Problems & treatments

Moss. Almost never the actual problem. Moss colonises lawns that are shaded, compacted, badly drained or mown too short — kill it and it comes back within two seasons unless you fix the reason. We treat the moss and then tell you which of those four it was.

Thatch. A spongy brown layer above the soil. Over about 12mm it stops feed and water reaching the roots. Mechanical removal only — see the Lawnbook piece.

Chafer grubs and leatherjackets. Root-eating larvae. The visible damage is usually birds and badgers digging for them. Treated with nematodes, and the timing matters more than the product — how to tell which you have.

Compaction. Clay soil, foot traffic, a trampoline in the same place for four years. Water sits on the surface after rain. Hollow-tine aeration, usually twice a year for two years.

Dry patch. Irregular areas that stay brown however much you water, because the soil has become hydrophobic. A wetting agent fixes it; more water does not.

Weeds. The easy one, and the one people worry about most. Selective herbicide clears broadleaf weeds in three to four weeks. If they come back every year the answer is a thicker sward, not a stronger spray.