Using lime to improve clay soil?

Yesterday I got a haircut and I was complaining to my barber about my clay soil. He mentioned that he had heard that lime can be used to improve/break up clay soil. Is it true? Has anybody actually used lime to improve their clay soil? If yes, details please. Thanks for your help.

YardenMan,

Gypsum can be very beneficial to clay soil, as is explained on this web page:

http://www.awgypsum.com/benefits.htm

MM

Lime can help to improve the soil a little by enabling clay particles to form larger crumbs in the tilth. Lime can help to prevent certain diseases such as Brassica Clubroot too. If you are thinking of adding lime I would suggest having your soil tested for nutrients and pH first and looking at the structure of your soil, it may not be as bad as you might think. I'd also like to say it's no quick fix, you're looking at 3 years at least before it starts to show improvement and you will need to add lime most years to keep it going too and you may be restricted in what you can plant.

Best thing you can do to improve the structure of clay soil is amend, amend and amend again with good, well rotten manure and other composts, don't dig it very often, it destroys the structure. Clay is always going to be clay, the only way to get rid of it is to dig the lot out and replace with other kinds of topsoil.

We have clay soil, we also have a high water table but we've learned to love it, I'd much rather have clay than sand, the plants prefer it too.

I'm sorry MainieMan but I disagree that Gypsum is beneficial for clay garden soil. We looked at using it for our garden but were advised against it. Here's more information from Linda Chalker-Scott, Ph.D., Extension Horticulturist and Associate Professor, Puyallup Research and Extension Center, Washington State University.

The Myth of Gypsum Magic

Adding gypsum to your yard or garden will improve soil tilth and plant health

The Myth

Upon continued prodding from one of my university extension colleagues, I recently watched several episodes of a well-known gardening program on television. My kids joined me, alerted by my animated responses to the hosts non-stop torrent of advice. Among many amazing discoveries I learned that by adding gypsum to my yard or garden I would improve my problem soils by changing the particle size and loosening compaction. Further searching on the web revealed that gypsum would also improve drainage, decrease acidity, and eliminate soil salts. Previously, I had heard of gypsum for use in soil reclamation projects, but not for a typical urban landscape. Since gypsum is simply calcium sulfate, could this chemical truly transform soil structure and serve as a fertilizer for yards and gardens?

The Reality

This myth falls into the category of agricultural practices misapplied to ornamental landscapes.

Gypsum effectively changes the structure and fertility of heavy clay soils, especially those that are heavily weathered or subject to intensive crop production. Gypsum also improves sodic (saline) soils by removing sodium from the soil and replacing it with calcium. Therefore, one can see improvement in clay soil structure and fertility, and desalinization of sodium-rich soils, by using gypsum.

What other effects will gypsum have on soil and plant health? There are a number of scientific studies on gypsum usage both in the literature and on websites. Briefly, researchers have found:

Gypsum does not usually change soil acidity, though occasional reports of both increasing and decreasing pH exist;

Gypsum can increase leaching of aluminum, which can detoxify soils but also contaminates nearby watersheds;

Gypsum can increase leaching of iron and manganese, leading to deficiencies of these nutrients;

Gypsum applied to acid soils can induce magnesium deficiency in plants on site;

Gypsum applied to sandy soils can depress phosphorus, copper and zinc transport;

Gypsum can have negative effects on mycorrhizal inoculation of roots, which may account for several reports of negative effects of gypsum on tree seedling establishment and survival;

Gypsum is variable in its effects on mature trees;

Gypsum will not improve fertility of acid or sandy soils;

Gypsum will not improve water holding capacity of sandy soils; and

Gypsums effects are short-lived (often a matter of months)

With the exception of arid and coastal regions (where soil salts are high) and the southeastern United States (where heavy clay soils are common), gypsum amendment is just not necessary in non-agricultural areas. Urban soils are generally amalgamations of subsoils, native and non-native topsoils, and in home landscapes high levels of organic and non-organic chemical additives. They are also heavily compacted and layered (and gypsum does not work well on layered soils). In such landscapes, it is pointless to add yet more chemicals in the form of gypsum unless you need to increase soil calcium levels. This nutrient deficiency can be quickly identified by any soil testing laboratory for less than a bag of gypsum costs. (If
you need to improve sulfur nutrition, its wiser to use ammonium sulfate). To reduce compaction and improve aeration in nearly any landscape, application of an organic mulch is more economically and environmentally sustainable.

The Bottom Line

Gypsum can improve heavy clay soil structure and remove sodium from saline soils

Gypsum has no effect on soil fertility, structure, or pH of any other soil type

Most urban soils are not improved by additional gypsum

Before adding gypsum or any chemical to a landscape, have soil analysis performed to identify
mineral deficiencies, toxicities, and soil character

Adding gypsum to sandy or non-sodic soils is a waste of money, natural resources, and can have
negative impacts on plant, soil, and ecosystem health