Thank you, Pam, for answering my question and giving additional
advice. After the first "grumpy" answer in this newsgroup I thought
"Oh, fudge! Shoot me! how helpful is THAT?".
I moved to South Carolina and am probably the most "organic" person in
miles here. The first year I sat in my 1acre yard and tried to pull
out weeds. At home I never ever used any herbicides, it just was not
necessary. Here we´ve wasted tons of water the first summer - until I
said it´s just too much just to keep some silly grass green. If you
don´t water enough, the grass dies, which makes room for weeds to grow
even more. We reseeded but it became cold earlier than usual. So the
grass did not grow thickly and dense enough. Again - room for weeds to
flourish in early-spring-like South Carolina winters.
I applied Lyme to adjust the pH of the soil (red clay - the plants
either dry out or rott in the moist ground or are taken by some
fungus, yumm). Nothing really worked out. Now with chasing a toddler
around I do not have the time anymore to do much in the yard (well, I
just cannot do anything and stay focused. 30-second-projects are about
what I get accomplished these days).
So what can I do with my lawn ( I treated only a part of it, so my
daughter still has places to play)? A nice neighbor told me that "Weed
& Feed" applied in winter made the lawn look better in spring. So I
blindly applied that stuff (I´ve never had heard of it, I am German
and still have to learn many terms and products of gardening).
Are there any internet pages to order organic fertilizers (do organic
herbicides even exist?).

Thank again, Pam!
Jana