Lawn care after the flood

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If the recent deluge of rain means your luscious, closely-cropped carpet of green is now nothing but a soggy bog, you might be feeling a bit downhearted.

But don’t despair, say the experts, there is still hope for your languishing lawn.

Guy Jenkins, Johnsons lawn seed expert, firstly advises to just give it time.

“Don’t rush to work on your lawn as soon as the water has subsided,” he says. “Treading on wet, saturated soil will easily result in compaction, reducing your lawn’s aeration and drainage even further. Only sow seed after the ground has become workable again.”

Sometimes though, the only real option is to start again; if your lawn suffers from consistent waterlogging, or is covered in moss or has bare, muddy patches. Jenkins says sorting out a proper drainage system and sowing trusted grass seed will save you time and money later. On a poorly drained site where water lies on the surface at times, land drains are the only solution. If in doubt, seek professional advice.

When water simply won’t drain away, the RHS advises that you may have to replace the lawn with a new one, using turf laid on a 5cm (2in) bed of sharp sand, overlaid with topsoil improved by generous manuring and thorough cultivation.

Smaller lawns on heavy clay soil can frequently be drained by raising them slightly above the adjoining ground level. A gravel edging to the lawn will carry away excess moisture.

When a lawn lies wet for any length of time, damp conditions encourage algae, lichens and liverworts. This includes bubble-like Nostoc algae and dog lichen. They both flourish in badly-drained lawns but can develop wherever the aeration is poor and may even appear on well-drained turf if the surface has become compacted and is inclined to remain damp after rain.

Algae also thrives in shaded conditions and where soil fertility is poor, so it’s frequently found on turf beneath trees. Moss is a common sight where conditions are damp, but particularly if there is shade and an acid soil.

Pricking or slitting the surface can improve a waterlogged lawn, the RHS adds. Try making 2-3cm (1in) slits or holes, although deeper spiking is better, especially with a tool designed to leave holes 10-15cm (4-6in) deep. These holes can be filled with a free-draining material, such as proprietary lawn top dressings or horticultural sand, which will allow the water to flow from the surface to deeper, less compacted layers.

Hand spiking tools are available but an ordinary garden fork can be used too. Alternatively, for larger lawns, use powered tools. Try a hollow tiner, which has hollow spikes and removes plugs of soil that are then swept up and removed. Pricking and slitting are best carried out once the excess water has drained away, especially where machinery is to be used. In small areas where standing water persists, sweep it off the lawn and into the beds before spiking with a hand spiking tool or garden fork.

Once you’ve cleared the latest mess, it is also important to consider the root of the problem and hopefexampleully prevent it happening again. For exmaple, do you live in an urban area, at the bottom of a valley or flood plain, or on top of heavy clay?

“All of these factors can affect how your lawn copes with excess rainfall,” says Jenkins. “In urban areas, water flows over pavements and patios, with the extra surface run-off resulting in flooding.

“Simply by keeping a well-maintained lawn, providing somewhere for water to drain away, we can all do our bit to prevent flood damage.”

If you plan to sow a new lawn this spring, raking soil over to form a fairly fine tilth should ensure optimum germination rates, but only do it when the soil is dry enough to work.

Heavy rain washes nutrients out of the soil, so to help encourage new grass, apply a lawn fertiliser or buy grass seed which includes fertiliser or dressing, so that it can grow more extensive root systems better able to withstand drought and flooding.