5 to 5cm or so) may be useful for relieving light overall I surface compaction or capping, to improve penetration of rain or sprinkler I irrigation, but where there is deeper and more general compaction choose I tools which will penetrate to at least 3m (8cm), and preferable 4 to 6in(io to 15cm). An ordinary garden fork is quite suitable for the purpose. On heavier clayey soils use a hollow-tine fork. Each tine removes a core or plug of soil, expelling it onto the surface at the next penetration. This allows the soil to expand. After sweeping up the cores top-dress with a sandy soil mixture, working this into the holes with a besom or brush. This leaves the turf pierced with permanent cores of free-draining, aerated, sandy soil into j which new roots rapidly develop. This technique has little value on sandy soils but can be practised with benefit on heavier soils every three or four years. Deeper and more general aerating should be done in September, when the soil is moist. Localized areas of compaction can be relieved at any time during the spring or summer, irrigating thoroughly afterwards. Repeat at four- or five-week intervals where there is continuous heavy usage. Тор-Dressing Top-dressing is the name given to a mixture of loam, sand and well-decomposed organic matter applied in moderate amounts to the surface of a lawn. It is also the term used for the operation itself. ] Top-dressing helps achieve and maintain a true even surface by eliminating minor irregularities; on poor or difficult soils the surface layer is improved so that there is better rooting in of grass runners and stolons giving a denser, healthier turf. Sand or peat alone can be used but too frequent use of peat can build up a spongy surface which holds excessive moisture at the surface in wet conditions and is difficult to re-moisten following dry periods. Heavy dressings of sand can build up into an unstable surface layer. A simple and basic formula for a top-dressing mixture is 3 parts (by weight) loam, 6 parts sand and 1 part granulated peat. Finely sieved leafmould or well-decomposed garden compost can be substituted for the peat content: sand should be lime-free with a particle size of 0.2 to 0.5mm. Apply by broadcasting with a shovel at the rate of about 41b per square yard (1.8kg per m2), increasing up to 6 to 71b per square yard (2.7 to 3.2kg per m2) where there are considerable irregularities. Work well into the base of the grass using a "lute" or the back of a wooden rake. On a level surface distribution will be even; on an irregular surface bumps will be left clear with proportionately more deposited in hollows. Do not apply too heavily, or finer grasses will be smothered. Top-dress in early autumn as part of the autumn programme, but delay for a time if the grass is still growing strongly. Mow the lawn before applying the top-dressing in settled, dry conditions. It may take two or three years to obtain a true even surface; once achieved there is no need for further top-dressing except on difficult soils.