What's the Dirt?

by Mark Bigej

Have you ever stopped and wondered what is in your dirt? It is probably not the topic of many conversations unless you have a problem with your landscape plants or drainage, but the truth is that the components that make up your soil make a big difference in how successful you are as a gardener. Your soil is your best guarantee for a successful garden and healthy plants. To begin to improve your soil, it would help to understand more about the basics of soil makeup.

All soils are made up of a combination of soil particle types. There are three main types of soil particles – sand, silt and clay. Each varies in size and function in a healthy soil. Too much of any one soil particle creates a challenge for the gardener. The soil we all dream of having in our garden would contain a healthy balance of the three types with some organic material mixed in.

Sand

Sand is the largest soil particle. Its shape is typically round and smooth, and doesn’t adhere easily to other soil particles. When sand is mentioned, most of us think of the type of sand we find in a child’s sand box. The sand particles most commonly found in our soils are much smaller than that, but are large relative to the other soil particles.

Imagine sand particles being like differing sized rubber balls. If you put these in a glass, you would be able to look in and see a lot of space between the balls. In the soil, these relatively large spaces are called "macropores" and serve as area that air can occupy.

While these spaces are large in soil terms, they would not be large enough to see with the naked eye. Air is vitally important for a healthy plant’s root system. Not having enough air to a plant’s roots causes the dreaded root rot diseases so commonly seen in our area.

Having too many large air spaces in your soil also has its drawbacks. The spaces air can easily occupy are difficult for water to occupy, which can cause problems in the warm summer months. It is also difficult for nutrients to adhere to sand particles, so fertilizers can easily be leached through a soil containing primarily sand.

Silt

Silt is the second largest soil particle. Its shape is irregular with a rough texture. On a larger scale, a silt particle might look like different sized balls of rumpled aluminum foil. If you put a number of these balls into a glass and look at it, you would see a combination of small and large spaces between the balls. Again, the large spaces would be the macropores. The small spaces are called "micropores". Micropores are the spaces in the soil that water occupies.

In a silty soil, you have a combination of macropores for air, and micropores for water – a good combination. A slight amount of nutrients will adhere to silt particles. The nutrients that adhere to the silt can be used by a plant’s roots as they grow near it.

Clay

Clay particles are the smallest of the soil particles. They are flat in shape and relatively smooth in texture. Legos would be a good analogy for clay particles. They are flat and lock tightly together. The only spaces between clay particles are small micropores - no room for air, only water.

Clay soil is often dreaded by gardeners. It easily becomes saturated with water and packs tightly. One good attribute of clay

particles that is frequently overlooked is its ability to hang on to nutrients. This is great news for plants. The clay particles hold on to vital nutrients, making it easier for plants to find what they need for healthy growth.

Organic Material

Organic material is any material that is living, or was once living in our soil – most commonly some type of plant. Organic material’s form is ever-changing as nature’s bugs and micro-organisms are constantly breaking it down.

Organic material can provide a soil with air and water spaces (macropores and micropores), nutrients, and the ability to help soils retain those nutrients. Most importantly it is a host to millions of living creatures vital to any healthy soil. Because organic material is constantly breaking down in the soil, it is important to routinely add it to the soil, whether it is in a living state like a crop or added as something already breaking down like compost.

What kind of soil do you have?

How do you improve it?

The soil you will find in your garden is a combination of all three soil particle types and compost. The big question is – in what proportion? If you have too much of any one component, your gardening experience can be less than enjoyable. Typically our best suggestion to improving your soil, no matter the type of soil will be to add compost.

If you find you have a soil where clay dominates, the best thing you can do for your soil is add compost. The organic material you mix in will help break up the tight clay particles, adding much needed air spaces to your soil. At the same time, the compost will provide millions of living organisms that your soil is likely missing due to the lack of air amongst the clay.

Likewise, if you find you have a soil where sand dominates, adding compost will greatly help the soil structure. The compost will help provide some water and nutrient retention, keeping down the watering and fertilizing needed to have your plants thrive through the summer.

If you aren’t sure what type of soil you have, bring a sample into Al’s. Our experts can take a quick look at your soil and help direct you on how best to improve it. We’ll help you get your foundation into condition and you’ll be excited to see the natural improvement in your landscape and garden.