Advice
RHS Help & Advice
Lawns during drought
The current British climate is moist enough for grass to grow year-round. If it browns in drought, it soon regrows when rain returns. If summers become hotter and drier, as predicted, turf grasses will be further drought-stressed at a time when water is likely to be too scarce for lawns to be watered.
During dry weather lawn grasses may start to suffer, especially once the top 10cm (4in) of soil dries out. Given adequate rain or water they will normally recover fully. However, following severe drought you may need to repair or relay your lawn in the autumn.
During dry spells in summer
Raise the height of cut in dry weather to avoid weakening the grasses. Letting the clippings fall back onto the lawn during dry spells can slow down the evaporation of water from the soil surface. But you must make sure the cuttings are small, otherwise they will lay on the grass and cause damage.
If you have to water, water the lawn once the soil becomes dry, but before the grass colour changes. If the ground is very hard, aerating before watering can aid water penetration. Watering once a week to 10 days is normally sufficient. Ensure that the water reaches a depth of 10cm (4in) after each watering; in the middle of summer 1 sq m will need only 20-litres every seven days.
Recovery after drought
After a dry summer the autumn provides an ideal time for carrying out renovation and repair. This will help a lawn recover from drought but also make it more drought resistant for the following year.
Rake up clippings that were allowed to fall to avoid a build
up of thatch (dead grass material and other debris). Heavy raking or scarification can be harmful in
most cases.- Aerate to help rain to percolate to grass roots. Aerate to a depth of at least 10cm (4in). Even with free-draining sandy soils there may be some areas of compaction.
- Before rain, apply a proprietary autumn lawn fertiliser, which will be high in phosphorous and potassium and low in nitrogen to encourage strong rooting.
- Overseed any sparsely-grassed areas using an appropriate lawn-seed mixture. Do so when the weather and soil conditions are suitably cool and moist for germination, usually in September. If drought continues to the end of September, defer sowing until late March or April, as results are often unsatisfactory from late-autumn sowings. Break up the surface with a fork and rake to make a suitable seedbed prior to sowing at a rate of 35g per sq m (1oz per sq yd). For sparsely-grassed areas, sow at half the rate.
- Do not use weedkillers in autumn on drought-affected turf. Use in spring, after feeding and when the grass and weeds are growing vigorously (usually from mid-April onwards).
- Moss may be a problem when winter wet follows a dry summer. Treat this either in spring or autumn, using a proprietary moss killer, and feed.
The future of the British lawn
Some grasses root more deeply than others, and natural swards often contain deep-rooted plants such as clovers and other legumes. Mixtures based on these may prove more drought-tolerant and sustainable.
Traditional lawns are high-input: powered mowers use energy, as does the manufacture of lawn fertilisers and weedkillers. Hand-propelled mowers and organic fertilisers such as pelleted chicken manure are better alternatives.
The question to ask is, do you really need closely-mown areas? Why not let the grass grow longer and include meadow flowers and bulbs? Or replace the lawn with a gravel garden, drought-tolerant border, groundcover plants or permeable paving.
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