The above photos were taken today of two dandelions growing in my backyard. I believe them to be a good example of “What do weeds tell us about the soil?”
If you have dandelions growing in your yard like my “Very Healthy Dandelion” then your soil conditions are closer to the gravelly nature of this soil: compacted sandy sediment, low in organic matter, and very low in calcium.
On the other hand if your dandelions are similar to my “Anemic Dandelion” then congratulations your soil conditions are progressing to the point where they favor growing grass. Your organic matter is improving and being acted upon by the indigenous soil biology. The pH of the soil is at our near 6.5. The availability of phosphorous should be low. Most importantly calcium levels should be high.
Patience, improving soil conditions and proper cultural practices will all have an effect in changing your dandelion crop from “Very Healthy” to “Anemic”.