subject: Improving Clay Soil Under A Lawn [print this page] Clay soils create problems in both gardens and lawns. By definition, clay soils are compacted. They stay soaked when wet, and turn rock hard when they dry out in the sun. When soils are intact, required air, water and nutrients cannot make a way through the soil. Thus, disease occurs. Roots are stunted. Beneficial micro-organisms couldnt survive. Plants are stressed and weakened, while specific weeds are actually encouraged in the process.
Improving clay in garden beds is normally finished by mixing organic matter as compost, peat moss, cocoa shells etc....Into the clay 4-12 inches deep or more. In this process, if done right, can instantly improve soil aeration and drainage, and can help create humus over time as beneficial soil microbes break down the organic matter. *
But, if you have a lawn clay situation, there is no way to till in organic matter down deep actually without tilling up the lawn. The standard advice is to top dress the lawn with compost, leave the clippings, fertilize organically and relax... for all of that organic matter at last to break down, convert to humus and help restructure the soil. The denser the clay, the longer it will take often years.
The problem with dense clays, unlike sandy soils, is that they mostly consist of microscopic mineral particles that are very tightly bonded, with little air space between them. The microbes that break down organic matter need air to survive. The only air you'll have when working with lawn clay is going to be at the surface. So, the surface soil will improve first, and very slowly the clay will change deeper - but only if the soil is bioactive.
A Thatch situation is a sure sign that your soil is not aerated and bio-active enough to break down organic matter.
A Faster Solution
Lawns growing in dense clays are often poor in color, thin and weedy. Adding organic matter or compost to the top of such a lawn may at last improve the lawn clay, however it takes a lot of patience. The total process can be speeded up by creating temporary pores and channels in the clay with Aerify PLUS Liquid Soil Aerator and Bioactivator. (Yes, we are promoting our product, but frankly, it is a real difference maker)
Aerify PLUS breaks down clay bonds to create microscopic airspace deep into the clay. Each application can work deeper. It also helps in generating and feeding beneficial soil microbes of all types (including mycorrhizae) at the same time. It helps in improving drainage in your lawn clay, encourages deeper rooting, mixes up nutrients and water in the root zone and helps in moving organic matter deeper into the soil.
Once your lawn clay starts to open up, the soil becomes healthier while earthworms start to appear in your soil in greater numbers. Earthworms will intensify and speed up the soil improvement process because they aerate the soil as the tunnel up and down. They also digest thatch and other organic matter in the soil to convert it into humus and rich, fertile castings.
If your lawn is growing in a weak clay soil, it will always be used to the problems that come with clay - compaction, poor drainage, fungus, moss, weeds, poor nutrient availability and color, root-stress and other undesirable conditions. Improve the clay which will improve the lawn. It is as simple as that.
