Pitches are covered to keep the pitch and bowler take off areas dry. Keeping the pitch dry is essential for good, safe ball bounce, and for player traction and stability.
This is because the clay soils used in cricket pitches lose their strength when wet. Clay soils are also very slow drying so once a pitch is wet – it can take a long time to dry out, delaying play.
The type of cover you use will depend on what is available but it will either be a single flat sheet or mobile covers.
The two types of cover affect moisture in the pitch in different ways. Any cover will reduce the rate of drying of a pitch, compared to being left open to the sun and air.
Flat Sheets
A flat sheet cover will prevent the pitch from drying out by limiting air movement and acting as a barrier to evapotranspiration (although some flat sheets are breathable and can allow a little surface moisture to evaporate, even when covered).
The grass will become stressed if the cover has to be in place for 3 days or more due to reduced light levels.
Flat sheets also tend to create a moist surface and therefore the grass may be more prone to disease. Since flat sheets reduce the rate at which a pitch dries out, or stop drying completely, they allow the moisture deeper down in the soil to spread to the surface; this is sometimes described as ‘pulling moisture to the surface’ (or ‘sweating up’). Whilst that means you do need to allow a bit of time for the surface to dry off after the cover is removed, you can use this to your advantage if the surface is drying too quickly and you need to slow this down, or if you wish to soften the surface enough to allow a pitch to be re-surfaced with the roller.
To prevent a pitch from becoming too moist at the surface, a coconut (coir) or hessian matt may be placed on top of the pitch under the sheet to absorb excess moisture.
The challenge with all flat sheets is that if it rains, the water on the sheet either needs to be mopped up from the surface before the cover is removed, or tipped into a freely draining area. A water removal roller with a sponge and collector (whether push-along or powered) can speed this process.
Water running off sheets may concentrate into low points and run back under, so in heavy or prolonged rain, the sheet needs to either be large enough to ensure that any run-back stays well away from the sensitive areas or that surface levels are advantageous.
Be very careful when deploying even a narrow sheet in windy conditions because they are still large enough to lift 2-3 grown adults off their feet and to cause arm-shoulder and other injuries.
Tips on flat sheets:
- If you are using a flat sheet cover on a pitch, you can make it easier and safer to handle by rolling it up on a tube and then rolling it out when you need to deploy. This is especially useful in windy conditions since the sheet is always kept flat to the ground and so there is less chance of the wind getting underneath it. You can use a section of twin-walled solid drain pipe to do this – the larger the diameter the easier it is to roll up/out but the heavier and more bulky the storage. Specialist inflatable rollers are the quickest method, and are often used for very large sheets.
- Moving a sheet is a manual handling task and should be approached as such, however, moving a sheet in windy conditions should have its own risk assessment, since any sheet can act as a sail. – If in doubt, do not get it out! Getting the game on is important but it is not worth causing serious injury – whether it be to the people putting the sheet out, or the people who will have the sheet flying towards them if it blows out of the control of the grounds team/players deploying it.
- Make sure there are a suitable amount of people to safely handle the sheet (this will mean more people when it is windy)
- Plan the task and make sure that everyone knows the plan, as well as what to do if a gust of wind gets hold of the sheet.
- In windy conditions always keep the leading edge of the sheet taught and low to the ground.
- Never, ever wrap a handle around your hand or wrist! You must always be able to let go if necessary.
- Always peg the windward side of the sheet first, otherwise it can end up on top of you.
- If the wind is gusting and the sheet becomes unmanageable, do not all hold on. This just turns the sheet into a large sail. Depending on the wind strength, if everyone but one person lets go, the sheet will quickly blow downwind and will take the energy out of it. Do not get dragged along by it – let go and shout warnings to anyone downwind. However you should not be getting into this situation – if in doubt, do not cover.
- Rolling out is the best way to deploy any sheet in windy conditions. The weight of the rolled sheet is more condensed and you can peg as you go and the sheet stays close to the ground.
- Make sure players are not walking across the sheet with spikes on - this creates holes that leak.
Mobile Covers
Mobile covers are raised above the surface so do allow some air movement and drying. They may still be used to slow down the drying of a pitch, since they provide shade, but the pitch will still continue to dry, even if it is raining.
They do not stress the grass as much as flat sheets when they are in place over a number of days because some air flow can be maintained.
Furthermore the water falling on the cover can be channelled away.
Because the covers are normally made up of three to four separate units that join together when in position, they do need more people to put in place quickly compared to a single flat sheet – but with the right number of people, deployment times are around the same as a flat sheet on a pitch. The removal/recovery time is quicker however, because the water is already dispersed from the cover so they can be removed straight after the rain stops.
Mobile covers are a more expensive option for pitch covering, as compared to a single flat sheet with push-a-long water remover but they are more effective at keeping a pitch dry because there is no risk of run-back, the pitch still continues to dry even when they are left in place, and they may be left in situ for longer without worrying about the health of the grass. You may be able to offset some of the costs by selling sponsor logos printed on the sides of the covers by the supplier. They also need to be stored when not in place which can cause maintenance and storage issues.
Mobile covers are at risk of movement in high winds so securing covers with ballast, stakes or tie-downs can help but there will be a wind speed at which the movement cannot be controlled and a flat sheet rolled out, or no cover at all may be the only safe options.
The type of covering you choose for your club needs to work for your club, your budget and how you operate.
Covering to Control Pitch Drying
Covers can be really helpful in managing moisture content in pitch preparation – in both wet and dry conditions. For more information, see the guide on Pitch Preparation Click here
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