Soil testing without a kit
Learn your home’s soil composition to help your garden thrive.
> BY JOE P HASLER
To make their fertilising plans for the season, many home gardeners turn to store-bought soil-testing kits, which can help them determine whether to add chemicals such as nitrogen, phosphorus and potash. While these tests are helpful for large-scale farmers, soil scientists say they’re often unnecessary for backyard gardeners. For example, nitrogen levels can fluctuate daily, requiring retesting throughout the growing season to gain information you can act on.
Soil scientist John Parsen says the most common problems can be identified with very low-tech methods. “Many kits assume there’s a problem with the soil, and come from a perspective of ‘how do I fix it?’. “In fact, most home soil is probably okay and needs only minor improvements to complement what you already have.” Parsen’s advice?
Simply get your hands dirty.
The soil check up
1 Ribbon test
Moisten a handful of soil to putty-like consistency. Gently squeeze it between your fingers, creating a “ribbon” of dirt. If the soil is too gritty to hold a shape, it’s sandy. If the ribbon breaks after reaching a length of 2,5 to 5 cm, your soil is loamy or evenly proportioned with sand, silt and clay. That’s perfect for most garden plants. If the ribbon reaches 6 cm or longer, it’s clayey. Parsen says that adding compost to sandy or clayey soil will create a healthier loam over time.
2 Worm count
In the potential planting area, dig a 30 x 30 x 30 cm hole and put the soil on a tarpaulin or piece of plastic sheeting. Sift through and count the earthworms. A dozen indicates flourishing life underground. If numbers are lacking, add organic material to boost the subterranean environment.
Parsen says a shortage may also indicate chemical pollutants. Concerned urban growers can take soil samples with an auger (right) and send them away for testing: ask your garden centre for advice or visit www.soils.org.za and click on “Links” to make contact with your nearest university with a soil science or agriculture faculty.
3 Drain test
Fill your worm-count hole with water. If it takes longer than an hour to drain, the area could have a drainage problem, and you may want to plant elsewhere. PM