Thursday, 28 November 2013

If you insist on having a Lawn as part of your indigenous garden then please make sure it is not a weed patch

 Your lawn certainly does not need to be premium turf but please ensure that it is healthy, it need not be a monoculture of one grass specie, but please ensure that it is not a weed patch full of exotic weeds

This article has been written specifically for the management of warm season grasses in  Durban, South Africa. The terms lawn and turf apply to one and the same thing grass plants of various species that have been cultured in a particular unnatural manner due to the misguided sense of order of modern man
which dates to no earlier than the 16th century and in its present form probably no longer than a hundred years.

Following the establishment of your lawn, the focus now changes to Turf Management.  Contrary to popular belief, Turf Management does not need to be a daily chore, although the amount of work necessary depends on the quality of lawn desired.  For many only minor changes to existing Turf Management practices is all that is required to have a top quality lawn.

Grass species best suited to growing conditions in Durban
The most commonly planted and certainly the two most suitable lawn grasses that are found growing in Durban are the two local indigenous grass species;

Cynodon dactylon the dominant grass in Durban is a fine grass which is the only grass suitable for hard wearing sports turf and other high use areas.

Berea Grass Dactyloctenium australe, is a very versatile grass that is well suited to both domestic as well as amenity horticulture. Berea Grass grows best in full sun on sandy soils where it is found growing naturally in the coastal dune systems, it will also do well in medium shade.

Your lawn does not need to be trimmed neatly all of the time from time to time you can let it flower and seed this will bring in the most unbelievable number of bees of many species.

Country Club Paspalum vaginatum  This local indigenous grass is a salt tolerant specialist grass that has been developed for golf greens and which is generally not suitable for domestic lawns.

Cynodon Hybrids. There are also specialist fine leafed hybrid grasses requiring specialised care to perform well which have been developed from Cynodon dactylon and Cynodon transvaalensis species for golf greens and are generally not suitable for any other use.

The following foreign grass species are also found growing in Durban in small amounts. 
Please avoid using these foreign invasive and destructive grass species because we have very suitable local indigenous grasses.

Buffalo Grass Stenotaphrum secundatum known elsewhere as St. Augustines Grass is an alien invasive grass from the Americas which I do not recommend planting in Durban.

Kearsney or Carpet Grass Axonopus compressus as it is known elsewhere is a tropical grass from the Americas which is also an alien invasive grass from the Americas which I do not recommend planting in Durban.

Kikuyu Pennisetum clandestinum  this is a highly invasive very destructive foreign grass which does not like the hot humid conditions at the coast but does grow well in the cooler inland suburbs of Durban.

Mowing is the most important task undertaken.  Make sure the mower blades are kept sharp at all times as blunt blades will damage the grass leaves and give a poor quality unsightly cut. The commonly adopted approach to grass cutting is that of scalping the lawn at periodic intervals, (i.e. setting the mower too low) this causes serious damage to turf grasses, thus negatively affecting the quality of the lawn.  This practice in conjunction with insufficient or inappropriate fertilizing is one of the main reasons why lawns become sparse and dominated by weeds. A mower with blunt blades, especially a rotary type mower that cuts lawn by impact does considerable physical damage to the grass leaf which increases the grass plant's susceptibility to fungal and bacterial attack, increases moisture loss and gives the lawn a ragged white look. The best mowers to use on fine turf are well set reel mowers that slice cleanly through the grass leaf. Reel mowers give the finest cut and also roll the lawn smooth they are used primarily on golf greens and fairways, sports fields and bowling greens and by the home gardener who demands a high quality lawn.  Under no circumstance whatever should a lawn ever be mowed with an edging machine, (weed eater) because the cutting action is by impacting the grass blade with a blunt instrument, the nylon cord, which tears the grass leaf to shreds leaving a very untidy ragged finish. The second reason for not using and edging machine to cut lawn is that it is impossible to accurately control the correct cutting height the usual consequence is the lawn is cut far too short and very often the sensitive growing tips of the grass plants are totally destroyed opening up an avenue for the invasion of weeds which eventually completely take over and replace the grass cover.

Mowing Height
Each turf grass species has its own optimal mowing height for the use it is being put to.  When mown regularly within the correct height range, a uniform dense turf cover is encouraged which limits the opportunity for weeds to establish.  Conversely, mowing too low or too high thins the turf, which allows bare areas to develop, in time these areas become colonized by weeds. As a rule of thumb for home lawns a height between 25- 40 mm gives the best results. In shady areas the lawn should be allowed to grow a little longer. Short lawns look neater however the grass plants have shorter roots systems, and suffer more environmental stress. This means that short lawns require very careful management, in particular watering, fertilizing and mowing. Increasing the height of cut under stress conditions in particular during summer drought periods is a good management practice, which helps to maintain a healthy lawn.

Mowing Frequency
The rule of thumb is to remove no more than 25% of the grass plant leaf at any one time.  Scalping (removing all or most of the leaf and the growing points, as well as parts of the stem) severely damages or kills the turf grass plants thus allowing weed seeds the opportunity to germinate and to establish themselves in the lawn, this bad management practice provides the opportunity for weeds to better compete.

Mowing height and frequency will depend on:
The specie variety of grass as well as the time of the year (for example, growth is more vigorous in Autumn/Spring than in winter.
Mowing height and frequency is dependant on the use the lawn is to be put to as well as personal preference.
Mowing a little less frequently and raising the height of the cut during hot periods will reduce moisture loss.

The more frequently the lawn is mowed the better the quality of the lawn produced
If you wish to improve the appearance of the lawn for a special event, the best result will be achieved through an increase in mowing frequency not a lowering of height.  This may involve mowing up to three times per week.  This increase in frequency should begin at a minimum two weeks before the event.

Lawn clippings
Grass clippings can be left on the lawn after cutting, rather than removing them this applies in particular to domestic lawns on sandy soils. The clippings decompose quickly, returning nutrients to the soil within weeks of mowing. The macro elements contained within the clippings comprise of nitrogen, phosphorus and potassium at ratios of 5:2:3, respectively. Trace minerals are also present. The amount of nitrogen returned to the soil is as much as 88 kg/ha. Since nitrogen is the most expensive component of all lawn fertilizers, it pays to leave clippings.
Clippings also enhance the habitat for beneficial soil micro-organisms. Earthworms ingest the clippings at night, further increasing the aeration and fertility of the soil, and maintaining a base that allows the lawn to feel springy when walked on. If the grass clippings are removed, worms will migrate to other more favourable habitats this will negatively influence soil structure and fertility.
Whether to return or remove the clippings or to return them to the soil is a personal choice. 

I personally believe that it is a good environmental practice to allow the grass clippings to remain onsite.

There are good reasons in favour of both options.

Where clippings are returned to the soil the advantages include:

Mowing is easier
Mowing is (generally) cheaper in particular where contractors are employed
Nutrients are recycled to the lawn
It is a good environmental practice to do so
The lawn will not require to be fertilized as often.

The disadvantages of clipping return include:
The finish may not be as good
Disease could under certain circumstances be enhanced
On weedy lawns, weed seed is returned to the soil
Where clippings are too thick, the turf can become smothered allowing weeds to establish.
A possible Increase in thatch build-up. (Thatch is an accumulation of dead leaf and stems and shoot mass encountered on well used lawns that experience large amounts of traffic, thatch reduces or prevents the penetration of water into the soil and a reduced gas exchange to the root zone). Thatch is seldom encountered on home lawns.
Leaf cuttings could be blown into swimming pools

The grass plants, which make lawns as with all living organisms, require nutrients to grow and to be healthy. Regular applications of fertilizer supply the required nutrients thus ensuring vigorous healthy grass plants and a top quality lawn. The nutrients essential for growth within the soil are nitrogen (N), phosphorus (P), potassium (K) and iron (Fe). As a result of lawn culture certain essential plant nutrients are lost to the system, due to the removal of grass clippings, leaching of nutrients out of the root zone as well as losses of nitrogen to the atmosphere. Nitrogen deficient grass is yellow-green, and lacks vigour. Nitrogen produces deep green leaves, rapidly growing leaves and shorter roots. Phosphorus facilitates metabolic functions plus energy storage and use. Potassium is used to create cell components, and it helps regulate respiration and transpiration. It helps the plant grow, withstand environmental stress and resist disease. Fertilizers should contain N, P and K. where possible select a balanced fertilizer that contains a mixture of slow and fast release N. This allows the lawn to green up with 2-3 days and stay green for several weeks. Iron can be used to control moss and some broad-leaved weeds. Iron darkens the grass, making it appear greener without stimulating growth. In Durban with it´s high average rainfall and generally sandy berea red soils leaching of plant growth nutrients is generally very high so frequent preferably monthly low application rates of fertilizer are recommended. This does not only benefit the lawn producing far better growth but the annual use of fertilizer is reduced considerably

Always use a balanced lawn fertilizer.
Greening of Lawns
To give the lawn a good green colour without boosting the growth rate water or spray with a ferrous sulphate solution at the rate of 50 to 150 grams per 100 square metres of lawn. This will have a superb greening effect on the lawn, only apply when there is plenty of moisture available for active growth. Ferrous sulphate at these concentrations can be applied at any time of year as long as good soil moisture is available and the temperatures are not excessive.
Increase the concentration to 150 to 200 grams and not only will it have a good green-up effect but it will also harden the turf making it more resistant to disease and fungal attack. This is a very common practice on sports turf in late autumn and winter in Europe but seldom if ever encountered here in South Africa.

Frequency of application
The general rule is that frequency should be such that turf density and colour is maintained.  Obviously the exact programme will be influenced by many factors, such as:

grass type
atmospheric conditions
soil type, i.e. sandy soils will require lighter more frequent dressings than loam/clay soils
whether clipped are moved or not
amount of wear received (high traffic areas require more regular dressings)
If your lawn begins to turn yellow then it may need fertilizer for chlorophyll synthesis to occur.
However, as with most things, over fertilizing may result in problems (thatch, disease) and ultimately an unhealthy and difficult to maintain lawn. Over fertilizing with high nitrogen fertilizers of Kearsney Grass Axonopus compressus can lead to yellowing and the eventual death of the grass.
As a general rule two main applications of a good balanced lawn fertilizer with a higher potassium (K) content in the spring and autumn and if needs be one or two light applications of a balanced fertilizer with a higher nitrogen (N) content during the Summer months will produce a high quality lawn, however be careful too much nitrogen applied in summer may stimulate lush growth and encourage diseases.

Fertilizer Application
Apply fertilizer uniformly to avoid variations in growth and the risk of killing the grass due to toxic doses. Never apply fertilizer by hand always use a mechanical fertilizer spreader, i.e. a rotating disc spreader, which can be purchased from most hardware and garden shops.  For even application when applying the fertilizer divide the fertilizer into two batches, and apply half in one direction and the rest at right angles to it. If using a spinning disc or broadcast spreader, set the machine to half the application rate and make adjacent runs at half the distance apart of the machine's spread.

1. Always apply a known weight of fertilizer to a known area at the recommended rate, to avoid fertilizer toxicity.
2. Avoid applying fertilizer in the heat of the day.
3. Never apply fertilizer to a lawn that is under moisture stress.
4. Always irrigate after applying fertilizer

To prevent corrosion to metal parts of the applicator, wash the applicators with water after use.
The use of irrigation is primarily to supplement deficiencies in rainfall, a good automatic system can be used to maintain the lawn in top condition throughout the summer.  However, care is required, as poor irrigation management in particular over watering can create problems.

Watering during establishment
As a general guide irrigate early morning again for a short period at mid-day and again in the early evening
There are cost effective water timers and sprinklers available from retail outlets.
When irrigating, completely wet the root zone rather than just wetting the surface.  To avoid wastage, water should be applied at a rate so that ponding is avoided.  This may require several short bursts of watering rather than a single irrigation cycle.

Watering after establishment
Turf grass is a relatively high user of water. Enough water to completely wet the root zone must be applied at each watering. The frequency of watering will be determined by atmospheric conditions and the water retention properties of the soil. Irrigate before the first signs of wilting to avoid damage to the lawn. A rule of thumb for top quality irrigated lawns is to apply 25 mm per week during the summer months

Weeds are all unwanted plants that will colonize your lawn if you engage in bad management practices, for instance, incorrect mowing height and frequency, insufficient or inappropriate watering, the lack of regular applications of or too much fertilizer, or to a much lesser extent insect or disease attack.
When the turf looses its density and uniformity an open sward develops that leaves it wide open to colonization by unwanted weeds. Weeds in turf grasses can be very effectively controlled with the use of herbicides and by implementing a good turf management program.
To correctly apply herbicides is a skilled job that requires a good understanding of their application and mode of action as well as the correct identification of the particular weed to be eradicated.  There are many herbicides that can successfully remove weeds, both broad leaf and weed grasses from lawns, however if you are not experienced in turf care, consult an expert.

When applying herbicides always:

Read the manufacturer's instructions on the label
Follow all safety and application instructions
Wear safety equipment as required
Use a calibrated sprayer

Insect Pests
The most frequent encountered insect pests in Durban are;
Army worm and lawn crickets that require specific insecticides to eradicate.

As with weed control, there is a large range of insecticides on the market. 

When applying insecticides always:

Read the manufacturer's instructions on the label well
Follow all safety and application instructions to the letter
Wear safety equipment as required
Use a calibrated sprayer
Consider neighbours and the environment
Always use the less toxic option
When in doubt always consult an expert.

Ecoman Sports Turf and Lawn Expert

I have considerable experience with establishing and managing both warm season as well as cool season grasses which has been gained in Durban, South Africa, Wilhelmshaven, Germany and Auckland, New Zealand.
Sports Turf Construction Experience
My sports turf construction experience includes the construction of many sports fields for football, rugby hockey and cricket, golf course greens, bowling greens, turf wickets in Durban, South Africa over a period of more than 25 years mostly while working for the Durban Parks Department, which were all planted to warm season grasses in particular Cynodon dactylon varieties. I also constructed and renovated a number of football fields and rugby fields in New Zealand.
Amenity Turf Construction Experience
Most of my amenity turf construction experience comes from over 28 years constructing and maintaining parks and gardens for the Durban Parks Department, I also gained valuable experience as a private contractor constructing parks and establishing cool season grasses mostly for the North Shore City Council in Auckland New Zealand.
Sports Turf and Amenity Turf Maintenance Experience
Most of my sports turf and amenity turf maintenance experience comes from the maintenance of a large number of parks, sports fields, road verges etc that were  under my direct care as a horticulturist then later as a horticultural manager during the 28 years that I was employed by the Durban Parks Department
Domestic lawn Establishment and Maintenance Experience
My domestic lawn establishment and maintenance experience has been gained on warm season grasses in Durban and on cool season grasses in Wilhelmshaven, Germany and Auckland, New Zealand. My first experience with domestic lawn care was gained as a young child helping my father do his annual spring treatment of our own domestic lawn up until today where I still do all my own lawn care including the cutting of my own lawn. I have also cared for lawn for commercial clients in South Africa, Germany and New Zealand over a period of over 40 years.
For a number of years I over seeded portions of my own domestic lawn in Durban in winter with cool season grasses to maintain a lush green lawn in areas that Cynodon dactylon had been planted.
Academic Achievements

Article written by Michael Hickman on 28 November 2013

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