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Backfilling, Trees, Shrubs & Herbaceous Borders

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This specification applies to the installation (planting) of various types of plant materials, including bare root, containerized, and balled and burlapped stock.

Fairfield's compost meets the requirements of the BSI PAS 100, which ensures we meet the minimum standards and the specification limits on stones, weed seeds and physical and chemical contaminants.

The specification below sets out additional requirements for the use of compost in planting pit preparation:


Units of Measure

Recommended Range


pH Units (1:5 water extract)

 7.0 - 8.7

Moisture Content

%mm of fresh weight

35% - 55%

Organic Matter Content

% dry weight basis

25% minimum

Electrical Conductivity

mS/m (1:5 water extract)

200 maximum

Particle Sizing

% m/m of air-dried sample passing the selected mesh

99% pass through 25mm screen

90% pass through 10mm screen

C:N Ratio


20:1 maximum



Meet BSI PAS 100* Criteria

*Fairfield's compost has a pH level of 7

Using Composted Material, and Soil Analysis

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