weeds as soil indicators

Somewhere (can't find it right now) I read that the presence or absence of certain weeds can tell alot about the soil they are growing in. What are some of the indicator plants you know of?

It's true and farmers sometimes look out for weeds and how they are growing to see what's going on in there. It's by no means an exact science, while there are plants that will only grow in very acid, waterlogged soil with very little nuttrition in dappled shade, there are really only a few that demand such very specific conditions, if other factors are right then the plant can often tolerate conditions that wouldn't nomally be suitable for them.

A list from me isn't going to mean a lot to you unfortunately, I'm sure others will have lists though.

Yes, If have wild violets & moss growing together in my soil, I believe it needs some sweetening. I have been told that you can count on rich woodland soil here in Southcentral Alaska if devil's club (Echinopanax horridum) grows there. However, as Baa says, some of our local wild plants seem just as happy in the garden as the wild... even gravel. I guess that is why they are such successful 'weeds'.

Yep - violets & moss mean acidic soil (add lime)
Chickory means very lean soil
Buttercups - heavy, poorly drained soil
Plantains (that spelling looks wrong! Not the banana fruits) - compressed soil

what weeds to you have?
Tam

Well, I have lots & lots of plantain in my yard... so compressed I'm de-pressed! Of course, there are lots of dandelions, too. Chickweed is a real performer around here. The beds are full of plump, crispy chickweed... oh, joy!

Lets see - dandelions mean you have dirt or something like dirt ;-)

Tam

actually dandelions could mean you have cement. lol

In the veggie garden I have lots of lamb's quarters, chickweed. that creeping charlie stuff as well as (not sure what it is called bit its in the mint family), and lady's thumb? Little bitty pink flowers, grows like wandering jew. We also have the occasional nightshade and lots of red-root pigweed in some areas. Mostly I am cutting down lambs quarters. Fortunately its not totally unwelcome. We eat it when it is small.

Probably one of the hardest weeds to deal with here is 'horse tail' (Equisetum). The roots travel deep and far, snapping off as you try to pull them up. You have to dig and sift the soil to get rid of them.

My front yard is dandelions, plantains, creeping charlie and just a little grass. :-(
I've been hand pulling and using corn gluten for a few years now and the grass
seems to be gaining ground.

My biggest problem in the vegatable garden is grass (crab grass and all the other
sorts of grasslike weeds)! This year I seem to have tons of purslane though. That's
easy to pull but there's just soooo much. Not sure what purslane means w.r.t. soil
condition & fertility?

http://www.eap.mcgill.ca/Publications/EAP67.htm is a Canadian link but I noticed many of our popular weeds there.

http://web.extension.uiuc.edu/champaign/homeowners/980411.html has some weeds specific to lawns.

http://www14.inetba.com/littlefarmresearch/weeds.ivnu Looks like the areas where the Redroot Pigweed is abundant are high in N.