Understanding Soil Types for Gardening

How to Identify Your Soil and Why It Matters

Healthy soil

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The three basic soil types are clayey, loamy, and sandy soils. Loamy soils are the ideal. The other two present challenges for irrigation. So it is important to find out what kind your plants are growing in.

But how do you find out which soil type you have? Although there are more sophisticated ways to acquire this information, here is the simplest way to find out. It literally involves taking matters into your own hands.

Test by Trying to Form a Ball of Soil

  1. Pick up a marble-sized chunk of moist soil and roll it between your thumb, forefinger, and middle finger, as if trying to shape it into a little ball.
  2. With a clayey soil, your rolling will be successful: you'll end up with a ball the size of a marble.
  3. With sandy soil, your attempt at forming a ball will be completely unsuccessful; it will fall apart.
  4. With a loamy soil, your attempt will show some promise, but ultimately fail; the ball will fall apart once you leave off applying pressure.

Two Other Kinds of Soil

Note also that what I have provided is just a thumbnail sketch, so to speak, suitable for the general gardening public. A soil scientist would present a much more extensive break down of what the ground under your feet is composed of. There are other categories of soil, as well. For example, the Royal Horticultural Society (RHS) lists:

  • Silty soils
  • Peaty soils 

It is easy to remember what these two soil types are like if you associate them with geographical features with which you are perhaps familiar. If you have ever explored along a river bank, then you have probably encountered silt. When you try to roll it into a ball, you will fail; in the process, you will become aware of its silky texture. For peaty soils, think of a peat bog. Such bogs are wet and rich in organic matter. The soil there is also mucky, right? It is too loose to form a ball out of when you roll it between your fingers.

How Soil Type Affects the Way You Water Your Plants

Again, loam is ideal; the other soil types will be problematic and will especially impact how you water your plants. Here's a brief look at some of these problems.

  • Sandy soils are sieve-like. They dry out quickly and so require more frequent watering than do clayey soil types. You will waste water on sandy soil types if you apply too much all at once since the water will percolate quickly through the porous earth, right past the root zone. Once water passes the root zone, it is useless. For plants in sandy soil types, program the timer for your garden irrigation to release water over several short periods.
  • The problem with a clayey type is just the opposite: water does not percolate quickly enough through it. Plants in clayey soil types should also be watered over several short periods—but for a different reason. You need to give the water time to soak into the earth. If you water too much all at once, water just runs off and is wasted. Because clayey soil types retain water well, not only can you get away with watering less frequently, you positively should water less frequently, lest you drown your plants’ roots.
  • Silt is prone to compaction.
  • Peat may be fine for plants that like wet soil, but its water content is too high for many plants. Its pH level is also an issue for many plants, being too low, which means it is too acidic

How to Improve Your Soil

The problems with peaty soil are different from the rest. You will have to provide better drainage to turn ground composed of peaty soil into a gardening space hospitable to a wide variety of plants. That is an important first step because most garden plants do not like "wet feet." Once you have accomplished that, you can work on raising the pH level over time by applying garden lime (but do not believe for a moment that the change will take place overnight). In the meantime, you can grow acid-loving plants in such areas.

So what can you do to improve a sandy, silty, or clayey soil? You can improve these soil types by mixing in compost. Compost loosens up clay ground sufficiently to allow water to percolate through faster, while it retains enough water to counteract the "sieve effect" that plagues sandy soils.

You do not need to spend your hard-earned money on buying compost (although it is, in fact, sold in bags for those who have little time and/or no space for a compost bin). Nor is it hard to make it yourself.

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  1. Glen, Charlotte, and Tiffanee Boone. "Does Your Lawn Or Garden Need Lime?". Pender County Center, NC Cooperative Extension, 2020, https://pender.ces.ncsu.edu/2020/03/does-your-lawn-or-garden-need-lime/.