How do I improve the clay soil in my lawn without digging up the lawn and replacing the soil? My lawn gets waterlogged and soggy in winter.

• Apply Gypsum at a rate of 2-3 handfuls per square metre in spring and again in autumn.
• Clay soils are dense and rich in organic matter, but it is locked up, gypsum works by breaking down the organic matter in clay soil.  
• It is a slow process that takes months, even years, it won’t happen overnight.
• You can purchase spikes to strap onto shoes to aerate the lawn by walking over it and help improve drainage, these are available from hardware stores and garden centres.
• Once you have aerated your lawn apply a light layer of Tui Lawn Preparation mix to the area to fill in the holes, this adds organic matter to the lawn and helps improve the soil structure. 
• This can be repeated each year in late winter/early spring when the soil still has moisture in it and the spikes can penetrate the clay soil easier.