Soil Tips

  • Does your soil have good drainage? Here’s a simple test:

             Dig a hole about 30cm deep and fill it with water. When it has emptied, fill it again and time how long it takes to empty again.

             Less than 1 hour indicates very good drainage

             1-2 hours indicates good drainage

             2-3 hours indicates fair drainage

             3-4.5 hours indicates poor drainage

             If it takes more than 6 hours it is probably not suitable for planting trees.  Ref:  RFC Brisbane Branch newsletter Dec 2001 N/L

  • Jude Lai showed us a technique that his father in China had used in the preparation of earth for planting. A fire was made using large logs and other wood, then soil mixed with grass was added on top of the still burning wood. This heap continued to slow combust for weeks, depending on the amount and size of the logs. The resulting “Burnt soil” had a really good structure and contained a lot of charcoal and carbon, with the addition of some manures/compost this makes exceptionally fertile soil.  Ref:  RFC Brisbane Branch newsletter June 2001
  • Don Ellison says that by using weedmat he bought from Bunnings (not the commercial type you get elsewhere) that his passionfruit vines grew three times as fast as those without. The mat is about a metre wide so cut off a square and slash it in a cross in the centre. It stops water evaporating and heats up in winter.  The reason he prefers the Bunnings type is that it is more open.
  • In a recent edition of The Weekly Times there was an article on huge variations in soil test results for phosphorous from three different laboratories which has prompted Australia’s industry watchdog to act. Apparently one of the Landcare Offices found Olsen P results from three soil testing labs in Victoria and South Australia delivered results which varied by 250% yet all three labs are listed as being proficient at testing for Olsen P with the Australian Soil and Plant Analysis Council. They believe it was the methodology used as results should not vary by more than + or – 20%. ASPAC certifies labs as proficient by sending each of them three batches of four soil samples over 12 months. However, the tests are not blind with each lab knowing the sample is part of the ASPAC proficiency test. Consequently some industry commentators say there is a real risk of labs putting their best lab technicians on to test the ASPAC samples and repeat them if they think the results are not right.  Ref: STFC newsletter Oct Nov 2009 - Sheryl Backhouse