Soil Basics: The Difference Between Soil and Dirt

Did you know that soil and dirt are not the same thing? In their excitement to get seeds planted, gardeners tend to overlook this fact. I’ve heard it said that “a garden is a reflection of the quality of its soil”. So it stands to reason that a garden with beautiful soil will produce beautiful plants. So, what is the difference between soil and dirt?

Knowing the difference between soil and dirt can make all the difference in a productive garden and one that barely grows.  I’m about to take you on a journey that will explain everything you didn’t know you needed to know about soil!  So grab your double soy latte’, a note pad and sit a spell while I tell you what soil is, why it’s important and what it does for plants and the earth. I’ll also cover the different types of soils and how you can improve bad soil.

The Basics of Soil:

Soil is actually a mixture of organic matter, organisms and a few other things all teeming with life! It’s a renewable product. It regenerates itself but it does so at a very slow rate. Have you ever walked in a forest and noticed all the leaves, plants, twigs and other debris scattered on the ground? If you move all that stuff aside, you’ll see that the forest floor is alive! There’s stuff growing underneath all that organic matter. And it’s decomposing or “regenerating” all on its own. Without anyone lifting a finger! Makes a person wonder why we break our backs every spring tilling up a garden! But that’s a topic for another time.

How is soil different from dirt?

Dirt may originate as soil but that stuff on your clothes and under your fingernails is not soil. It’s dirt. Dirt is the name for displaced soil. Because it’s been displaced, dirt no longer has the ability to support plant life. I think back to my childhood years, being told to remove my shoes at the door after playing outside. I don’t ever remember hearing my mother fuss at me for tracking in “soil”. Mud, dirt and snow, yes…but never soil!

Just sayin’.

 

 

What does soil do?

Among other things, healthy soil not only gives us healthy crops, it also gives us clean air and water. Most people know how the earth’s water cycle works. Without going into too much detail, water gets evaporated into the air where it condenses and falls back to the ground as rain or snow. Soils job is to filter out the impurities before that water is again evaporated back into the atmosphere. In fact, soil has several specific functions. One is regulating water run-off from rain, snow melt and irrigation. Another is filtering and detoxifying organic and inorganic materials. Soil helps filter gases like carbon dioxide and methane. But most importantly, for gardeners anyway, soil provides support for growing plant roots. So you could say that soil literally supports life!

What are the different types of soil?

There are three different types of soil; sand, silt, and clay. Each soil has its own personality…or rather, it’s own soil structure. But the biggest difference is the size of the particles that make up each type. Each type also differs in color, amount of nutrients and ability to hold water.

You will never see a soil that is all one type. For example, you’ll never find a soil that is 100% silt or 100% clay. Different soils will have different combinations of all three types. But the best soil combination for growing plants has equal parts sand and silt with just a little clay. Even though the clay is minimal, it contains nutrients that the plants need to grow. This perfect soil is called loam and is what smart gardeners strive for. Loam is also rich in humus. Humus is what’s left over after organic matter decomposes. That’s a good thing!

Why is soil structure important?

Absolutely! Soil structure will tell you a lot about how a soil will behave. If you grab a handful of soil and squeeze it, what happens? Does it stick together slightly or crumble like a cake? Does it sift through your fingers without sticking at all? Or does it hold together like a glob of old play-dough?

Since we’ve covered loamy soil and you now know that it’s the best stuff for your garden, you’ve probably guessed that this is the type that will crumble like cake. This crumbly soil will support roots and allow water to move through it but not so fast the plants don’t get a chance to drink. It can hold water without becoming a puddle.

Sandy soil allows water to move through quickly. Really quickly. When it moves through that fast, it takes all the nutrients with it. As a result, plants aren’t properly hydrated.

Clay soil doesn’t allow water to run through at all. And when it’s dry, it becomes hard and compacted, like cement. If water can’t get through, it’s a sure bet that roots can’t either.

A word about compacted soil…

Compaction can destroy soil structure by closing soil pores. It happens when people walk, run or drive on it repeatedly. And it’s worse when all this activity happens on wet soil. Compaction can slow down or stop water and air from moving through the soil. It also limits root growth and won’t allow the soil to drain properly. In fact, it may pool at the surface, creating a big puddle.

I have used weed block fabric in my gardens for several years. I recently read an article that suggested weed block can also lead to soil compaction since it doesn’t allow for water or air movement through the soil. Go figure! But since it’s great at preventing a sore back while pulling weeds, I’m not about to give it up just yet. I’ll discuss the pros and cons of weed block in another post.

 

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What causes soil to be different colors?

Just as soil structure tells us how a soil will behave, soil color can tell us what the soil contains. For example, red, yellow or orange/rust color soil usually indicates a large amount of iron oxides. Too much iron is toxic to plants. Too little iron and a plant won’t be able to produce chlorophyll, which helps a plant take in sunlight.

White soil indicates salt content or soil that has been leached of nutrients. A soil with little or no nutrients can’t support or sustain plant life. Grey or greenish-grey soil develops when soil retains water for prolonged periods. While this kind of soil usually applies to wetlands and swamps, it isn’t much good for growing anything. Except for rice….it’s good for that.

Brown or black soil indicates a large amount of organic material. Organic material is the bomb when it comes to soil. This is what you want for your plants!

How can I get healthy soil?

Adding organic matter in the form of compost or aged manure, mulching, growing cover crops and adding worms is the best way to improve the health of your soil. Adding chemical fertilizers will only add certain nutrients and do nothing to maintain your soils long term health. Organic matter can supply everything your plants need and will improve most any soil. Making your own compost is an easy process but may take some time. It’s as simple as layering brown leaves, straw, grass clippings, manure and food waste, one on top of the other and giving it a good stir. Keep the pile moist but not wet and turn it regularly. Plus, you can keep adding to the pile until it’s the size you need. Once organic matter decomposes, it will look just like regular soil. And it can provide all the nutrients your plants need as well as improve soil structure, soil texture and the capacity to hold water.

Compost options:

If turning a compost pile isn’t on your agenda and you’re in no hurry to use it, try the lazy man’s way of composting. Remember the forest floor example I used earlier? Simply gather your kitchen scraps, spent garden plants, grass and leaf cuttings into a pile and leave it alone. You can keep adding to the pile as needed and you’ll need to keep it moist. But keep in mind that it will take twice as long to decompose. I suggest finding an out-of-the-way place to start your pile so it’s not visible to visitors. Another option, if you have chickens or other critters that forage, is to let them have access to the pile…they’ll turn the compost for you!

How to amend soil the right way:

Plants like tomatoes and peppers are considered “heavy feeders” They use up all the nutrients available in the soil during their growing season. So even if your soil is fine now, you’ll need to stay on top of replenishing those nutrients with compost, manure or any of the other options previously mentioned. 

Bad soil that is gradually improved each year can grow plants indefinitely. It won’t happen overnight or even in one growing season. Nor is it recommended. You know the old saying…too much of a good thing is still bad. A soil test before you start amending will tell you what your soil needs. Guessing what your soil needs or going whole hog right off the bat with amendments could cause your soil conditions to swing too far in the other direction. Don’t be in a rush to improve your soil because even imperfect soil can still grow something. Once you get your soil where it needs to be, do your best to maintain it. You can do this through no-till gardening, crop rotation, cover crops, avoid walking on the beds and continuing to add organic matter and mulch as needed. 

 

 

Are earth worms good for soil?

Most definitely! Earthworms are an important part of the soil ecosystem. In fact, they are one of Mother Nature’s recycling crews. They convert dead leaves and plant debris into readily available nutrients. They also help aerate the soil and convert organic matter into humus. Try this…dig up about one square foot of garden soil, six to eight inches deep and count the worms you find. If you have a bunch, you’re in good company. If there are only a few, or none at all, you need to give them some organic matter to feed on. Like in the movie…”if you add it, they will come”.  Okay…maybe not those exact words but you get my meaning. If you’re not seeing any worms at all, you can purchase earth worms to add to your garden. I strongly suggest red wrigglers…they’re the king of compost earth worms!

Final thoughts…

Soil does so much for the earth but is often overlooked. In fact, there would be no life on earth without soil! Over time, it is expected that soil will lose its nutritional ability to feed the earth if the nutrients are not regularly replaced. This could result in fruits or vegetables that are lower in nutrients and flavor than they were in years past. 

Soil is an ecosystem that is teeming with billions of bacteria, fungi and other microbes. This ecosystem is what soil health is based on…the ability to sustain life for plants, animals and humans. Healthy soil is vital for more than just growing a garden…it’s essential for the growth of future generations!

I’m not a soil expert. But I do a lot of research to make sure I’m giving my garden the best possible chance to produce. I want that for you too!  A good question to ask yourself is “Do I want to waste time, money, seeds and plants on hoping that my garden will succeed?” Think about that before you you plant.

Are you a soil expert? Did I leave anything out? Maybe you have a question about soil. If so, leave a comment below. If you agree or disagree with anything you’ve read, let me know. I’m always interested in getting a different perspective.

Until next time,

lisa