Horticulture/Organic Lawn Care

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Organic lawn care is a method of establishing and caring for a garden lawn without the use of synthetic chemical inputs such as pesticides, herbicides, or artificial fertilisers. Using organic practices on a lawn is a good way to avoid exposure to potentially harmful chemicals, since among all the elements of the garden, the lawn is the part that humans come in contact with the most often, either through walking or sitting on the lawn, as well as through exposure to pets that have been on the lawn.

Managed organically, the lawn can be more than simply a green carpet and can contribute to the overall biodiversity and richness of the garden ecosystem. Organic lawns can be valuable habitats in their own right, providing a home for a variety of insects, birds and other wildlife. Indeed, by relaxing a little and allowing the grass to grow longer, we will find that the lawn becomes healthier, requires less work and even becomes more visually interesting.

Choices of grass for the organic lawn

An important principle of organic lawn care is the choosing of grasses that will suit the location and the type of lawn required, and the uses that will be expected of it. Hard wearing grass mixes can be chosen for lawns used for football and play, whilst shady spots or a fine quality ‘ornamental’ lawn would have different requirements.

Cool season grasses

Cool season grasses are grown in climates with cold winters. They are evergreen, but may go dormant in midsummer.

• Bluegrass - Fine textured, somewhat less durable than some other cool season grasses.
• Ryegrass- hard wearing perennial grass that provides a good utility lawn, withstands drought and looks good.
• Red fescue- both slender and creeping varieties of red fescue grow strongly to provide thick growth which is hard-wearing and reasonably drought tolerant.
• Meadow grasses- smooth-stalked varieties are used in blends for fine lawns.
• Other grasses- Chewings fescue, browntop bent and crested dog's tail are just some of the other grasses used in lawn seed mixes.

Warm season grasses

Warm season grasses do well in hot climates. They are green throughout the heat of summer, but will go dormant during cold weather.

• Zoysia grass
• Bermuda grass
• St. Augustine grass

Cutting the grass

The frequency and height of cut will depend on the use to which the lawn will be put. By varying them the lawn can have either a formal appearance or a more natural look. There are a wide variety of lawnmowers available, and again, these should be chosen to be appropriate to needs and circumstances. For a small lawn a hand push mower with cylinder cutting blades would be sufficient, but for larger areas it might be worthwhile to consider the benefits of power mowers, including mulching mowers. These chop the cut grass into tiny fragments which are then blown down close to the soil surface where they will quickly decompose, recycling nutrients and adding fertility to the turf. Regular mowing should only be required during the growing season between spring and autumn. Frequency will depend upon speed of growth, which will vary according to conditions, but generally speaking a weekly trim will be sufficient in early spring, increasing to twice a week later on, especially on play areas or that are required to be neater. Grass growth decreases again in autumn, and whilst the grass will still grow in winter, it isn’t usually necessary to mow, besides which conditions are often too wet.

Longer grass tends to resist drought better than short grass, and is more able to compete with weed growth. Most lawn areas can be cut to about 3 cm (1.5”), although may be shorter in play areas. Lawn mowings should never be discarded, instead should be either composted, used as a high nitrogen compost activator or used as a mulch around trees, shrubs or vegetables.

The organic gardener can recreate the traditional ‘stripe’ pattern favoured in more formal landscapes simply by using a cylinder mower or one fitted with a rear roller, but these can be a chore to maintain. Instead interest and wildlife friendly habitats can be created by mowing large lawn areas to different heights, leaving some areas to grow long with mown ‘paths’ between them.

Lawn edges can be trimmed with long handled shears, which avoid the need to bend down, and occasionally cut to a clean border edge using a spade or half-moon edge cutter.

Weeds in The lawn

Lawns do not have to consist of only grasses, indeed they will be colonised by a variety of other plant species. A tolerant attitude will see this as an asset rather than a problem to be eradicated. For example, allowing clover (Trifolium spp.) to spread will feed the grass with nitrogen. The grass will therefore grow more strongly and will be a deeper green, and will not require artificial nitrogen fertilisers. Yarrow (Achillea millefolium) will also grow very well in the lawn, and is a valuable plant in its own right, being rich in minerals and greatly enriching the compost heap. It will also increase the vigour of grass and its resistance to disease. Yarrow also has medicinal properties, and if left uncut will produce beautiful white flowers. Daisies (Bellis perennis) will also brighten any lawn, often flowering even into the depths of winter, whilst another attractive lawn flower, the dandelion (Taraxacum officinale) has a wealth of uses, all parts are edible and it has medicinal properties. In addition its deep tap root will mine minerals from deep in the subsoil to be made available via the compost heap. Other valuable wild plants that will often make themselves at home in the organic lawn include chicory (Cichorium intybus), catsear (Hypochoeris radicata), melilot (Melilotus officinalis), salad burnet (Sanguisorba minor), plantain (Plantago spp.), rough hawkbit (Leontodon hispidus) and coltsfoot (Tussilago farfara).

If however weeds do become a problem, there are organic methods which can be used to control them, including;

• Removal of individual weeds such as dandelions, daisies and plantain by hand, using an old kitchen knife or weed grubbing tool.
• Fill in holes left after removing weeds with soil or potting compost, and sow fresh grass seed into this.
• Avoid mowing too low, short grass offers less competition for weeds and can weaken it, making it easier for weeds to invade.
• Scarify to remove debris and improve conditions for grass growth.
• Ensure good drainage to prevent water-logging which will encourage moisture loving weeds and moss.

Moss can be a problem on some lawns, thriving in moist or waterlogged conditions, but also on drier soils where fertility is poor and acidity high (in particular, under evergreen trees). Moss will colonise in shady areas and spread over soil where the grass is mown too short. Moss does not withstand foot traffic as well as grasses, and trampled moss can result in bare soil and soil loss. Moss can be controlled by regular raking in spring and autumn. Bare patches should be re-seeded, and a poor lawn should be fed, for example with seaweed meal. In addition, mower blades should be raised to 2.5 cm (1”), drainage should be improved (see below) and limestone or dolomitic lime added to raise the Soil pH levels. Moss is valuable to birds as nesting material, so the wildlife conscious organic gardener may opt to leave some areas of mossy lawn for this reason.

Lawn pests

Lawn pests can include;

• Leatherjackets (Tipula and Nephrotoma spp). These softgreyishh black legless grubs growing up to 5 cm (2”) long are the larvae of thecraneflyy, and can feed upon grass roots, causing growth to become yellow and withered. They can be controlled by watering yellow areas and covering overnight with tarpaulin or sacking. Theleatherjacketss will come to the surface and can be picked off the following morning.
• Ants (Lasiuss and Myrmica spp). Ants can cause problems by building nests and mounds in the lawn, causing it to become unsightly and difficult to mow. They are very difficult to control, however pouring cold or boiling water onto troublesome colonies can go some way to reducing numbers. There are numerous species of ants, however, and many live in lawns without causing problems.
• Moles. Moles cause damage to the lawn by their tunneling actions, leaving mounds of earth which can make lawn mowing difficult and reducing valuable earthworm populations. Strong smells or the vibrations of electronic molescarerss can deter them, but trapping is the only effective permanent means of control.

Improving the lawn

The lawn is made up of millions of individual plants, and as with other parts of the garden, a healthy and fertile soil with a good soil structure is essential to obtaining good results. Feeding the lawn should not be necessary unless growth is poor, in which case an organic fertilizer such as seaweed meal can be raked in as a top dressing, or else garden compost can be thinly spread over the lawn surface. An annual top dressing consisting of a mix of 3 parts sharp sand, 1 part loam and 1 part bulky organic material on heavy soils where moss is a problem can be beneficial, as can 2 parts loam to 3 parts bulky organic material on lighter, free-draining sandy lawns. Over-fertilizing a lawn, however, can actually reduce biodiversity. Many plants, in particular legumes such as Clover, thrive in nitrogen-poor lawns, and adding nitrogen can eliminate these plants.

Acid soil conditions can cause a build up of fibrous organic matter and debris called thatch, and can also encourage weeds such as sheep’s sorrel. If the pH is below 5.5-6, lime the area to raise it to around 7. Ground limestone ordolomiticc lime evenly sprinkled over the lawn and gently raked in is the appropriate organic treatment. Repeat annually if required until the desired pH is reached. Vigorously raking the lawn in autumn with a lawn rake to remove debris and leaves is known as scarifying. In addition to preventing diseases and removing obstructions to the growing grass, this process will help the lawn to thicken up by encouraging side shoot production.

Aerating the lawn is the process of creating holes in the soil in order to improve drainage and increase air circulation, and can be particularly beneficial on compacted areas. This is best carried out in early autumn when the soil is moist. A special hollow tined aerator can be used, which takes out a core of soil about 10 cm (4”) deep, or else the soil can simply be spiked with a fork on small areas. Most lawns should not need to be aerated more than once every three years or so.

Alternative lawns

Lawns are usually established with grasses, but other evergreen species can be used. These include chamomile (Chamaemelum nobilee), which releases a sweet, apple like scent when crushed underfoot, and is thus very useful in a sensory landscape, or as a feature in the herb garden. However such a lawn will not tolerate heavy wear. The non flowering clone Treneaguee’ is especially suitable for the establishment of a chamomile lawn as it is naturally low growing. Cotulaa’ has fern like leaves and is more hard-wearing, but will not survive temperatures below −4 °C (25 °F). Another alternative, particularly where space is abundant, might be to establish a wild flower meadow. Simply leave some areas uncut and see what comes up, or else a wild flower meadow can be created by using one of the numerous seed mixes that are available that include a selection of wild flowers and grasses. Wild flowers prefer poorer soils, so should not be fertilized. Mowing is carried out infrequently, preferably on a sunny day after a period of dry weather. Mowings should be left on the ground to dry out, then shaken well in order to release any seed, but should not be left to break down as this will tend to raise fertility levels.

In shady yards, a grassy lawn can be particularly difficult to maintain. Grasses are best adapted to full sunlight, and in shade tend to be out-competed by a variety of plants, including mosses, Ground ivy, and other plants. These plants can combine to form a robust ground-cover that can withstand periodic mowing and some foot traffic. Mowing in such shade lawns needs to be carried out less often, since the plants grow more slowly due to the lack of sunlight. Care should be taken to not mow the lawn too close to the ground, as shady yards tend to have less dense growth, and removal of too many plants can lead to soil loss. In the most shaded yards, many people choose to forgo mowed lawns entirely and choose instead to use a ground cover that does not require mowing.