Getting to the root of things

One of the most important parts of the garden is the soil. Its texture – sandy, loam or clay – and pH will determine what will grow there and what won’t, while issues such as compaction and poor drainage should really be dealt with as soon as possible. 

I’m currently studying soil as part of my Horticulture course and needed to take a sample from one area of the garden, but decided to test eight areas overall to see if there was any variation. I’ve also read that you can take samples from different areas, mix them and test them… but again, I was really curious to see if the pH changed, particularly between the orchard, the section of the back garden that’s home to camellias and a rhododendron, and the front garden (also home to an acid-loving rhododendron and a camellia).

Carrying out a texture test on the soil.

We purchased a pH testing kit last weekend and I spent part of today (a nice sunny afternoon) working my way around the orchard and the rest of the garden, taking samples from different areas and testing them for soil and pH – and quietly thanking the unknown person who had installed four different taps in our garden, as it’s a reasonable length and I’m still recovering from a broken and dislocated toe, so I didn’t want to do too much walking between the tap and the testing sites.

The last time I did any soil sampling was years ago, back when I was studying soil science during my third year of my Environmental Science degree. Still, kneading balls of wetted soil to determine the texture brought back memories of testing different soils in the lab and out in the field.

Carrying out a pH test on the soil.
Adding some lime, which raises the pH, to the sample… just out of curiosity.

The pH results didn’t surprise me too much: between 6 and 6.5 for six sites in the back garden, which is also home to a couple of camellias and a rhododendron, and between 5 and 6 in the two sites I tested in the front garden. This was once home to a pine tree and I had been wondering if the needles had had any effect on the soil – I’ve added pine needles to potting mix when planting strawberries and blueberries (more acid-loving plants) in pots.

However, the texture tests revealed that the soil throughout the garden is actually a sandy loam. This did surprise me, as I had been expecting a heavier soil; Lithgow was once home to a pottery (the area it was in is called Pottery Estate), so I’d half been expecting a clay loam.

One of the many patches of moss in the lawn in the back garden.

The other reason I’d been expecting a heavier soil is because we have a lot of moss growing in the lawn, which can be a sign of poor drainage according to Peter Cundall’s book The Practical Australia Gardener (page 68: ‘Moss in the Garden – How to Eliminate it, or Use it’). I’m now guessing that the soil might be slightly compacted (it was slightly difficult to dig into for the samples) and I may need to add more organic matter to any future garden beds.

This does work reasonably well with my plans for no-dig gardens… and with the huge amounts of fallen leaves the orchard will generate for us. I’m now also looking at lists of plants that love acidic conditions and sunlight for the front garden…

Further reading: Peter Cundall, 2007. ‘The Practical Australia Gardener – seasonal tasks using sensible organic methods. Penguin Random House Australia (first published in 1989).