Renovation of Deteriorated Lawns

New Zealand Journal of Agriculture, Volume 95, Issue 3, 16 September 1957, Page 300

Renovation of Deteriorated Lawns

By

C. WALKER,

Assistant Fields Superintendent, Department of Agriculture, Palmerston North ST is not uncommon to find that many • lawns after being established under good conditions with adequate seed of suitable species are subsequently allowed to degenerate into run-out swards dominated by flat weeds, clovers, and coarser grasses. However, a run-out lawn can be brought back into first-class condition within a relatively short period by spraying to control weeds and by suitable manuring. THE degeneration, of many lawns can be traced to one or more of the following causes: — 1. Manurial treatment is entirely neglected and semi-starvation sets in. This leads to a weakening of desirable species, with corresponding increases in weeds. 2. Faulty manurial treatment, which encourages coarser grasses and clovers at the expense of the fine turf species. Such treatments include compost, blood and bone, phosphate and lime, and nitrate of soda. 3. Irregular mowing, resulting in some smothering of fine species by excessive growth from time to time. Any or all of the above can cause fairly rapid deterioration to set in, but equally speedy recovery can be attained by the adoption of proved methods of lawn management. Where a lawn has become infested with unwanted species and appears to lack sufficient fine turf components there is no need to despair; nor is there any need for expensive reseeding, unless bare ground has to be covered. From research work on deteriorated lawns over the past 3 years the following procedure can be recommended: — 1. Elimination of clovers and weeds: As a preliminary to other work the lawn should be sprayed to eliminate both clovers and flat weeds. Two fluid ounces of the low volatile ester of 2,4,5-T per 100 sq. yds. of lawn and the potassium salt of MCP at 1 fl. oz. to the same area will destroy all existing clovers and weeds. These sprays

are best applied in spring or autumn when good growth is taking place. It may be necessary to repeat this spraying 6 months later; if so, half the above quantities would suffice for the second spraying. If moss is also a problem, it can be destroyed by . spraying with sodium pentachlorophenate.' This spray is sold commercially under various trade names, and i pint would be required per 100 sq. yds. where the stock solution contains 21b. sodium salt of PCP per gallon. 2. Manurial treatment: Immediately after spraying, the lawn should receive a dressing of sulphate of ammonia and superphosphate mixed in a ratio of 3:1 at loz. per square yard. This should be repeated quarterly in the first year, and then at 6 monthly intervals. Under no circumstances should other fertilisers be used in bringing a lawn back, as most of them encourage weed growth or coarser grasses and clovers. Fertiliser treatment can begin at any time and does not need to follow spraying unless the time is appropriate for spraying.

3. Reseeding: Reseeding should be restricted to bare patches only. Where necessary a mixture of 2 parts of chewings fescue to 1 part of browntop sown at joz. per square yard will usually be adequate. Where there is existing fine turf, even if apparently run-out and very thin, manurial treatment alone will be sufficient to develop a good sward without the addition of any seed. Work done on this aspect of lawn renovation has emphasised the futility of trying to establish seed in an existing sward, even where grooving has been done to aid seed establishment. Associated with spraying and suitable manuring there should be regular and moderately close mowing to enable fine turf species to get maximum light and to weaken the coarser grasses that thrive under lax cutting. With this procedure a run-out lawn can be brought back into first-class condition within a relatively short period.