Hello! My lawn is laid over lots of building rubble and hardcore. In some areas the depth of soil is only an inch, and in others a gardening fork will go all the way in, so around 30cm. Because of this, the drainage is very poor, and the lawn is quite 'hilly' - I.e. It isn't level. I want to remove the rubble from underneath, improve drainage and make the surface completely level before laying new turf. Please can you give me some tips on the best way to go about doing this? Many thanks!! Alan Brady
Certified GKH Gardening Expert
There is no easy way Alan, it's a lot of hard work, but your efforts will pay off and you can have a nice lawn when you are finished.
Are you on your own on this? Or can you hire a crew? Or talk a mate into helping you out.
Start by removing the existing turf by shallow digging with a maddock, shovel and rake, by sort of peeling it back and rolling it up, or picking up the pieces. If you have space, you can pile and compost this material for later use. If not you will have to dispose of it.
Once the subsoil is exposed, you can go over it with digging fork, pick and shovel and loosen the rubble where it exits. Rake out the rocks and debris, loosen the hard pack.
Once you have the undesirable material raked out and disposed of, you will need to estimate the amount of fill soil and order enough to fill in the low areas. The other way is to pick and loosen the higher spots and move some of that soil into the lower areas to level the grade.
Are you tired yet? Take a break and then order some compost to mix with the top soil. I don't know how many square meters you have, but buy enough bulk or sack compost to cover it at least one inch (2.5 cm) deep. Dig this compost into the soil surface and rake it all out level as you can. Water it to settle the soil. Rake again to a fine grade that you will lay your new turf on. Or the option is to seed it. But seeding better wait until spring now. Sod may still take before hard winter sets in, although safest is to wait for spring growing season for either. Then it will be able to get a good start.
There is not much you can do about drainage, without a lot more work and material. If you really think the drainage is a serious detrimental issue, then you may need professional help to design a drainage system with tiles or replacing the native soil to a suitable depth.
The leveling will help to eliminate standing water in low spots. And manage an irrigation program that is appropriate for the soil type and not too heavy, so that it doesn't stay muddy wet and rot the roots.
Hope that helps, Don