A Guide to Better Grass Cutting

In order to cut grass effectively a basic understanding of grass agronomics is useful.

Grass grows when soil Temperatures are above 6-8 Degrees Centigrade. Grass needs, moisture, nutrients, Carbon dioxide and sunlight.

At the base of the grass we have the crown, stems (culm) grow up to nodes. The leaf forms from here in different directions.

Grass is phototropic and the leaf grows towards the light, the leaves tend to taper so more light can reach more of the leaf to enable effective photosynthesis (converting light energy into chemical energy in sugar bonds using chlorophyll, causing the essential green in grass).

The Grass also needs a healthy root structure and a soil with an Acidity (pH) level at around 6.5.

Grass is most productive when it under goes a defoliation process (Grazing or Mowing).

Maximising leaf growth and thus photosynthesis. When it loses a proportion of leaf it has retained excessive nutrients for the size of foliage and therefore grows quicker and healthier.

The Basis of an average healthy lawn is to maintain grass at between 2" and 3". Cut the grass on a regular basis and never more than 30% of the standing length. Cut the grass when it needs it, disregard calendar based schedules; the growth will vary with temperature and moisture.

When we drop the cutting height down to ½" to ¾" we then come away from Grass areas to Lawns.

More care has to be taken being conscious not to cut too short during the summer drought period. Little moisture is retained in the soil, the lawn will scorch and then turn brown, once moisture returns the grass will recover. Do not cut too close during winter periods as this can create areas of sparse growth and moss will form in the weak or shaded areas. Avoid too much traffic on the lawn during hard ground frosts.

Your lawn will require periodic aeration. This will create better drainage and ensure surface water drains effectively, it also breaks up compaction in the soil promoting healthy root growth. Sacarification removes thatch (a layer of dead grass, culm and moss), letting light through to more of the leaf and ensuring more of the leaf remains green decreasing yellow patches on the lawn after mowing.

Fertilising needs to be carried out very carefully ensuring you have an understanding of your lawn acidity level, monitor the weather either side of fertilising. The principle minerals to promote a healthy lawn are Nitrogen, Phosphorous, Potassium and Iron. DO NOT OVER FERTILISE, this can cause burning of the grass. Take advice from the fertiliser supplier.

Mower Choice.

A general purpose mower would be rotary. It consists of a Horizontally rotating blade with sharpened blade tips, there are also fluted turn ups to create an air flow suction to help the grass stand vertically prior to being cut and facilitate collection.

The action of cutting with a rotary blade damages the grass it is therefore important that blades are sharp!

Rotary mowers are available with collection systems.

Although cutting in the wet is not advisable it often happens, it is therefore crucial to ensure that the vortex shape of the deck, the engine speed, mower throat are of a good design, to ensure good collection performance. To facilitate good collection performance it is paramount that the Grass box is clean to ensure air can escape from the box, if air cannot vent through the mesh or cloth on the box it will not collect.

Ensure that your engine is running at maximum speed.

Rotary mowers can be bought either as a 4 wheel machine or rear roller. 4 wheel machines generally do not cut as low and are better suited for rougher areas, whilst the roller machine gives a tighter cut and

Defined strip. The rear roller mower is also useful to enable an improved cut on lawn edges, a 4 wheel machine will drop both wheels of the edge and scalp, the Roller mower does not.

Four wheel machines are also available as mulchers. This type of mowing is proving more and more popular. It is successful providing strict rules are adhered to. Try and cut grass when dry and NEVER exceed 1/3rd of the standing length of grass at any one mow. If you see cut grass lying on top of the lawn, stop, lift the height of cut and continue. Small changes in cut height will make a dramatic difference to the overall effect.

If you follow the above guidelines mulching is very successful: No trips to the tip to dispose of clippings (good for landfill sites). No piles of rotting grass which unless mixed and turned with other organic matter is useless as compost anyway.

Added moisture and nutrients going back into the soil will enhance the grass and save on costs of fertiliser. Frequent mowing reduces the amount of weed in the Lawn. The above principles of the Rotary mower will also apply to ride on mowers in general but other factors have to addressed such as scalping and manoeuvrability.

The Cylinder mower will provide a far higher quality of cut, due to the shearing action of the blades (similar to cut from a pair of scissors).

It relies less on the speed of the blade therefore is quieter and consumes less power, consequently less fuel. The grass is cut rather than thrashed, it is not bruised and damaged in the same way therefore is less prone to yellowing and disease.

The cylinder mower needs more maintenance; the cutting cylinder to blade clearance needs to be maintained. Adjusted correctly the cylinder and blade will remain sharp for a considerable length of time. Neglect this and the blades will dull quickly causing damage to the grass and a very poor quality of cut. The cost of sharpening the cylinder mower is considerable in comparison. Traditionally the cylinder is removed spun ground in a special grinder, the bottom blade is resurfaced, and the machine is reassembled and set. There are exceptions to this In-Situ grinding in which the cylinder remains in the machine this reduces cost but means bearings and seals cannot be checked cleaned and lubricated.

Relief grinding is another variation, which is growing in popularity (driven mainly by the manufactures).

This is a process where each blade of the cylinder has a relief edge ground on to it, giving a more honed and perhaps sharper blade this enables the blade and cylinder to have a clearance between them.

Reducing wear, reducing power absorption and an improved quality of cut.

These principles apply to pedestrian machines, self-propelled and Gang units.

Grass cutting on slopes “the basics”


Understanding the main causes of accidents on slopes

1. Machines traversing a slope in excess of its safe working angle, causing it tip over.

2. Machines tipping over backwards caused by over loading and or driving up a slope to steep. Implement carried too high on three-point linkage

3. Traction breakaway most common descending a slope. Forward speed will increase faster than the rotation of the wheels causing a “tobogganing effect” and complete loss of control. Caused by too steep a slope poor condition of tyres too heavy a load.

4. Lifting units whilst on a slope with Self-propelled cylinder mowers and Bat wing mowers.

· Be able to evaluate safe working angles and machine suitability

· Know the limitations and manufactures safe working angles for your machine If it exceeds it don’t use it!

· Understand the effects on stability and traction with various changes in ground long wet grass, short grass with grass clipping on the surface. soft, hard or friable and loose surfaces, dips and rabbit holes etc.

· Carry out a risk assessment for each specific job.

· Ensure the machine is maintained as per manufacture specification. Tyres in good condition with correct pressures.

· Ride on machines fitted with ROPS should have lap belts. Do not use restraining belts without ROPS being fitted.

· Be aware when ROPS are fitted the stability of the machine is reduced. Check with manufactures specification.

· Whilst traversing a slope at the end of each run always turn with the heaviest part e.g. mower deck facing uphill.

· Ensure 4WD is engaged (if fitted) before you access the slope.

· Understand the use of differential locks when they are appropriate to use · Be very aware of the changes in the Cof G when lifting and lowering units on self-propelled cylinder mowers and Bat wing mowers. These machines are very unstable with units lifted. On no account should you lift and lower units while on the slope, lower units on the flat and then drive on the slope.

· Operate the machine as if on Ice, no sudden speed or direction changes.

· Remember stay within the manufactures safe working angles for the machine, if you don’t know find out from the machine manufactures and fit a Tiltmaster inclinometer to find out the angle of the slope.