g.: 25 parts by weight superphosphate, 50 parts by weight fine bonemeal, 15 parts by weight sulphate of potash and 10 parts by weight sandy soil, and should be mixed well and applied at 2oz per square yard (55g per m2), in September. Apply lawn fertilisers by hand to measured strips, at half the recommended rate, working lengthways, then repeat the application working crossways. If using a fertiliser or linear distributor apply in parallel strips using the wheel tracks of the previous run as a guide line. Be careful to avoid overlapping, particularly if it is necessary to turn on the turf. Scarifying Scarifying is the term used to describe the removal of "thatch" from turf by the vigorous use of a spring-tine rake or specially designed scarifying tool. All established lawns have an intermediate layer between roots and leaves; a build-up or accumulation of both living and dead material, including grass stems, stolons and uncollected decaying mowings-thatch, as we call it. It gives the turf a springy resilience and a moderate accumulation of up to jin(icm) can be beneficial, acting as a moisture-conserving mulch in hot weather and giving a degree of protection against compaction and hard wear. Too great a depth of thatch can, however, impede both moisture and nutrient penetration, and in wet conditions surface drainage and aeration can be impeded, favouring the establishing and spreading of disease. If thatch is present deal with it as the first step in the autumn programme of renovation, followed by aerating, autumn feeding, top-dressing and reseeding, as necessary. Begin de-thatching in early September. Use a spring-tine rake or ordinary garden rake. If thatch is dense use one of the scarifying tools with especially designed teeth, or, for large areas, hire a mechanised scarifyer. Thatch is most usually troublesome on the more strongly acid soils or where drainage is poor, conditions in which there is reduced bacterial activity and a slow rate of decay of organic materials. If the site is wet install a drainage system. If the soil is only moderately acid, top-dressing regularly in autumn with good-quality loam should encourage more rapid thatch decomposition. If the lawn is below pH 3 apply a light dressing of calcium carbonate (ground chalk or ground limestone) during the winter months to raise the pH reaction slightly and increase the rate of decay. On light sandy soils apply at no more than 20Z per square yard (55g per m2); on heavier soils at not more than 40Z per square yard (nog per m2). Scarify (rake) lightly at intervals in the autumn to remove accumulating leaves and debris.progressive deterioration and perhaps eventual death of the turf in heavily 1 compacted areas. Compression can also prevent excess water draining away freely, giving a I misleading impression of adequacy when irrigating, or, in wet weather, encouraging the build-up of thatch and the spread of moss. Various tools are available for aerating. Wheeled models which penetrate to an inch or two (2.