Swardwrightparameter bench23/24 entries released
Swardwright parameter bench
Species profiles, operations and field symptoms, all reduced to numbers you can measure: cutting height, nitrogen rate, tine spacing, irrigation.
Two axes, set the numbers first
Species × cutting height
Three ways in
Grass profiles
One species per page. Cutting height, nitrogen, tine spacing and irrigation, plus the parameters those four are derived from.
Operations
One job per page. Working depth, spacing, the window it belongs in, and how to calibrate your own machine to it.
Symptom reading
A symptom read back to the parameter that produced it. If the reading does not fit, the parameter is what changes.
Four readings
Most recent releases
Broadleaf weeds: reading the indicator species before reaching for a spray
Most broadleaf weeds are reporting a condition rather than causing one. Dandelion and plantain report compaction, clover reports low nitrogen, buttercup reports poor drainage, sorrel reports acidity…
Lime and pH: rate per 0.5 unit, and the species that must not be limed
Lime is the cheapest long-term improvement you can make to a lawn, and the most commonly misapplied. The rate depends on the soil texture and the buffer capacity, not on the pH alone, and there is a…
Buffalograss: the native lawn that needs 3 g of nitrogen
Buffalograss is a North American prairie species that runs on 3 g of nitrogen per square metre per year and 10 mm of water per week, with no summer irrigation at all once established. It is also…
Scarifying: measuring thatch and taking it off in millimetres
Thatch is not a cosmetic problem. Past 15 mm it becomes a hydrophobic mat that sheds water, harbours disease, and holds the crowns above the soil where they dry out. The method is to measure the…
Centipedegrass: the 6 g lawn that lime will kill
Centipedegrass is the lowest-input warm-season species available: 6 g of nitrogen per square metre per year, 30 to 50 mm cut, and a tolerance for acid soil that nothing else here has. It is also the…
Moss: fixing the moisture, light and pH parameters rather than killing the moss
Moss is a symptom, not an invader. It grows where grass cannot: wet, compacted, shaded, low-pH, thin. Chemicals that kill moss leave bare ground that moss recolonises within a season unless the…
Colonial bentgrass: the 10 mm lawn that needs a reel mower
Colonial bentgrass is the only species here that will hold a genuine 10 to 20 mm cut. It also has the shallowest roots in the set at 80 to 120 mm, the fastest thatch build-up, and a hard requirement…
Irrigation: deep soaks, ET replacement and deliberate deficit
Watering a lawn correctly comes down to two numbers: how much reaches the root zone in one application, and how dry the soil is allowed to get before the next one. Deep infrequent soaking grows deep…