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Repairing a flood damaged lawn

31 March 2014 by Rolawn

Repairing a flood damaged lawnHaving just endured a wet and thoroughly miserable winter, the recent arrival of what definitely feels like spring will have most people chomping at the bit to get out in the garden. Unfortunately your much loved outdoor space is likely to have taken a hit this winter, with no fewer than five records broken over the past few months for what many experts believe has been unprecedented rainfall. Depending on where you live, the consequences of over half a metre of rain between early December 2013 and late February 2014 can range from a slightly soggy lawn to some serious flood damage.

If the state of your postdiluvian lawn has reduced you to despair and you are already thinking about extending the drive, laying a super large patio or digging a koi pond, take a deep breath and have another look out there. The situation might not be as irreparable as you fear. With a little time and not necessarily a lot of money most lawns can be rescued. Some patience and following sound advice will soon have your lawn back to its former glory.

It’s best to keep off the lawn until it’s visually dried out and doesn’t look like it requires wellies to venture onto it. How quick this process will be depends on the soil underneath. Lawns that benefit from a sandy, light soil usually drain well and once the water level has dropped, tend to recover quickly. If you have a heavy clay soil then you will find the water hangs around longer. Once the surface water has subsided you can get on there with a rake and remove any leaves, debris and dead matter so you can take a closer look to assess the damage. Are there thin or even bare areas? Are there areas where moss or weeds have invaded? Does the lawn need major overseeding or minor dressing to recover or is it simpler to just replace it with new turf?

Turf is a relatively robust entity and, once the lawn is fairly dry, you can start the repair process. If you are finding surface water is taking a long time to drain away you can help by using the old technique much loved of premiership football pitch groundsmen, namely the garden fork driven into the lawn and wiggled around. Doing this every 150mm across the lawn will open up the soil and help the drainage. If your lawn has dried this technique is also useful to introduce air into the root zone, as your lawn is likely to have become compacted with the sheer weight of standing water. If you are not blessed with naturally quick draining soil, then brushing topdressing into the many holes you have just created will also boost the drainage quality of the soil for the future.

Now might seem a strange time to think about mowing the lawn but letting the grass get too long before you cut it will not help your lawn's appearance. A good mowing regime will make a big difference in stimulating grass growth during the spring, which in turn will aid recovery of the lawn. Your mower needs to be in tiptop condition and if you haven’t been able to maintain it over a wet winter, now is the time to ensure everything is sharp and oiled properly. Remember (as ever) not to remove more than one third of the grass height during one mowing session.

Lawns that have not significantly flooded this winter will still have experienced torrential rainfall which will have leached vital nutrients out of the soil. Consequently, most gardens will benefit this spring from some work and TLC to improve growing conditions; for lawns this means ensuring your grass has access to the correct 16 essential elements so it can grow and flourish. Now is a good time to apply a suitable spring lawn food such as Rolawn GroRight® Lawn Fertiliser, Weed & Moss Killer. With the degree of leaching which this winter's weather has created the lawn will benefit from a repeat application after four to six weeks.

Now the soil issues of drainage and nutrients have been addressed it is time to think about improving the actual grass and repairing damaged areas. Overseeding any lawn that is looking sparse will improve the appearance and reduce weed and moss invasion which are likely to have been the only things to really flourish this winter. However, you may also want to re-sow specific areas where plant loss has been particularly bad. Spring is a good time to do this and a quality seed such as Medallion Premium Lawn Seed can either be sown evenly across the whole lawn or on specific bare patches without treating the whole lawn. If you are filling in bare areas then sowing rates should be adopted as if you were sowing a brand new lawn (around 35g per square metre). Seed left sitting on the surface of soil will not grow well unless the soil has been prepared correctly to provide a nice seed bed. With an existing lawn a spring tined rake can be used to break up the soil surface; with specific patches the area should be broken up more thoroughly. For general overseeding the seed can be mixed into some topdressing, however, this may involve a little trial and error with the application rates. If it doesn’t rain (and chances are, when we all need it, it won’t) then don’t forget to water two or three days after sowing. Seed germination can be accelerated by heating the soil up before sowing and by covering the seed for the first few days. Both tasks can be done with something like a black bin bag, pegged over the area in question. Check the area daily and when new grass growth can be seen remove the black bag and allow the grass plants to develop naturally.

Try and avoid walking on the newly overseeded lawn for at least a week and up to 21 days if possible. If you need to protect the new seed from our feathered friends, netting or garden fleece can be used until the new shoots start to come through the soil.

For large patches of ‘drowned’ turf the simplest option may be to lay new cultivated turf. This will need the soil to be prepared correctly, especially to get the height of new turf to match up with the existing or remaining. But you get the obvious benefit of an instant transformation. New turf and existing turf will probably vary in colour and appearance initially, even if putting new Rolawn turf with existing Rolawn turf, which is due to the age of turf and the relative level of nutrients in your lawn and the turf supplied. With a good growing season and appropriate maintenance any variations will gradually blend together.

Hopefully these tips will help your lawn recover from the wettest winter in living memory and avoid that extra-large block paved area in your garden! Don’t forget a healthy lawn assists during heavy rainfall by being absorbent which reduces surface run-off, it also absorbs CO2, produces oxygen, traps dust and particulates, is self-cleaning, safe to play on, and during hot weather helps reduce urban warming by being up to 30 degrees cooler than tarmac and paved surfaces.