Assessing Growing Medium
How Assessing Growing Medium & Root Depth Is Used in PQS
Growing Medium (Rootzone) Assessment
🗝️ The growing medium — often called the rootzone or top soil— is the natural soil or imported rootzone the grass is growing in. PQS evaluates:
- Depth of the growing medium (measured to at least 150mm depth)
- Contamination (stones, debris, black layer, anaerobic areas)
More advanced assessment may include;
- Soil texture (sand/silt/clay balance)
- Soil structure (compaction, aggregation, pore space)
- Organic matter levels
Why it matters
🗝️ A good growing medium:
- Encourages deep, strong rooting
- Allows rapid drainage but retains some moisture
- Improves nutrient availability
- Reduces compaction and surface hardness
- Supports consistent ball behaviour
🗝️ A poor growing medium leads to:
- Weak rooting
- Waterlogging or hardpan formation
- Slow drainage during PQS infiltration testing
- Thin or stressed turf
- Uneven playing quality
How it is assessed in PQS
A core sample or soil profile sample (as pictured) is taken to visually inspect:
- Colour (dark = organic matter / black layer, light = sand-dominated)
- Layering (e.g., thatch layer, compacted pan, topdressing bands)
- Rooting zones
- Soil texture and friability
📝 The sample provides qualitative data that helps explain PQS performance measurements such as hardness, traction, and infiltration.
Root Depth Assessment
🗝️ This measures how deep and dense the grass roots grow into the soil profile.
In PQS testing, assessors typically record:
- Maximum root depth
- Functional rooting depth (where roots are most active)
- Root density and distribution
Why it matters
💡Root depth is one of the best indicators of turf health and resilience:
Deep, dense roots provide:
- Better drought tolerance
- Improved nutrient uptake
- Faster recovery from wear
- Stronger anchorage (improves traction)
- Improved surface stability
- Enhanced infiltration and reduced waterlogging
Shallow or sparse roots lead to:
- Weak turf that tears easily
- Soft, unstable surface
- Poor drainage
- Increased disease risk
- Difficulty maintaining grass cover in high-wear areas
How it is assessed in PQS
📝 From the extracted soil profile sample, the assessor identifies:
- Depth of visible live roots
- Colour and health of root mass
- Whether roots have penetrated through key layers
- Restrictions caused by compaction, thatch, or anaerobic zones
Root depth findings are compared to benchmark expectations for sport type:
Football/Rugby: 80–150mm desirable
Cricket outfields: 100–200mm desirable
High-wear community pitches: 60–80mm minimum acceptable