Most gardening books and blogs advise you to have your soil analyzed by professional soil testing services, which you should. The analyses you get back, depending on what test you pay for, will tell you what kind of soil you have, and some nutrient results (mostly as N [nitrogen], P [phosphorus], and K [potassium]).

I would pay most attention to your organic matter content, and what soil texture they say. These will tell you what kind of soil you’re working with, and what work may need to be done to make it better, such as adding compost, mulches, and doing a bit more observing of the animal visitors to your garden.

There is a free/cheap way to test soil texture (plus smell and colour) yourself. All you need is a shovel and some water (any will do, whether it’s bottled water, garden-hose water, or whatever you like to use), and a lack of fear of getting your hands dirty (don’t do this with gloves; best done with your bare hands).

Here’s what to do:

1. Dig a clump of soil out, and grab a small handful about three to six inches down below the surface. If you feel brave enough, you can dig down to a foot or so, just to see what your soil is like further below the surface.
2. Take a little bit of water and start massaging the clump in your hand.
3. Assess what it feels like.
   • Does it feel coarse and grainy, or very fine, or somewhere in the middle?
     • If it feels coarse, you have sandy soil. If it feels somewhat grainy but not overly course, your soil is silty. If the texture feels really smooth and fine, you have clay. Soils can be a combination of these (see the triangle diagram below).
   • Does it fall apart in your hand, or can you roll it up in a ball?
     • If it falls apart or cannot make a ball, likely you have sandy soil. Clay soils can be easily rolled up in a ball. Silty soils somewhat, but tend to fall apart fairly easily.
4. Take some of that clump and wet it a little more. Next, rub it between your index finger and thumb so that you’re forming some form of ribbon.
   • If you can easily form a ribbon, you’ve got a clay-type soil.
   • If you cannot, you could have loam, silt, or sand.

Next, take a bit of soil from that hole and smell it. (Try not to get any up your nose!) Does it smell nice, or does it smell a bit rancid and sour? Nice-smelling soil is good. If it stinks, you’ve got some work to do.

Have a look at the colour of your soil. What does it look like at the top three to six inches? What about a foot (or two) down? Do you have much of a dark layer? Is it a thick layer several inches deep or very thin?

Light-colored soil indicates little to no organic matter layer (your topsoil). Dark soil usually is a good sign of high organic matter (if it stinks to high heaven, that’s a different story). Organic proponents claim that if your topsoil looks like chocolate cake (as opposed to black), it’s ideal.

Here are four good resources to help you see your soil’s colours:

Soil Colour | Queensland Government

Munsell Soil Colour Guide PDF

Soil Colour | NZ Soils

Google Image Search Soil Colours

When you’re starting a garden or are just outright curious, looking at the physical properties of your soil is always a great place to start.

Another piece to add here, while you’ve got that hole dug, is to look at the roots of the plants already there. How far down do they go? Do they hit a “compaction layer” (you’ll easily find this when you dig further down in the ground), and go sideways, or do they continue going down? If you have this hard layer with roots going sideways instead of down, you’ve got problems.

Break a plant off and look at how the soil attaches to the roots. Does a lot of soil attach itself to the roots, or does a lot of it come off? What do the roots look like? Are there many offshoots and tinier roots, or does it look like there is not much? Be worried if there’s not much room to look at.

Finally, look at the soil, especially when you’ve taken that first shovel out. Do you see certain “breaks” or soil layer cracks that look like they’re going horizontally rather than vertically, or not? Horizontal isn’t good; it means “plating,” which indicates soil compaction.

When you’re doing all this, remember to take pictures!! This gives you a reference of what you started with and what problems you need to work on. It’s also good to have just in case you have questions for other veteran gardeners or soil scientists who can help you out, and you need to show them your findings.

Taking a look at the physical properties of your soil is a great place to start. But where to next? The next posts discuss the biological components and why they’re important. This is a key, seemingly heretical divergence from the historical demand to focus on the chemical (synthetic fertilizers and pesticides) over the biological (bacteria, fungi, protozoa, nematodes, micro-arthropods, etc.) component.