It is difficult to grow a good healthy turf in poor soil and the presence of many "weeds" can indicate a soil related problem since they most often prefer soil conditions that prevent a good, healthy turf from growng. Spraying any kind of poison to kill any "weed" is simply treating the symptoms of a problem and not the cause which needs to be corrected.
Start with a good, reliable soil test so you will know what your soils pH is and which of the major nutrients may need some adjusting. At the same time you can do these simple soil tests,
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2. Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
which can help guide you in making that good, healthy soil your grass needs to grow strong and healthy.

Here is a link that might be useful: University Of Tennessee Cooperative Extension Service

I'll definitely test the soil to see where exactly the deficencies lie. Thanks for the tips.

But I'm also interested in getting a sense, from people who have battled weedy lawns like this, of whether the battle is winnable. Even once I've fixed the soil deficencies, the weeds won't just go away. And in the meantime they'll continue to spread. (I forgot to mention before that I also have large, rapidly expanding colonies of clover).

So my larger question is whether it makes sense to put in the time and energy into pulling out the vast array of weeds and slowly bringing the soil back to where it should be, or is it more practical to just bring in new soil and plant new seed? I would rather avoid that expense, but I'm also wary of putting countless hours into something that will continue to be a losing battle.

A good healthy turf needs about 1/2 inch of thatch and if your soil is good and healthy the Soil Food Web will keep that thatch in check and will not require someone using a machine to dethatch the lawn. The soil tests may indicate your soil only needs a little work and not a overall rebuilding or they may tell you to totally rebuild.

I agree. If you are getting ready to do a redo, spend a few more bucks on a soil test.

Clover is the least of your worries. It happens that clover is an indicator of poor fertility in the soil, so that confirms what you suspected. The real problem is creeping charlie. After reading about creeping charlie here for years, the only solution (organic or otherwise) is physical removal of the top few inches of soil. Some people have reported using RoundUp against it but they were less than satisfied. Theoretically Brush-B-Gone should take care of it but I don't read about it much. If you want to stick to an organic approach, those chemicals are strictly out of the question. Apparently creeping charlie's roots are very shallow so soil removal is not that big a deal. Hire a landscaper with the right blades and a front end loader and they can do that in a day.

I am extremely hesitant to discuss a possible Round Up solution on this organic forum, but this is at least a bare minimal use of the product. If you can stuff some of the creeping charlie into a small jar of diluted Round Up (2/3 water), and let that sit for several days, the RU should be taken to the roots and kill that part of the plant. This method has been used against field bindweed with some success. The beauty of this approach is twofold: you are not spraying the entire yard with chemicals and the plant is so interconnected that if you can kill the roots in one spot, a lot more of the plant will die.

I'm interested in what kimmsr thinks about that kind of non-organic approach.

I appreciate all your thoughts, especially knowing that this forum is not the ideal place to be discussing potentially non-organic solutions to these problems. It does make sense that if I do end up going for a redo, digging up what's there should be an easy step to add.

In any case, I'll start with the soil test and experiment a bit with these ideas. For now I'll also keep digging them up by hand, a few at a time. I haven't given up on the war of attrition.

A crazy question...

Why worry about the creeping charlie weed/grass? It's soft and it's short and green and looks like grass... Easy on the feet... Healthy and spreads like crazy.... It doesn't have stickies that glob all over your shoes or tall shoots....

There are many things that I can think of that are far worse -- Bare dirt, rocks, stickers, thistles, dandelions, little Oak trees (AKA "Organic" Punji-stick traps)...

I also agree on the Clover -- Not much of a weed there... and a fine indicator that your soil is really poor stuff. 35 years ago, most all grass seed had about 25% clover in it on purpose... It fixes nitrogen out of the air -- so you can cut your fertilizer requirement quite a bit... I am actually planting out some Clover in my back yard for exactly this reason...

Thanks

John

It's a fair question.

In general I don't mind a little charlie, but there are sections where it looks to be plotting to completely push out the grass, and that I'd like to avoid.

The other problem goes back to the zoysia. When it's dormant, which it is for almost half the year (including almost the entire spring), the charlie is bright green and the grass is straw brown. It's not a pretty sight.

I'm not aiming for perfection, I'm just looking for a lawn that won't be an ongoing battle.

Hi, I think you need to get rid of the weeds first. I used Weed B Gon and had very good results. Took care of the clovers and dandelions and other stuff. Some remarks on WBG...

-Bottle says it covers 16000sqft but that is only for warm season grasses. It only covers half for cool season grass.

-Even though it says it works in 24hours, I did not see it work that fast. Well, the clovers looked depressing, that was all. It took about 2 weeks to notice the results.

-You will see weeds growing like they're on steriods in the first few days after application. This is normal as it is depleting the weed's nutrients.

I did some searching and you need specific type of WeedBGon to kill creeping charlie. One user on GardenWeb commented...

"We tried many kinds of weed killers, and the Creeping Charlie in our lawn laughed at every kind UNTIL... it was pointed out to us at a garden and hardware store that we needed the Weed B Gone with the label that prominently says it kills Oxalis weeds. It is a different kind from Weed B Gone Max. We had a hard time finding the Oxalis specific formula Weed B Gone, but after several stores we got some, and my friends, it was the magic we had looked for. Charlie was gone after a couple of applications. We had tried everything from manually weeding, to plowing under whole patches of our yard, and a lot of expensive useless chemicals in between. But I'm here to say we have the problem conquered with Weed B Gone Oxalis formula."

Looks like you need Weed B Gone that kills Oxalis weeds.

Things like "Weed B Gone" and "Roundup" are unacceptable to anyone that is an organic gardener. Both are very harmful to our environment and there seems to be some evidence that they are creating problems in our genetic makeup, even in people not exposed by spraying them.
Creeping Charlie is spread by roots as well as by seeds so removing several inches of soil is not a guarantee that yo will not have it in your yard in the future. Spraying poison today is not guarantee that there will be no "weeds" in the yard tomorrow.
The best way to keep your turf grass looking its bes is to provide a good, healthy soil for that turf grass to grow in and manage it so it will grow in good and thick and not allow "weeds" to gain a foothold.
Spraying poisons is harmful to our environment and is only a wshort term treatment to a problem. Spraying poisons is not a long term solution to a "weed" problem.

Yes, I forgot to add that this is not entirely organic. =] I think the only organic option would be to start over in the fall.

I appreciate the several different voices and perspectives here.

One thing I'm still not entirely clear on, though, is what the organic purists recommend for this situation. I totally get that having healthy soil is the best defense against weeds gaining a foothold, and improving the soil is my long-term plan.

Just to be clear, though, what do you recommend when invasive weeds already have a tremendous foothold? If topsoil removal doesn't work well, pulling them up by hand (as I've been doing) seems even less likely to work. So would true organic gardeners just leave them as is and move forward with soil improvements?

I'm not totally opposed to that. I'm not looking to have the nicest lawn on the blockÂI'm just looking for something relatively low maintenance and not entirely offensive to the eye. All of this would be much easier if not for the zoysia.

Can you post a picture? Seeing what you are up against might swing things around.

In the last week the zoysia has turned green, so the weeds don't stand out quite as much, but hopefully you can make out what it looks like. "Lawn 1" covers about 1/4 of the entire lawn, but reflects what most of it looks like. "Lawn 2" is a detail of "Lawn 1."

Here is a link that might be useful: lawn photos

Thanks for the pix. The yard is not as bad as I was thinking. Creeping Charlie is still a serious consideration, though. There is no organic solution to clearing only the broad leaf weeds out of a lawn.

Could it be that in the close area in Lawn 2 that there is too much shade there for the zoysia?

There are sections that are worse and others that are better, but no, it's not terrible. Not great, either. But when I look out and see all that Charlie I see a problem that's only going to get worse. So I keep wondering, if you're starting off already in the hole, is it better to give yourself a somewhat clean slate or work with what you have?

Down the middle of the photos is about where the zoysia ends. To the right it's all zoysia and full sun.

I've gathered together the material for the soil test. Now just have to get over a cold and go out and do it.