Wherever you are in the United States (a location is a distinct help) you most likely will not be planting for several weeks so the easiest method of eliminating those "weeds" would be to cover the area with newspaper and the newspaper with a decorative mulch to hold it in place and hide it and let it sit awhile.
That soil, hard and compacted, needs organic matter, compost, shredded leaves, any vegetative waste.

The soil is hard because it is dry. To soften the soil, water it. Several on-of cycles may be required.

If rhlee is in California wetting that soil may be a big problem. The state water there is ready to impose fines of $500.00 per day for people that waste water although several cities are just as ready to impose fines of $500.00 per day if property owners do not keep their grass green.
Covering that soil with a mulch is the simplest method of getting it ready for planting, in the future.

This post was edited by kimmsr on Fri, Aug 1, 14 at 6:36

No-till lazy weed control: Layers!

And leaving roots in the ground as organic matter.

Cut the weeds off, close to the ground, leave the cuttings on the bed, add an inch or two of grass clippings or a thicker layer of dry leaves, water the area, and cover it with cardboard or several layers of newspaper.

Top that with 4-6 inches of mulch (tree shreddings, dead leaves, grass clippings, whatever you can scrounge) and leave it until you are ready to plant next spring. It should be much improved.

If you have clay soil, the only way to overcome the mud => brick => mud cycle is to increase the organic material. The lazy way to do that is to layer the organic stuff on top and let the worms drag it down.

Also, if you have the right climate, plant some DEEP-ROOTED annuals vegetables like okra ... in the fall, cut the stalks off at ground level and leave the roots to decay in the ground.

I agree, and so does this microbiologist

Here is a link that might be useful: Brief tutorial about 'dirt'

Yep, should have mentioned, I'm from London, UK.

Thanks for the replies, will definitely try the newspaper mulching.

I didn't know I could keep the cut weeds and use them for mulching, great tip.

Interesting video btw.

What we call "weeds" are really plants we do not want growing where we do not want them and they use nutrients from the soil. Pulling them out and throwing them in the trash is simply a waste of those nutrients while putting them back where they came from, the soil they grew in, will put those nutrients back for use by the plants we do want.
Some of those unwanted plants can be very aggressive and others may root from stems and those a gardener may want to be very careful of putting back into the soil.
If someone has clay soil and it is hard and compacted and difficult to dig in that soil is telling you it needs organic matter ("weeds" are organic matter) to make it workable.

rhlee - now I know where you are situated I'll chip in. I also have clay soil and there is an optimum time to dig it. That is in spring or autumn when it is damp but not too sticky and not yet dried out. At the moment I would at least wait until after it's rained before trying to dig.

I would do it like this. Get a proper garden fork, not a little hand fork. Forget tillers unless you are doing a large open area like a veg patch. And forget prongy cultivators as they don't dig deep enough. It is a waste of effort to dig and then to weed separately. Do it all in one action. Slowly work through the beds digging a full fork depth (not 2 inches) and removing weeds as you go. Go carefully around established plants. Put as much organic material as you can onto the beds - make compost, get rotted manure, put down autumn leaves, whatever. You can turn any annual weeds under as you go or you can put them on the compost heap if you prefer. Perennials like bindweed and couch grass must be removed thoroughly and dried totally before putting on the compost heap.

I really don't recommend the newspaper method under our conditions. I have tried it, and the cardboard method, and all I get is compacted soil under the paper, weeds coming through it and a barrier to properly cultivating the soil. Also, and I know this sounds odd, I don't think the layering technique is really in keeping with the style of gardening over here where we tend to like to see some nice turned earth in a well defined , crisp edged bed, not a surface covered in various organic materials. But that's just a matter of taste. Don't worry about hurting the worms. They'll burrow down if they're disturbed. If you do happen to spear a few it is of no consequence in the sum of things.

It has been pretty warm and relatively dry in London recently so it might be better to overhaul the beds later in the year. In the meantime just cut back weeds to prevent seeding. If anyone near you has a tree surgeon in with a chipper they might be prepared to let you have some wood chips if you can provide bags. They make a good mulch.

Later on, when you are just doing maintenance and want to get a few weeds out, a hand fork is far better than a trowel which is mainly designed for planting.

Clay soils get compacted because the soil particles are small and fit tightly together. Once adequate amounts of organic matter are worked into clay soils they will become workable. It can take a lot of organic matter and time before that happens however, although the top few inches can be made workable quickly. That, unfortunately, does not solve the drainage issue, which requires time for the Soil Food Web to work that Organic matter deeper into the soil.

Kimmsr - I mentioned adding as much organic material as possible above. Another thing is that the OP is in London so the soil has probably been a garden for at least a century or more, has been abused by the dumping of ashes and other city pollutants and has been worn out over that period. So again, organic matter is important. But that is not the whole story with clay. There are still good moments to cultivate and bad ones depending on the soil moisture. Clay soils in the UK can be potentially extremely good nutrient wise - just difficult mechanically. My allotment is heavy clay for the most part. I have added compost and manure for over twenty years but it still needs careful handling.

One other point - I didn't see any reference to a drainage issue. It's very unlikely to be a problem.

Clay soils everywhere are fairly fertile except in addition to not allowing a plants roots to move around the clay particles lock up those nutrients so they are not available to the plants.
All clay soils not well amended with organic matter have drainage issues, because the tightness of the particles does not allow water to flow through very easily.
Quite often I have found that someone with clay soil has added a small amount of organic matter every year and still does not have a good, workable, soil because there is not enough OM in the soil.
A friend that gardened with the clay soils of England and then Tennessee tells me they both need ample quantities of organic matter. There is nothing wrong with either one except probably the lack of adequate OM. I have worked with both clay and sand soils (as well as loam) in many places and have found that all will benefit from the addition of organic matter, but it needs to be an adequate amount, enough to bring the level in the soil to about 6 to 8 percent.

We can certainly agree that 'all will benefit from the addition of organic matter.' I will continue to disagree on the drainage issue, unless of course we are not thinking of the same thing when we refer to drainage. If your definition is 'does not allow water to flow through very easily' that is not a condition I have ever experienced in all the years I have gardened on clay soil. Plus the OP made no mention of a drainage issue.

I didn't know I could keep the cut weeds and use them for mulching, great tip.

==>> lets be clear... you would do that BEFORE THE PLANT GOES TO SEED ... else wise you will just be spreading weed seed ...

green manure.. is green manure... its part of the compost theory ..... but seed pods should be throw away ...

bunch of key words for searching and learning ...

klen

I have heavy clay too and it's miserable to work with, although things DO grow in it...I've been adding organic matter over the years to improve it but it's still a work in progress. I have taken to digging a big hole and filling with bagged soil and planting in that...Be careful about tilling if you have weeds that will come back from small sections of root...that would be a nightmare - goutweed, anyone?

It never ceases to amaze me the number of people that don't seem to think of "weeds" as plants that remove nutrients from the soil they grow in.
More often then not I find people adding organic matter to the soil, but not in large enough quantities to do much. An inch or two of compost each year may not be enough organic matter to do much of anything. The same with mulching, an inch or two of a mulch is not enough to do what mulches are supposed to do.
Add enough organic matter, that is compost plus other vegetative waste, to get the amount of humus (the residual level of OM in soil) to 6 to 8 percent.