The Different Types of Clay Soil — And How to Work With Them

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Different Types of Clay Soil
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There are several categories of soil, and due to their unique characteristics, each provides different growing benefits and different limitations. The types of soil are sand, clay, silt, peat, chalk and loam.


Clay soil is considered to be a high-nutrient soil. Although this soil can be a challenge with which to work, once you learn how to cultivate it, this soil will give you great results. It's important to know that in addition to there being different types of soil, there are different types of clay as well.

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What Is Clay Soil?

Clay soils are considered to be one of the heavier soils. The soil can hold a ton of nutrients and a lot of water due to the capillary action between the clay particles, and it takes a little bit longer to drain. Out of all the soils, clay soil has the smallest particles.


Identifying clay soil is relatively easy to do. It is sticky when wet, it can be rolled, it can be smeared easily and it can be smoothed into a shinier finish. Clay soil has a propensity to get very hard when it dries, though, which causes the clay to crack while it is drying out.

Characteristics of Clay Soil

To the naked eye, all soil may look the same, which is why people often confuse the types of soil, but there are specific ways to differentiate them. Various soils have different colors, textures and other features that make them distinct. The reason clay soil is considered to be so difficult to work with is because it has different characteristics that set it apart from the rest.


Clay has a smooth texture because of its small particle size. Compared to other soils, a large quantity of clay can be in a small space because there are no gaps, whereas soil with large particles, such as sand, has way more gaps. If the soil has large particles, this will give it a rougher texture, while the small particles in clay give it a smoother texture.

Due to clay's small particle size, the soil is very dense, and it bonds together, which is why some plant roots can't penetrate clay soil. A positive to this, though, is that clay soils are resistant to erosion. A negative is that it takes longer for clay-heavy soil to warm up after a season of cold weather.


Different Percentages of Clay Soil

There are four types of clay soil that differ in characteristics depending on the amount of clay in the soil. The different percentages of clay soil include silt soils which have 0 to 10 percent clay, clay soils with 10 to 25 percent clay, clay soils with 25 to 40 percent clay and clay soils with 40 percent clay.



Silt Soils With 0 to 10 Percent Clay

This type of soil has a propensity to form a crust, which makes the soil hard. You cannot overtill this soil because it will become very compact, and water will not be able to permeate the soil. This type of soil is generally easy to till, but you should not till this type of soil in wet conditions.


Clay Soils With 10 to 25 Percent Clay

Crusting with this type of soil can be really serious. It is difficult to till this type of clay soil because it has a low amount of clay and organic material.

Clay Soils With 25 to 40 Percent Clay

This type of soil is dark in color and must be tilled with the correct water content to be cultivated correctly. If the environment runs very dry, the clay can clod.


Clay Soils With 40 Percent Clay

Heavy clay soils need a lot of recompacting in order to be considered an optimal soil. It is very nutrient rich, but it cannot be tilled in wet conditions.

How to Work With Clay Soil

Clay soil can be difficult to work with, but only if you don't know how to properly break it down. All you have to do is break up the clay into separate crumbs, which will allow the water and nutrients to better reach the plant roots. It also makes the clay soil warmer, which will make it more malleable and easier to work with.


To break down the clay, you should add compost or Miracle Gro Organic Choice Garden Soil to loosen up the soil. It's better to work with smaller plants, trees and shrubs because they can adapt to the clay soil quicker than other types of plants.

You can also add lime or gypsum (a soft sulfate mineral composed of calcium sulfate dihydrate). Avoid adding sand soil to clay soil because it will turn the soil into a more cement-like texture. This type of texture will kill your plants because they won't get enough nutrients.



Plants That Grow in Clay Soil

When trying to figure out what kind of plant you want to put in your clay soil, know that some plants that have taproots may prosper in clay soils while other taprooted plants may not. Taproots have straight tapering roots that grow directly downward into the ground. Plants that have deep taproots that can be successfully grown in clay soil include butterfly milkweed (​Asclepias tuberosa​, USDA zones 3-9), bluestars (​Amsonia spp.​) and silphiums (​Silphium spp.​). Bluestars bloom in the spring, silphiums grow tall and butterfly milkweed is a short- to medium-height plant.


If you're growing carrots (​Daucus carota​ subsp. ​sativus​) in clay soil, you may want to grow them in raised beds. In heavy clay, carrots, which are taproots, may become misshapen or forked.

Other plants that work well in clay soil include magenta-flowered blazing star (​Liatris spp.​, zones 3-9), asters (​Aster spp.​, zones 3-10, depending on species and cultivar), goldenrods (​Solidago spp.​, zones 2-8), black-eyed Susans (​Rudbeckia hirta​, zones 3-7), and many types of ornamental grasses. All of these types of plants love full sun, but if you have an area that is filled with clay soil that doesn't get enough sun, you can plant shade-loving ferns or wild ginger (​Asarum canadense​, zones 4-6).

Best Vegetables for Clay Soil

You can grow annual vegetables in clay soil such as lettuce (​Latuca sativa​), chard (​Beta vulgaris​), snap beans (​Phaseolus vulgaris​), and Brassica crops (​Brassica oleracea​), such as broccoli, Brussels sprouts, and cabbage. You can also grow mid- and late-season sweet corn (​Zea mays​), and cucurbit crops (​Cucurbita spp.​) such as squash and pumpkins. Summer squash and pumpkins grow well in a variety of soils, but they grow especially well in clay soil that has compost mixed in. If you're feeling adventurous and have the right climate, you can also grow rice (​Oryza sativa​) in clay soil.


Different Types of Soil

Sandy soil is considered to be a light soil because there is a high amount of sand and only a little bit of clay. This type of soil has quick water drainage, which means that it is easier to work with compared to other kinds of soil. Peat soil retains a lot of moisture, so home gardeners often import this to make a base soil optimal for growing plants.

Silt soil is light, has a high fertility rate, holds moisture and drains well. If you've ever wondered what silty soil looks like, this type of soil has fine particles, so it is known to wash away quickly if you don't add a different kind of organic matter to make it compact together in clumps. Chalk soil can be a light or heavy soil because its alkalinity levels are high. The calcium carbonate or lime makes this soil more alkaline.

Loam soil is a mixture of sand, silt and clay soil. Combining all three of these soils negates the negative properties of each soil. Loam soil is known to be super fertile and easy to work with, It also has excellent drainage. This type of soil is considered a favorite among gardeners.




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