Sandy Loam Soil 101: Everything You Need to Know


You’ve figured out what you’re going to plant and where you’re going to plant it. Now, you just need to sow your seeds, water your garden and wait for results! If only it were that easy. Believe it or not, what you plant your seedlings in is just as important as where and when you plant them. Sandy loam soil might be a good option.

You may have heard of loam soil and figure it’s just dirt. However, as you start to dig deep, you’ve discovered that there’s something called sandy loam soil, which seems like it would be loam soil but with sand.

Digging even deeper, you learn that loam isn’t just dirt. It consists of a bunch of things. And, how much there is of each thing determines what you can grow and how well it can grow. There’s more to loam soil in general, and sandy loam soil in particular, than just being a pile of dirt.

What Is Sandy Loam Soil?

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Technically, sandy loam soil is soil for gardening. It consists of sand, silt, and clay. To be specific, sandy loam soil is made up of 60 percent sand, 30 percent silt, and 10 percent clay particles.

Yup. That’s it.

But, that’s not very helpful.

There’s a lot more to sandy loam soil than sand, silt, and clay. Plus, how do you know what you're looking at?

What’s inside

Sandy loam soil is made up primarily of sand but has enough clay and silt in it to stop your garden from becoming a beach. The clay and silt in the soil help give the soil structure, meaning it stays in place and doesn’t move around the garden. This is important because you don’t want your soil to wash away after a hard or prolonged rainfall.

Yet why include sand at all? After all, the sand does not contain nutrients for plants. The answer to that is surprisingly simple: Including sand in your gardening soil helps with drainage. Of course, you want your plants to have water. They need it to grow. However, too much water can harm plants. The addition of sand to soil helps water drain away from roots, so you don’t overwater your plants.

Types of sandy loam soil

There are four types of sandy loam soil. They are classified based on the size of the sand particles in the soil, which are measured in millimeters.

​The types are

  • ​Coarse sandy loam soil
  • ​Fine sandy loam soil
  • ​Sandy loam soil
  • ​Very fine sandy loam soil

The classification helps explain how quickly water will drain from the soil. The finer the sand, the slower the water will drain away.

So, What Is Loam Soil?

By now you’re probably wondering if sandy loam soil and loam soil are the same.

Not exactly.

Loam soil is also made up of sand, clay, and silt. However, the ratio is slightly different than the ratio for sandy loam soil. Specifically, loam soil is less than 52 percent sand, between 7 and 27 percent clay, and between 28 and 50 percent silt.

So, as you can see, the same, but different. The question every gardener faces is, "Why should I use sandy loam soil instead of loam soil?"

Why Use Sandy Loam Soil


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The main reason you may want to use sandy loam instead of loam is because of the drainage sandy loam can provide your plants.

Let’s take tomatoes as an example. Tomatoes are the most popular plant in home gardens in America. However, they aren’t very resistant to disease. One common soil-borne illness that tomato plants can suffer from is root rot.

When your tomato plant develops root rot, your entire crop of tomatoes is ruined. The tomatoes grow and look fine -- until suddenly, they don’t. They get a brown ring as the tomato forms and then they kind of rot on the vine.

Roots that have too much water around them can suffer from root rot. While tomatoes need to grow in soil that’s moist, they also need a lot of irrigation and drainage. That is where sandy loam comes in handy.

Because of the ratio of sand to silt and clay, sandy loam does an effective (and natural) job of irrigating water away from the roots. When this happens, you lessen the chances your tomato plant will get root rot.

Caution and considerations

Using sandy loam soil to help irrigate the garden is one of the main reasons for using it. That way, gardeners don't have to do it themselves.

However, while sandy loam soil will drain water away from the roots, it can also drain away essential nutrients from your plant, starving it. You may need to fertilize your plants more than usual when you plant in sandy loam soil.

Also, sandy loam soil tends to be acidic because of the high level of sand. Too much acid can be dangerous for certain kinds of plants. When planting in sandy loam soil, make sure you regularly monitor the pH levels of your soil. If the acid level is too high, add some lime to even things out.

Identifying Sandy Loam Soil

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Surveying your garden, you look at the soil, and it looks like, well, dirt.

Well, it should. After all, it is!

However, every gardener should figure out what kind of soil they’ve got so they can plant accordingly. Depending on your soil, you’ll either need to add things to change the soil composition or plant something that will thrive in what you’ve got.

There are three ways to figure out what kind of soil you already have.

Have it tested

Scoop up a sample and take it to your local County Extension Office and have them test it. Believe it or not, this is a branch of the USDA, and they can help you out.

Touch it

Avid gardeners learn how to identify their soil by touch. You may not be a pro gardener yet, but that doesn’t mean you can’t learn how to identify your soil by feel.

Here’s how you do it. Pick up some slightly damp soil and form it into a ball. Then, examine the ball.

  • ​Sandy loam soil won’t stay in the ball shape and will fall through your fingers when you open your hand
  • ​Clay soil will hold the ball shape, and if you let the ball dry out, it will become a rock hard ball that you almost can’t break
  • ​Silt soil starts as a ball, but as you open your hand, it flattens out into a disk
  • ​Loamy soil will hold the ball shape and is soft, but crumbles easily

Water it

Don’t want to get your hands dirty? OK. You can do the water test.

Get a jar with a lid and fill it up halfway with your soil sample. Add water, so the jar is three-quarters full, then close the jar with the lid. Shake the jar vigorously to blend everything.

After about 6 to 10 hours, the soil will have settled and separated into layers.

Because it’s the heaviest, any sand will be in the bottom layer. Silt will be the middle layer and clay will be the top layer. If you’ve got more sand than silt and clay, you’ve got sandy loam soil. If there’s less sand, you’ve got loam soil.

Buy or DIY Sandy Loam Soil?

If you’ve determined you don’t have the ideal mix but want to plant species that will thrive in sandy loam soil, you can buy or make your own sandy loam soil.

Buying guide

You can purchase sandy loam soil almost anywhere. Sometimes it’s called “potting mix,” “garden soil,” or even “topsoil.” To make sure you’re getting sandy loam soil (and not loam soil), check the label for the ratios of sand to silt and clay.

Make your own

If you’re considering making sandy loam soil, you can, but it’s not as simple as throwing some sand in your dirt. Not only could it rob the soil of nutrients, but you’re also more likely to make a mess than anything.

Sand mixed with your existing soil does not create sandy loam soil. Instead, it tends to create a hard lump of dirt that you can’t do anything with.

You need to add organic compost to your dirt. That helps create the proper balance of nutrients, sand, and soil.

Add the compost (homemade or store-bought) to your garden. Work it in then wait a few days and test your soil. If, at that point, you’ve got the right composition, great. If not, add some more compost and test again in a few days.

It may take a few rounds of adding compost to get the adjustment right. But with practice, you’ll be able to create whatever loam soil you need.

Soil Is More than Just Dirt

Planting a garden (or even flowers) isn’t as simple as digging a hole, planting a seed, and waiting for results. It takes careful planning and a solid understanding of what’s in the ground to help create the perfect landscape.

Identifying if you’ve got sandy loam soil is, fortunately, not that difficult. It just takes a little practice and maybe some patience. And, once you know what you’ve got, you can plant accordingly. Or, change your soil into something that will support your gardening plans.

Either way, a solid understanding of what kind of soil you’ve got and what will grow best in it will let you plan the garden or yard of your dreams.

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Glory Lennon

Glory writes about flower gardening and other gardening subjects in addition to her serial romance novels from the Pocono Mountains of Pennsylvania, USDA Gardening Zone 5b

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