Waterloo Community Garden Soil Analysis

As part of a grant from South Sydney Waste Board, Sydney Environmental and Soil Laboratory carried out soil tests in community gardens in the Board’s area in mid-2000. These are the results for Waterloo Community Garden. They are presented here to give commuity gardeners an idea of the information a professional soil analysis discloses.

Test results—garden soil

Cation analysis

  • sodium – low to good
  • potassium – low
  • calcium – slightly elevated
  • magnesium – adequate.

These were considered good results.


The test indicated a high concentration of 135.6 mg/kg.


Test results indicated a high concentration at 429.6ppm. (This was the highest lead concentration found in any of the community gardens tested. Continuing to add organic matter to the soil would reduce the translocation of lead into plants).

Acidity/alkalinity balance

  • 6.5; slightly acidic – good.

Total organic matter

  • 7.89% dry weight.

Total organic carbon

  • 4.51% dry weight.


“The soil is not ideally balanced.

  • “The phosphorus level is excessive for almost all situations, therefore refrain from adding further P (phosphorus) sources, including manure, until it falls to a more acceptable range, ie 50 mg/kg.
  • “The potassium level is low and may be improved with a suitable K (potassium) fertiliser such as potassium sulphate at the rate of 5-10g/square metre. Increase K containing materials in the compost such as banana skins, fruit and vegies”.

Waterloo Community Garden – SOIL ANALYSIS

The soil conditioner and fine mulch analysis disclosed:

Acidity/alkalinity balance

  • pH 7 (neutral).


  • ok salinity level.

Nitrogen level

  • Good.

Total organic matter

  • 34.32% dry weight – good.

Soil wettability

  • Slightly hydrophobic (water repellent).

E.coli count

  • (MPN)/g – 4

Salmonella species

  • Not detected.

Soil toxicity index

(a measure of the soil’s harmful effect on plant life)

  • Good results.

Visible contaminants

  • glass – low
  • light plastic – slightly elevated
  • stones – ok % of stones.


“The compost has a reasonable pH, EC (a measure of salinity) and organic matter level as well as excellent concentrations of nitrogen and phosphorus which is expected to contribute positively to a wide range of exotic plant species such as fruit and vegetables.

“The only slight area for concern is the wettability result which can be overcome with the use of a wetting agent. Are you adding lime to your compost? Cease, if so”.

Waterloo Community Garden Soil Test by:
Sydney Environmental and Soil Laboratory

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