Clay

In a word no. All of them require a fair amount of effort. You need to dig in plenty of organic matter, sharp sand and 5 mm. grit. Plus, do a test and add lime according to the info on the testing kit.

It's best to dig it over in late autumn and let the frost break up the clods for you to make it easier to dig in all the things advised by owdboggy. Another tip - whenever you plant anything, back-fill the hole with compost, not the clay-ey soil.