grass profile2026-10-20By The Turf DeskEremochloa ophiuroides · warm-season
Centipedegrass: the 6 g lawn that lime will kill
Generated from this page: thatch banded by tendency, roots to 150 mm, dot pitch set by the 25 mm cutting floor
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 species most often destroyed by well-meaning liming, because it wants pH 5.0 to 6.0, not 6.5.
Centipedegrass performs at pH 5.0 to 6.0, the lowest band of any species in this profile set. Apply the 250 g per square metre of lime that a bluegrass lawn would get and the turf yellows, thins and stops spreading, because above pH 6.5 the plant cannot take up the iron it needs and the soil microbes that feed it change community.
If a soil test comes back at pH 5.2, do nothing. That is the target. If it comes back at 4.8, apply 100 g per square metre of dolomitic lime and retest in a year rather than pushing for a single-step correction.
Budget 6 g of nitrogen per square metre per year, split 50:20:30. This is a quarter of what hybrid bermudagrass needs. Exceed it and the result is not a greener lawn, it is a thatchy one: centipedegrass responds to surplus nitrogen by building stolons and mat rather than leaf, and it becomes far more susceptible to large patch and to winter kill.
Yellowing in centipedegrass is almost always iron, not nitrogen. Iron chlorosis shows as yellow leaf blade with green veins; apply 2 g per square metre of ferrous sulphate and the colour returns in five days. Adding nitrogen to a yellow centipede lawn makes the problem worse.
On 100 square metres the annual nitrogen is 300 g, 120 g and 180 g of actual nitrogen across late spring, early summer and early autumn.
The band is 30 to 50 mm with a floor of 25 mm. Centipedegrass produces a stolon mat that sits on the soil surface, and cutting below 25 mm removes it. At 30 mm the lawn is dense and even; at 50 mm it needs cutting only every 10 to 14 days and tolerates a rotary mower without fraying.
Growth is slow enough that the one-third rule rarely binds. Cut every 10 to 14 days through the growing season, and cut at 50 mm going into winter so the stolons are not smothered by dead leaf.
Wear tolerance is 2 of 5 and recuperative is 2 of 5, so a centipede lawn does not take concentrated traffic and does not repair. It is a low-maintenance ground cover, not a playing surface.
Large patch is the main disease, and it is worse on over-fertilised and over-limed lawns, which is the same failure mode as everything else on this species. Winter kill follows a wet, cold winter on a lawn that carried late nitrogen, and the recovery is slow because the species spreads at 50 to 100 mm a season.
Establishment takes 16 to 24 weeks from seed at 12 g per square metre, or one full season from plugs.
Centipedegrass against the rest of the warm-season group
Because it wants pH 5.0 to 6.0. Lime pushed the pH above 6.5, which locks up iron and changes the soil biology this species depends on. Test before you lime, and only lime below pH 5.0.
Can centipedegrass be grown from seed?
Yes, unlike most warm-season species here. Sow at 12 g per square metre when soil temperature at 50 mm is above 20 degrees Celsius, and expect 16 to 24 weeks to full cover.
How do I fix a yellow centipede lawn?
Iron, not nitrogen. Apply 2 g per square metre of ferrous sulphate. If the leaf is yellow between green veins, that is the diagnosis, and extra nitrogen will only make the thatch worse.
Four field symptoms, each read back to the parameter that produced it rather than to a product. The last column is the one number that row turns on, with the threshold drawn on it.
Cutting height has been held below the species floor, thinning the stand from the centre of the lawn outwards until the soil is exposed.
Concentrated traffic along a path, at a gate or in front of a goal has worn through the canopy to soil, and the species has no rhizomes to repair it.
Drought dormancy has gone past the survival limit, four to six weeks for cool-season turf and six to eight for warm-season, and the crowns have died.
A fungal patch disease, large patch on warm-season turf or summer patch on cool-season, has killed the crowns in a ring pattern.
Grub or chafer larvae have eaten the roots under the patch, and the turf lifts away from the soil like a carpet when pulled.
A spill of fertiliser, petrol, herbicide or a concentrated dog urine patch has killed the leaf and the crown together.
Raise the cutting height to the species band: 25 to 40 mm for Kentucky bluegrass, 30 to 50 for perennial ryegrass, 50 to 70 for tall fescue, 40 to 60 for fine fescue.
Scarify or core-aerate the bare area to 75 mm depth so the seed has soil contact rather than a compacted surface.
Seed at the species rate: 15 g per square metre of Kentucky bluegrass, 30 of perennial ryegrass, 35 of tall fescue, 20 of fine fescue. Where the area is over 1 square metre, use a blend rather than a single species.
Where the species has no rhizomes, which is tall fescue, fine fescue and St. Augustinegrass, the only repair is seed or plugs. There is no parameter change that will fill the patch.
For a dog urine patch, water 25 mm immediately and leach the salts below the root zone, then reseed. Do not add nitrogen; the patch is already salt-burned.
For grubs, confirm by lifting the turf and finding 10 or more larvae per square metre, then treat; below that threshold the lawn recovers on its own.
Replace the traffic. A worn path worn again and again needs a hard surface or a paving strip, not another reseed.
Pull a handful of turf at the edge of the patch. If it lifts like a carpet with no roots attached, the cause is grubs or a root disease; if it resists, the cause is surface wear or drought.
Look for a ring pattern. Large patch and summer patch kill in expanding rings with a green centre or a green edge, which wear and drought do not produce.
Check the cutting height against the species band; scalping produces a uniform thinning across the whole lawn rather than isolated patches.
Dig a 100 mm deep spadeful at the edge of the patch and check for larvae, white fungal mycelium, or a hard compacted layer at 50 mm.
The surface stays wet: compacted soil, a thatch layer over 15 mm, or a hollow that collects water keeps the top 20 mm saturated for most of the year.
Light has fallen below the compensation point of the grass, usually under four hours of direct sun, so the turf thins and stops competing.
Soil pH has fallen below 5.5, which suppresses the grass and the bacteria that decompose thatch while moss tolerates the acidity.
The cutting height has been held below the species floor for long enough to thin the stand, opening the surface to colonisation.
Nitrogen has been below the species budget for several seasons, or above it, in both cases leaving a stand too weak to close the surface.
Soil has been compacted by traffic to the point where infiltration drops below 5 mm an hour and every rain sits on the surface.
Core-aerate to 75 mm depth at 50 to 100 mm spacing, two passes at right angles, to break the compacted layer and restore infiltration.
Scarify 5 mm in early autumn where thatch exceeds 15 mm, then overseed at the species rate; a thin stand is what moss is colonising.
Raise the cutting height to the top of the species band. In shade that means 60 mm for fine fescue and 70 mm for tall fescue, not 30 mm.
Switch the species to creeping red fescue, shade rating 5 of 5, where direct sun is under four hours. Moss tolerates shade; most lawn grasses do not.
Apply lime only if a soil test reads below pH 5.5, at 200 to 250 g per square metre on a loam, and retest after 12 months. Do not lime on the assumption that moss means acid.
Bring the annual nitrogen to the species budget in a shaded lawn, which is a third less than in full sun: fine fescue 4 to 6 g per square metre, tall fescue 8.
Improve drainage where water stands: a French drain, a surface swale, or the removal of a compaction pan at 150 to 200 mm.
Push a screwdriver into the soil. If it takes two hands and stops at 50 mm, compaction is the driver and aeration is the first action.
Time how long a 100 mm ring filled with water takes to drain. Under 25 mm an hour is compacted; under 5 mm an hour is severely compacted.
Map the sun: note how many hours of direct sun the mossy area receives in midsummer, not in spring. Under four hours, no grass species will win without changing the light.
Test the soil pH. Moss tolerates a wide range, so pH is only sometimes the driver and should never be assumed.
Read the thatch depth with a knife and ruler; above 15 mm the mat is holding the moisture that moss needs.
Nitrogen has been applied above the species budget for several seasons, producing more lignin-rich stem and stolon tissue than the soil can decompose.
Clippings have been bagged for years on a lawn that is now below 10 mm of thatch, removing the nitrogen the microbes need to break the mat down.
Soil pH has drifted below 5.5, collapsing the bacterial population and shifting decomposition to slower fungal pathways.
The lawn is a species with a thatch tendency of 5 out of 5 and has never been scarified.
Irrigation is frequent and shallow, keeping the surface constantly moist and the mat compressed rather than allowing it to dry and fracture.
Scarify 5 mm, in early autumn when soil temperature at 50 mm is between 15 and 21 degrees Celsius, with the tines set to just graze the mat.
Overseed the same day at the full species rate, 10 to 15 g per square metre for Kentucky bluegrass, 25 to 35 for perennial ryegrass, 30 to 40 for tall fescue.
Topdress 1 to 2 mm of sand-loam matched to the root zone, then water 6 to 10 mm a day for ten days.
Cut the annual nitrogen to the species budget: 15 g per square metre for Kentucky bluegrass, 10 for zoysia, 6 for centipedegrass and fine fescues.
Raise soil pH into the species band with 200 to 250 g per square metre of lime on a loam, applied in the following autumn and retested after 12 months.
Switch to mowing at the top of the species band and mulch the clippings, which returns 1 to 2 g of nitrogen per square metre per year.
Cut a 100 mm square flap of turf with a knife, lift it like a hinge and read the brown fibrous layer between the green leaf bases and the dark soil with a ruler. Do it in three places.
Push a screwdriver into the profile; if it stops in the mat before reaching soil, the layer is thick and hydrophobic.
Watch a hose test: water beading and running off a dry lawn instead of soaking in is the signature of a hydrophobic thatch layer.
Check for the crown being lifted above the soil line by parting the grass with both hands; crowns 15 to 20 mm above soil dry out in two days.
15 mm
mat depth
Broadleaf weeds2026-11-01
This row is released with the 2026-11-01 entry, and will carry the same four columns as the others.
