certainly right about Dandylions - heavy clay and acid - have got loads round here in every garden.

 

well probably one has to know more about the particular indicator plant, not only the soil in which it grows but the climate etc. That bindweed might dislike the wind or wet at the coast coast -just a guess -though the soil is right for it.
As to the bindweed growing in clay soil -this meets the criteria of "hard crusty surface", clay can become quite hard when dried out. My mum had lots of bindweed in her heavy clay soil too.


Probably indicator plants should be used more as a hint rather than a reliable statement as the next passage from following source hows:

http://www.ces.ncsu.edu/cabarrus/staff/dgoforth/limefaq.html#L1A
There are indicator plants that grow better in acidic soils. When present, these plants indicate lime is needed. Broomstraw and chickweed are local examples. High organic matter will make some indicator plants less reliable. Even if the indicator plants are reliable, you still need to take a soil test to determine the rate of lime needed.
At one time farmers literally tasted the soil. They described soil as "sour" when the pH is too low, "bitter" when the pH is too high and "sweet" when the pH is suitable for good crop growth. If you wish to use this method, you will still have to rely on soil test until you have calibrated your taste buds.