Posted: 06/03/2017 at 13:47
Sorry, but potatoes do not break up soil and weeds. You do with all the digging needed to plant them and them keep them earthed up and then harvest them. Back breaking in poor or infested soils.
Rotavating is also a seriously bead idea for all the propagating reasons given above.
IThe best way to go is a spray with a glyphosate based weed kiler on fresh new growth. Follow the instructions on the bottle and add a drop of washing up liquid to help it stick to the leaves. It needs 6 hours of dry, preferably sunny weather to be absorbed and then takes 2 weeks to kill the plants right down to the roots. For strong weeds, a second dose may be necessary.
After that you can dig it over, pulling up every scrap of plant and root you find. Do not put them on a compost heap. Burn them or take them to the dump.
Then you can prepare the soil for whatever plans and plants you have. in mind. If you still can't work the clay after all the weeds are dead - it should be a bit drier by then as spring moves along - then cover it with copious amounts of composted material which you can somerimes buy in bulk from the council or eles take advantage of special offers of multi purpose compost or soil conditioners from local DIY and garden stores.
The worms will work it in for you through the year and you can and should re-apply every autumn once your plants have gone dormant.
Building raised beds is another possibility but will require some expertise and investment to build something sturdy and long lasting and attractive.