Creating and maintaining a lawn requires a range of operations, split between Primary and Secondary tasks.
Primary tasks are those that make a lawn out of a field:
Secondary tasks are those that mitigate the effects of managing grass for a lawn:
- Pest & disease control
- Insect larvae
Mowing grass is the most important task in maintaining a lawn but needs to be carried out frequently. How often is dictated by the height of cut (HOC) required. At one extreme is the bowling green finish with a HOC of 4-6mm that needs to be done every day or every two days in the summer if at 8-10mm. The other extreme is a lawn cut every two weeks at 50-75mm. A good quality lawn is often produced by mowing at 20mm every 2-3 days in the summer.
One of the effects of mowing is that the grass roots reduce in size the lower the height of cut. This affects other tasks such as watering.
The required height of cut also dictates the choice of mower: rotary or cylinder. High quality lawns mown at 12mm or less require a cylinder mower. A rotary mower can be used at these HOC but the lawn needs to be level and the blade kept at peak sharpness. Rotary mowers are excellent at higher HOC as cylinder mowers often just flatten the grass, but can be used if the grass is cut every other day.
One other decision to make when mowing is; should the clippings be collected, or boxed off, or left on the ground? A good quality lawn requires the clippings to be collected as they can encourage earthworm activity, increase the risk of broad leaf and grass weeds to spread., and can smother the grass. Clippings can be left on the ground on longer, rougher lawns not meant to be high quality areas of grass. It can, however, be beneficial if clippings are left on the surface for one cut per week during hot and dry weather as they can help to conserve moisture and return nutrients to the soil.
Changing the direction of mowing is essential to produce an upright growing grass and not one that develops a nap or grain, which can result from mowing in one particular direction too frequently.
Feeding your lawn is necessary if clippings are being collected as nutrients in the leaf are also removed from the plant and soil. The choice and amount of fertiliser is also dictated by the quality of lawn required by the owner and the grass species used. A high quality lawn containing fine leaved grasses, such as Fescue and Bentgrass, and mown every two days will need a good quality fertiliser containing low amounts of nitrogen applied every 4- 6weeks. A fertiliser with a NPK (Nitrogen, Phosphorus, Potassium) content of 8:0:6 is adequate for these lawns grown on soil. Sandier, free draining soil may need a higher nitrogen and potassium content with some phosphorus, eg NPK 12:2:8.
High quality lawns that are predominantly ryegrass will need more nutrients as this species is hungrier. Ryegrass, however, is hard wearing and grows quickly meaning it can withstand the wear from a well used lawn (e.g. as a children’s play area) and recovers more quickly. Fertilisers with typical NPK content suitable for ryegrass lawns are 14:4:10 or 16:4:12.
Over fertilising can cause lush growth, meaning more mowing, and weak leaf tissue that is more prone to pest and disease attack. You won’t go far wrong in applying a good quality fertiliser at 30-35g per m2 every 4-6 weeks, and regulating the amount according to grass growth.
Grass plants require water for growth processes and keeping soil moist ensures healthy grass growth. Moisture is also vital for soil nutrients to be released for plant uptake and microbes to be able to carry out their essential roles in protecting the plant from disease. The amount of water applied depends on the rate of grass growth and soil moisture content. In the UK, dry soils occur in the summer after 10-14 days of hot and dry weather, and lawns benefit from water being applied in high amounts every few days rather a little every day. This means water goes deep into the soil but to also to dry the surface that allows air to penetrate, and grass roots grow deeper using this practice.
Before we go into Secondary tasks, we need to understand the need for them. Grass is a prolific producer of organic matter in soils. The regular cycle of leaf and root growth production and replacement produces dead organic matter at the soil surface. Worms normally recycle organic matter in soils but, in the lawn soil environment, worms are not encouraged and organic matter can build up to problematic levels. This is called ‘thatch’ and Secondary tasks are used to remove and control its accumulation.
Worms are the biological tools that aerate soils, i.e. creating a link between the above surface atmosphere and the soil environment. This allows the release of CO2 from respiration of grass roots and soil microbes to be released into the air, and for air to be drawn into the soil for healthy grass growth and soil conditions. Worms, however, are not encouraged in lawns as they leave casts that are flattened when mowing that are then open areas for weed seeds to establish. Mechanical aeration can be a costly operation but is essential in producing high quality lawns, and there are different used.
- Hollow coring – the aerator machine is fitted with strong steel tubes that remove cores of thatch. This method also helps with compacted soil, with the remaining soil collapsing into the space created by removing cores of soil. This operation can be carried out once or twice per year depending on the amount of thatch.
- Solid spiking – the aerator is fitted with strong steel spikes, typically 4 inches long, that punch a hole in the soil. This method is advantageous if the surface is compacted but the underneath is in good condition. This allows surface water to drain through the surface and air to infiltrate into the soil.
Scarifying is the term used to describe the removal of thatch and surface organic matter using a machine or hand rake. This can be done on lawns in spring and autumn when the soil is moist, and the grass is growing so that it can recover. The amount of thatch removed can look dramatic but is worth the effort.
Topdressing is the term used to describe the application of a thin layer of sandy soil to the lawn surface. The material is normally applied after aeration so that it fills the holes and links with the underlying soil to avoid layers of materials. Topdressing mixes with the thatch layer preventing it becoming a solid layer of impenetrable organic matter, and it helps to keep the lawn surface smooth.
There are many reasons for unhealthy grass. Highly concentrated TurfSolv® products alleviate, restore and help the recovery from damage. We have identified the four most common causes. Insect lavae such as chafer grubs and leatherjackets. Disease, plant parasitic nematodes and fairy rings.
TurfSolv® is an accompaniment to traditional fertilisers, weed killers, moss killers and lawn fertilisers which gardeners seem to think they need without realising they may be dealing with lawn pests and disease.
Find more information on how to use TurfSolv®