HOW TO IDENTIFY YOUR SOIL TYPE
Recently, we've noticed more and more people are interested in growing their own food. Since growing yummy vegetables requires a fair bit of care, there's also been an increase in discussions about dirt. If you've tried to grow anything in soil that's hard and compact, or really sandy and dry, you'll understand what we mean. Soil quality is essential for everything you grow, not just vegetables. In general, we're lucky to have pretty high-quality soil in Indianapolis.
If you're having trouble growing anything in your garden, it's important to know what kind of soil you have, so that you can add the right elements to improve it.
WHAT IS SOIL MADE OF?
Soil has five main elements:
gas
water
organic matter
minerals
living organisms
It's a complete ecosystem, and if any of the elements are missing, your soil may struggle to sustain plant life. With that said, soil that would be uninhabitable for some plants can be perfect for others.
All of these elements are important to achieve that "black gold" that gardeners around the world covet.
WHAT ARE THE DIFFERENT TYPES OF SOIL?
There are six different types of soil, but across Indiana, we have 3 of them: clay, sand, and the most sought-after soil type; rich loam. That "black gold" loam is what makes our state such an agricultural powerhouse. We all want that perfect loamy soil, but not everyone is lucky enough to have it. Here are the characteristics of the six soil types:
Clay soil is mostly made up of very fine mineral particles. It holds water well, almost too well, and can quickly become hard and compact. Compaction makes it difficult for plant roots to grow, and its water retention can cause plants to rot or drown. Clay is slow to warm up in the spring, and when it finally drys out, it cracks. However, clay is very nutrient-dense.
Chalk soil is rocky and stony with large particles. It drains extremely fast and doesn't hold many nutrients. You'd typically find chalky soil where the underlying bedrock is chalk or limestone. It requires copious watering and fertilizing. It is very alkaline due to the high content of rocks and stones.
Peat soil is very high in organic matter and has decent drainage, but it can get waterlogged. Peat is quite acidic, so organic matter takes a long time to break down. It is also generally low in nutrients. Peat soil is quite spongy in texture.
Silt soil is similar to clay, although the particles will be slightly larger. It drains better than clay and is quite nutrient-dense, though it still retains quite a bit of water and can get very compacted.
Sandy soil is made of rather large mineral particles. It does not hold on to nutrients or water; it drains exceptionally fast. It doesn't compact well and provides little to no stability for plants.
Loamy soil is that ideal black gold; it's a balanced mixture of sand, silt, and clay. The ideal ratios are 40% sand, 40% silt, and 20% clay. Together, these three elements help the soil retain nutrients, hold onto just the right amount of moisture for plants, and provide structure to stabilize plants while allowing roots to grow freely.
HOW DO I KNOW WHAT KIND OF SOIL I HAVE?
Identifying your soil type is easier than it sounds. Try these at-home tests to find out what type you have.
THE SQUISH TEST
This is a great test for beginners. Pick up a small bit of wet soil and squish it between your fingers.
If it feels gritty, you probably have a high percentage of sand.
If it feels sticky and lumpy, you probably have a high clay percentage.
If it feels smooth and almost slimy, you probably have a high silt percentage.
THE BALL TEST
This test is great for identifying soils with high clay content. Mix a small handful of your garden soil with a bit of water to make it evenly moist, and then try to roll it into a ball in your hands. Once you've made a ball, let it sit for about 10 minutes to dry a bit, and then pinch it between your fingers.
If it mostly sticks together when flattened, you have high clay content.
If it crumbles easily and falls apart in your hand, you've got high sand content.
If it breaks up into a few smaller chunks that hold together, you have high silt content.
THE JAR TEST
The jar test takes a little more effort, but it's more precise. It's also an interesting science experiment that your kids can do with you.
Collect soil from a few different areas of your garden, mix it all together and spread it out on a flat surface.
Let it dry until the texture is quite crumbly.
Pick out any roots, large stones, or big chunks of organic matter.
Scoop about 1 cup of soil into a glass mason jar, add a squirt of liquid dish soap, and then add water. Leave around an inch of room at the top of the jar to allow for some movement.
Screw on the lid and shake your jar vigorously for 2-3 minutes.
Set it somewhere undisturbed and let it settle for a minimum of 24 hours, up to 48 if you think you have high clay content.
As the soil settles, it will layer itself. The bottom layer will be sand and gravel. The next layer will be finer sand, the third layer will be silt, and the top layer will be clay. Once it has all settled, you can measure how thick each layer is and figure out what percentage of each element you have.
Now that you've identified what your predominant soil type is, you can work on improving it. If you'd like, you can further test your soil to determine its acidity. You can pick up a pH testing kit at our garden center to find out if your soil is more alkaline or on the acidic side. We've got all different kinds of materials to help you achieve the optimum balance for loamy black gold soil.
There's one amendment that will benefit any soil, and that's organic matter. If you've been composting, work that into your garden soil. Organic matter improves everything.