Clay soils create problems in both gardens and lawns. By definition, clay soils are compacted. They stay soggy when wet, and turn rock hard when they dry out in the summer. When soils are "tight", necessary air, water and nutrients can not move through the soil. Disease occurs. Roots are stunted. Beneficial micro-organisms can't survive. Plants are stressed and weakened, while specific weeds are actually encouraged.
Improving
clay in garden beds is normally accomplished by tilling or mixing
organic matter –such as compost, peat moss, cocoa shells etc...into
the clay 4-12 inches deep or more. This process, if done right, can
immediately 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 without tilling
up the lawn. The standard advice is to top dress the lawn with
compost, leave the clippings, fertilize organically and wait... and
wait... for all of that organic matter to eventually 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 or loamy soils, is that they mostly consist of microscopic mineral particles that are very tightly bonded, with little to no 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 little by little 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 color, thin and weedy. Adding organic matter or compost to the top of such a lawn may eventually improve the lawn clay, but it takes a lot of patience. The whole 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 apart clay bonds to create microscopic airspace deep into the clay. Each application can work deeper. It also helps generate and feed beneficial soil microbes of all types (including mycorrhizae) at the same time. It helps improve drainage in your lawn clay, encourages deeper rooting, frees up nutrients and water in the root zone and helps move organic matter deeper into the soil.
Once your lawn clay begins to open up, the soil becomes healthier and earthworms will start to appear in your soil in greater numbers. Earthworms will enhance 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 and convert it into humus and rich, fertile castings.
If your lawn is growing in a poor clay soil, it will always be prone to the problems that come with clay - compaction, poor drainage, fungus, moss, weeds, poor nutrient availability and color, root-stress and a host of other undesirable conditions. Improve the clay and you will improve the lawn. It is as simple as that.
FYI, I treated my own lawn organically for many years and top dressed with compost as well. Though the top 4-5 inches eventually got pretty good, the clay underneath remained gray and sticky. After a few seasons of treating with Aerify PLUS, it was as if all the organics that I had put in the soil finally became were able to be utilized down deep where I wanted it to go. My lawn clay soil became dark and crumbly more than 1½ feet deep- and earthworms abound.
*See Working With Wet Clay Soils in the Garden
Stuart Franklin is President of Nature’s Lawn & Garden, Inc. (http://www.natureslawn.com) a lawn fertilizing company and on line Web Store , located in the Buffalo, NY area. He is also the author of Building A Healthy Lawn: A Safe and Natural Approach (Storey Publications 1988), available through Amazon.com
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