what to add to clay soil to improve/break up?

Answer 1

Lots and lots of organic materials. Compost, sawdust, lawn clippings, leaves. Mix them in to a depth of 12" or so. If you don't have access to a rototiller you can do it with a spade or a garden fork.

Some sand might help if it's not already sandy.

Try not to work the soil when it's overly wet. Wet clay soil gets compacted and this makes it worse.

Answer 2

Clay Soil Conditioner

Answer 3

Gypsum is great for breaking up clay soils. You can also add organic matter in the form of peat moss, compost, manure, or anything else you can get your hands on. Your city or county may have a leaf recycling program that you can get stuff from relatively inexpensively. Put down a good layer and till it in.

This is a long term project. If you are using it for a garden, do this yearly and in a couple of years you will have garden soil that the plants will love.

If this is for a lawn, you can continue to improve the soil each year by using a plug aerator each spring and raking in compost or peat moss and continuing to apply the gypsum.

Gypsum is not the same thing as lime.

Check out our website for more gardening ideas at-
http://www.gardening-at-the-crossroads.com/

Good Luck and Happy Gardening from Cathy and Neal!

Answer 4

Peat Moss mixed into the soil and start a compost pile so you will have something to add in the future. Coffee grounds are good to add at any time.

Answer 5

Garden lime (Gypsum). Sprinkle over the soil according to directions on the packet and wait - probable 2 or three months will begin to show improvement.

Answer 6

Gypsum and lime are diffenent products with different purposes. Lime will raise ph, gypsum is a soil conditioner so soften a hard soil.

Answer 7

There's a product called Clay Buster that's pretty good. Also, a good compost will help.

Answer 8

The essence of amending clay soil is to permanently loosen the soil's structure, using coarse sand and coarse organic matter, to allow free movement of air, water & roots through the soil. Avoid trying to change a small area. Plants will have a difficult time making the transition to the surrounding clay soil, effectively limiting their growth to the amended area.

A typical cultivated soil will have 50 to 60% mineral particles made up of sand, silt & clay, 1-5% organic matter, and 40% pore spaces between the particles, which will have varying amounts of air and water in them. It is the organics and spaces that create the structure of a good soil. If the goal were only to shift soil texture from clay to clay loam just adding sand would be enough. Soils with more than 40 % clay are called clay soil while if they have only 30% they are in the loam range. This soils texture would require 10% volume replaced but that doesn’t address the structure this creates.

If just sand and clay soils are mixed together, the large pore spaces of the sand just fill with the smaller clay particles. This results in less total pore space than either the sandy or the clay soil alone. A simple analogy is making concrete, which entails mixing sand with cement - a fine particle substance. After mixing with water the particles lock together with nothing to separate them. Neither soil nor concrete becomes crumbly until it contains nearly 50% sand by total volume. For most sites, it would be prohibitively expensive to remove half the existing soil and add an equal volume of sand and then till it to the necessary 18-24" depth. It is not reasonable to try to change the texture of an extreme soil. But it is possible to change its structure. So the goal is to alter a bit of both the texture and structure (tilth).
Organic matter builds soil tilth in a couple of ways. First, the organic matter coats soil particles, physically separating clay particles. Second, and more important, microorganisms that degrade organic matter produce byproducts called humic acids that bind individual coated clay particles together into aggregates. Particle aggregation in the topsoil reduces crusting, increases the rate of water infiltration, and reduces erosion and runoff. It is effectively impossible to add to much compost for as it decomposes it both decreases in volume and produces more humics.
The two most effective amendments for clay soil are coarse sand and coarse composted organic matter. Coarse sand, or builders' sand has relatively large particles, especially compared to the fine sands used for sandboxes. Of the organic matter available for gardening, not all of them will improve clay soil. The organics also must be coarse. Avoid fine-textured material such as peat moss or the packaged manures. If possible, find a source for a ruff chopped compost or manure composted with wood shavings not saw dust. Check with your city to see if they have a compost site for leaves and such. Some areas maintain a list of people offering free manure from their stables. Just be sure it is six months old before using or incorporate in fall for spring planting.

How much? And how?
You will need to cover the area with a 3-4 inch layer of organic matter then a 3-4 inch layer of sand.
At 4 inches = 1/3 foot. Length x Width x 1/3 foot = Cubic Feet needed.
Bagged products are rarely coarse and expensive in quantity. Look for a source of bulk material. It will be measured by the cubic yard (27 cubic feet in 1 cubic yard). The general rule of thumb is that 1 cu yd will cover 80 sq ft with 4 inches.
Till the organics into the clay first. Spread it evenly then work it into 4- 6 inches of the topsoil. Next spread the sand over the clay/organic matter layer and mix again going deeper. A tiller will make the work much easier but garden forks will also work in small odd shaped spaces.

Soil Conditioners and Gypsum
Lime is calcium carbonate, used to neutralize soil acidity, and gypsum is calcium sulfate, sold as an amendment to improve soil drainage. The sulfate part of gypsum will also help to slightly acidify the soil so lime is not needed if gypsum is used.

Prepackaged Humic Acid will improve soil structure, increase moisture availability to the roots and improve general plant health and vigor. This is the productive result of a long slow compost production packaged to use in pure form. This will coat the particles increasing the effectiveness of the organics added.

Mineral amendments of large particle size, such as perlite, and pumice will provide some benefit but can also be costly depending on the size of the site.