on May 21, 2026
You don't need a lab. You don't need a kit. You don't need to know your nitrogen levels to the second decimal.
For most home gardens, a five-minute check with nothing but your hands, a trowel, and a watering can will tell you ninety per cent of what you need to know. Whether to plant. Whether to feed. Whether to fix something underneath before you put anything new on top.
Here's the test. One minute each. Five tests. Five minutes.
Minute 1: Look
Dig a small handful out of the top 10 cm of soil. Lay it on a flat surface. Look at it.
Healthy soil is dark. Crumbly. Holds together in loose pieces rather than dust or hard lumps. You can see different sizes of particles, bits of broken-down organic matter, maybe a tiny root or two.
Unhealthy soil is pale, dusty, or compacted into hard cracking lumps. Uniform colour all the way through. No visible texture. No organic matter.
Colour is the easiest signal. The darker the soil, the more organic matter and biology it usually contains. Pale soil that crumbles to powder is hungry.
Minute 2: Smell
Pick up that same handful. Smell it.
Healthy soil smells alive. Closest comparison is a forest floor after rain, or a damp compost heap that's working properly. That smell is a compound called geosmin, produced by certain soil bacteria, and it's the signature of a working microbial community.
Unhealthy soil smells like nothing. Or worse, it smells sour, ammonia-like, or stagnant. A no-smell soil is biologically silent. A sour smell usually means the soil is waterlogged and anaerobic.
Trust your nose. It's the cheapest soil test you'll ever do.
Minute 3: Dig
Grab a trowel and dig down 15 to 20 cm in a few spots around the bed. Count the earthworms.
Healthy soil in south-east Queensland should turn up two or more earthworms in a 20 cm spadeful during the cooler months. Closer to five or more in a properly active bed.
Unhealthy soil turns up nothing. No worms in three different spots is a real signal. Worms vote with their bodies. If they're not there, the food underneath isn't either.
Note: in the hottest part of summer, worms move deeper than your trowel will reach. So this test is most useful from autumn through to spring.
Minute 4: Squeeze
Pick up a handful again. Squeeze it firmly in your fist. Open your hand.
Healthy soil holds together in a soft ball that breaks apart cleanly when you poke it. It has structure, but the structure isn't permanent. It crumbles when disturbed.
Sandy or stripped soil falls apart immediately when you open your hand. No ball. No structure. It runs through your fingers.
Compacted clay soil holds together like wet clay (because that's what it is). Doesn't break apart cleanly. Stays in a hard lump.
The middle ball is what you're after. It tells you the soil has enough organic matter to hold structure without going stiff.
Minute 5: Water
Find a spot in the bed away from your plants. Pour a cup of water onto the surface from about 20 cm above. Watch.
Healthy soil absorbs the water within about 30 seconds. The surface darkens evenly. No pooling. No running off to the side.
Compacted or biologically depleted soil pools the water on top for a minute or more. The water runs off before it soaks in. The soil is essentially closed off.
This last test is the practical one. It tells you whether your plants are actually getting the water you give them, or whether most of it is running off into the drain.
Reading the results
If you got four or five healthy results out of five, your soil is in good shape. Mulch, feed, keep doing what you're doing.
If you got two or three, you've got biology issues. The structure is patchy, the microbes are running thin, and the soil is asking for input. This is the most common result in Australian backyards that have been on synthetic fertilisers for a few seasons.
If you got zero or one healthy result, the soil is functionally exhausted. Plants will struggle no matter what you put on top. You need to rebuild from underneath.
What to do next
The fix in all three cases is the same idea, just in different doses. Feed the biology underneath. Synthetic fertilisers strip what little is left. Worm castings put microbes, mycorrhizal fungi, and slow-release nutrients back where they belong.
If you want the longer beginner's guide on what worm castings actually are and why they work, start here. For the application side, here's the practical how-to.
Nano Soil's Probiotic Soil Conditioner is 1.8kg of pure worm castings, enriched with mycorrhizal fungi, made in Brisbane.
Five minutes today. Better soil by next season.
