Earthworms

A structural quality performance standard which states the maximum amount of earthworm casting present, as a percentage, covering the surface being maintained. The standard might also state the maximum number of earthworm casts counted, rather than area covered. Earthworms provide significant benefits to a grass sward, but can also severely impact on playing quality, especially of golf greens, bowling greens, cricket squares and capping of sand-slit drainage systems where installed on winter games pitches. An appropriate acceptable maximum percentage would be given to balance benefits with disadvantages.
The number of earthworm casts per m2 will vary throughout the year because the prevailing weather and environmental conditions, hot-cold and dry-wet, significantly influence the zone or layer of activity the earthworms inhabit. This can also be used as a threshold figure for an IPM programme.