If your clay soil is alternately cracked and waterlogged and looks like the clay we used to use in primary school then gardening is hard work. Getting plants to grow is difficult because the preponderance of clay in your soil excludes air and worms need air. Without worms you have no worm droppings to improve your soil fertility and no worm tunnels to improve its drainage.
There are clay soil drainage solutions. All revolve around adding organic humus to the soil.
Clay drainage solutions take time. Even if you cover the ground with a 12in thick layer of compost it needs to be mixed with the clay at the particulate level. This takes time.
First organise your source of compost. You need a lot of compost, so you need a large compost bin or bins to be more accurate. Forget those piddly little plastic containers that cost £60 or more. You can make your own free compost bins from old pallets.
Everything made from vegetable matter can go into your compost. That includes plain cardboard from packaging, toilet roll centres and boxes. All your grass cuttings and weeds can be composted. You can include wood ash if you burn your own logs and eggshells, too.
Give family and friends empty buckets with lids to collect their own potato peelings and tea bags in. Collect hedge cuttings from fellow gardeners who don’t want them. Take neighbours grass cuttings, it will all provide you with more compost.
Invest in a garden shredder or chipping machine. You can buy one for less than £100 and these will help you to turn shrub and tree branches into woodchips or compost.
In the autumn leaves are a nuisance to everyone. Let neighbours know that they can drop off their bags of leaves with you. It’s all grist to your back garden compost mill.
You need to turn your compost every few weeks to give the decomposition bacteria the oxygen they need to do their job quickly. You will get compost without any turning over your compost heap, but it could take a year or more instead of a few months. The choice is yours to make.
When your compost looks and feels like the stuff you buy in bags it is ready to use.
You can apply it evenly over your garden or concentrate on particular areas. I recommend concentrating on the wettest parts of your garden first. Cover them with a 3in thick layer of compost and mix it in as best you can. Ideally it should be dug in with a garden fork, but it will mix in on its own over time as worms start burrowing through it. Place the next batch of compost in the same location. With 6in of compost now applied it is just a matter of time before worms have done all the particle-level mixing that is required. Even with 6 inches of compost it will take three years before you notice any change in your soil.
Once you have applied 6 inches of compost to your worst area, move on to another area with your next compost application.
You can never have too much garden compost. I make and use 3 tons of it every year in my own free compost bins. I have 10 bins and I need every spadeful of compost because my soil is worse than clay it is sandy. All nutrients wash straight out of it and I need to work in all the compost I can get.