Tilling those "weeds" in allowed them to become part of the organic matter your soil probably needs, although tilling also brought up more "weed" seeds that could germinate and grow requiring tilling again, or covering with a good mulch.
More than likely what your soil really needs is lots of organic matter more than something called claybuster fertilizer.

Claybuster - Aged compost with addition of horticultural pumice. More expensive than some bagged composts but a useful product.

The directions for use that I see about a couple of different, it appears, products called claybuster is to add a small amount to your clay soil in that planting hole which most likely will make it much easier for moisture to flow into that planting hole but since the soil outside of that planting hole has not been changed the water will not be able to flow out and will then result in your having a planting hole filled with water with no place to go which will drown your plants. Probably not a good thing to do.
Clay soils need a lot of organic matter spread over a very large area to prevent that type of occurance.

It looks like, then, I shouldn't use a tiller to get rid of weeds. I'll just do it manually.

vgrandja, feel free to start your own discussion, and include pics of your weeds if possible. As hortster said 2 years ago, the preferred method for eradicating a weed depends on the particular weed.

The "preferred" method of "weed" control depends on a number of factors, but not hte particular "weed". For some the "preferred" method is to spray poisons all over the place while for others the "weeds" must be pulled and thrown away because those people do not understand those "weeds" used valuable nutrients from the soil they grew in and tossing them wastes those nutrients.
For some of us simply covering the "weeds" is the best method even though we know some (Quack Grass for one) will simply grow through and need to be pulled out later.

Kim, if you didn't make assumptions and attack people on something they were NOT going to say, it would be a lot better, if you would actually read these dicussions instead of spending all of your time up on your preachy soapbox spouting sound bytes.

I don't appreciate your assumption about what I left unsaid and am sick of seeing you do it to other people, too. You spend a lot of time and effort attacking blindly, taking things out of context, weirdly arguing with people who share your viewpoint. It's maddening! Everyone besides you is NOT always wrong in some "implied" way.

When some new member asks a brand-new question on a years-old discussion, they don't usually respond to answers to their questions, so I find it useless to go into much detail in those cases. If you would like to add details in those instances, feel free to, but please stop attacking people for things they didn't even say.

purpleinopp, sorry you misread what I said and took offense at it. I did not attack you, or even imply that you were wrong. I simply offered another view point, which is the purpose of these forums.

If you have annuals, mulching & or tilling will stop everything. A good blanket of mulch 2-4 inches deep will stop seeds.
If you have perennial grasses, wild garlic/onions,wild blackberry/dewberry.
Then tilling will help them grow & spread.
Forget the hoe or rake, a shovel & sweat will slow these weeds down.
Round-up if you are not an organic gardener, will help.
But I know a field that still has these weeds & it was sprayed with round-up 2 year in a row & burned the third year. The gardener moved his garden after that.

Does clay buster contain weeds? I spread 2 bags along with gypsum in my garden and tilled it in, seeded the garden and saw a burgundy hue throughout as it was sprouting, it turned out to be portulaca growing evenly all over the garden.

I would say the gypsum & pumice are working over time.

Portulaca flowers tolerate many kinds of soil but prefer sandy, well-drained soil and love the full sunlight. These plants are excellent for their high heat and drought tolerance and will seed and spread themselves very well