Unfortunately weed seeds are in most composts/soils you can buy unless it is sterilized. Corn gluten meal does have preemergent activity, but it is nowhere as good as chemical preemergents. If you mow regularly so that the annuals do not go to seed then they will die this fall and you should have much less of them next year. The perennials however will probably return and you will probably have to continue to pluck them unless you can find an all natural selective herbicide.

As an aside, lime is generally used to raise pH and provide calcium and/or magnesium to the soil, and will probably do nothing in regards to the thinness of the lawn under the trees.

Suggest calling a lawn service and plead your case with them. I have my lawn taken care of (fertilizers that is) by one and it costs me what Scotts was to purchase myself. Lots of them are trying to be very "green" these days. Unfortunately chemicals do kill and control weeds the best, just the way it is.

Thanks, folks.

I really just cannot use anything toxic to the chickens. There's no way to keep them off the lawn for more than a day or two, and we do eat the eggs... so I'm just not willing to use chemical pesticides/herbicides at all :(

I guess I will go around and hand-dig all the weeds I can. Then continue with the corn gluten. Shall I apply some more now?Usually I just do spring and fall, but is there any harm in doing it again now?

I do think maybe part of the issue is that there are wide swaths of lawn where the soil is quite poor... it's mainly the very hard clay-soil that the excavators pushed around the yard, and less "new" loam. In those areas the grass is struggling. Perhaps if I got more good soil and reseeded those areas this fall, the weeds would have harder time getting a foothold? I can temporarily fence those sections off from the chickens for a couple of months. And then do the same again in the spring if there are more areas that look like they need help.

What do you think of that plan?

If you want to kill weeds, you really only have 2 options: using and herbicide or doing it manually. Manually is a pain in the rear. That is why scientists spent decades coming up with an easier way to do it. i.e. herbicides

They do make some contraptions that make weeding easier. The weed-hound is one I like.

I'm certanly no expert but I'd say no matter what you do your going to get weeds eventually. Even "chemical free" services cannot keep 100% of the weeds away. Do you have a nursery/garden center near you? swing by and ask them what they sell/suggest.

How about getting a tank sprayer and using it to spot-spray vinegar on the weeds? Beats the heck out of digging them out one by one and should be pretty easy to apply if the weeds you're attacking are broad leaf weeds.

totally^ I was just reading about 'horticultural vinegar' which is 20% rather then 5% acidity that household is. I wouldnt let hens on it tho i think.

Hmmm, I will look into horticultural vinegar. Regular vinegar is fine for hens (people put apple cider vinegar in their drinking water as a tonic, but it's way diluted of course...).

I have so far spent about 6 hours hand-digging and it's grueling. I'm maybe 1/4 of the way done :(

Since vinegar is basically Acetic acid, call around and see if you can buy some. It is can be purchased as 100% material and can be diluted down to the desired concentration. Don't by the laboratory grade as it cost an arm and a leg.

http://en.wikipedia.org/wiki/Acetic_acid

"I have so far spent about 6 hours hand-digging and it's grueling. I'm maybe 1/4 of the way done "

So, if you weeded 1 hour per day, you would be done within 3 weeks? If you don't want to use chemicals, that is the obvious answer. Don't kill yourself with marathon weeding sessions. If you just keep at it, you will reach your goal.

Yeah, but the plantain is all going to seed now. And I can see what happens if that's allowed... there are some vast mats of plantain babies in places where that happened earlier. I want to get them before that happens this week!

Believe me, I don't want to do marathon lawn weeding either. I have a 1000 sf veg garden and lots of perennial beds I already have to stay on top of :(

Have you thought about maybe putting up temporary fencing and treating half the lawn with a product such as Weed-b-Gone? You could keep yourself and the hens on the other side while the weed killer works. After a couple months I am guessing all the chemicals would be used up and should be safe. Then repeat on other side

Wouldn't it be simpler to contain the hens in a temporary fenced area while you're treating sections of the weeds?

Pay a neighborhood kid?

Just a suggestion. Maybe try some vinegar added to boiling water in a large kettle and selectively pour over each weed. Cutting off the top growth of the larger weeds should help make it more effective by getting to the root zone quicker. See if you can enlist the help of a friend to ease some of the burden of the task.