Lawns: autumn care

Autumn is the time to examine lawns for signs of summer wear-and-tear, and treat if necessary. At this time of year, any treatment has time to take effect before temperatures fall and growth stops.

Apply fertiliser while the lawn is still growing strongly to improve the colour of the lawn. Credit:Neil Hepworth/RHS The Garden

Quick facts

Suitable for: Any lawn
Timing: September
Difficulty: Easy to moderate

Suitable for...

Any lawns, including formal lawns and hard wearing lawns.

Any treatment is best carried out during September, when there is time for the grass to respond before the soil temperatures fall and growth terminates for the season.

Lawn care treatments

One or more of these tasks may be required:

Scarifying

Regular raking (or scarifying as it known) keeps levels of thatch (old grass stems, dead moss and other debris) at an acceptable level. Layers of thatch greater than 1cm (3/8in) deep can impede water and fertiliser penetration.

To remove thatch, rake vigorously but carefully with a spring-tined rake. For larger areas powered tools are available as single units or mower attachments.

Note: Turf is damaged if scarified too deeply. Do not scarify in spring - opt instead for a light raking, as the lawn may not recover in summer conditions.

Aerating (spiking)

Aerating (or spiking) lawns allows better movement of air and water in the root zone. A well-aerated lawn will manage better in periods of drought or waterlogging. For an average lawn, aeration every two to three years should be adequate. Concentrate on areas that receive the most wear and those that are compacted.

Small areas can be spiked with a garden fork, spacing holes 10-15cm (4-6in) apart and deep. On clay or waterlogged soils use a hollow-tine aerator every three to four years. This extracts plugs of soil from the lawn. Hand held and motorized hollow tiners are available. After hollow-tining, sweep up the plugs and then rake a top-dressing (see below) into the holes to improve air and moisture penetration.

Top-dressing

Top-dressing is the application of loam, sand and well-rotted organic matter to a lawn in order to correct surface irregularities (a bumpy surface) and improve the texture of heavy soils. The top dressing fills the holes created by aeration. This process encourages better rooting and thicker grass.

You can often buy ready mixed top dressing. However, you can make your own from 

  • three parts sandy loam
  • six parts sharp sand
  • one part multipurposecompost or leafmould

To measure the parts, select one container such as a flower pot, bucket, or wheelbarrow – the larger the container you use, the more top dressing you will make in one go. Fill the container the number of times listed in the recipe above – so three times for the sandy loam, six times for the sharp sand and once for the compost/leafmould. Put all the parts of ingredients on a paved surface or plastic sheet and thoroughly mix them together. We measure the ingredients in parts (by volume) as they all naturally weigh different amounts and will additionally vary depending on how much water they contain when you weigh - measuring in a container ensures you get the same proportions each time.

Once you have mixed the top dressing, apply roughly 2-3kg per sq m (4-7lb per 10 sq ft). This is generally about a shovelful, but you can weigh the first load to check you've got about the right amount and then judge it by eye from then on. Work the dressing into the aeration holes in the surface with the back of a rake. The top dressing should largely disappear from view. If you see a lot left on the surface, apply less per square metre. If it all disappears into the holes, apply a little more per square metre.

Flattening

To correct bumps and troughs, use an edging iron or spade to slice through the turf and roll it back. Fork over the underlying ground and add or remove soil as needed. Replace the turf, pressing the edges together, and water thoroughly.

Problems

Lawns can suffer from a variety of fungal problems including red thread, fairy rings and take-all patch. Damage created by lawn pests such as leatherjackets and chafer grubs, as well as their predators, can be really devastating. Worm casts are also a nuisance in wet weather.

Autumn is a good time to repair damage caused by fungal diseases or pests.

Slime moulds and lawn lichens and other growths can be a real problem after a wet season.


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