By Laurence Gale MSc
With such a mild winter, moss growth in most parts of the UK has been prevalent. Many Groundsmen will be keen to eradicate it as quickly as possible. Many people use the widely tried and tested method of applying Lawn Sand with the aim of burning the moss out and then scarifying / brushing out the dead moss debris.
"Lawn Sand" is a mix of one part sulphate of iron, three parts sulphate of ammonia and twenty parts dry sand. It is applied at the rate of 140 grams per square metre. The sand material acts as a carrier for the active ingredients (iron & ammonia). It is important when using these materials to ensure that they are spread evenly over the turf surface. The best method of spreading lawn sand is by using a spreader.
It is important to calibrate the spreader in advance to see what spreading rate it gives when operated. Simply fill the spreader with some dry sand and operate it over a measured hard standing (tarmac, concrete, paved) area. This enables the sand to be swept up so it can weighed afterwards.
Once you have the weight of the material spread over a given area you can calculate how much has been spread over a square meter. Using this information you can work out how much material your spreader is spreading. Most spreaders have a sliding aperture which can be adjusted to give a set desired application rate. Once the amount spread has been calculated over the given area, adjust the aperture accordingly.
You should also note the spreading width of the spreader when operated at a walking pace. If the spread is five feet (two and a half feet either side, then that will be your working width. Do not overlap when turning. You could lay down string lines at five feet intervals to ensure you do not overlap. but most people tend to use their mowing bands as a guide.
Windy conditions can also affect the spreading rate. ideally you need to apply Lawn Sand on a dry day with little or no wind.
Over dosing or applying Lawn Sand in the wrong conditions (when soil is too dry) will cause the sward to burn / scorch. It is vitally important to ensure you apply as per manufactures recommendations and during the right weather conditions.
It should be safe to walk on the turf after it has been watered or received sufficient rainfall to wash the material into the soil. It is important to water the turf within the first 48 hours of any applications if there hasn't been sufficient rain.
Lawn Sand works because the powdered active ingredients (iron and ammonia) clings to the moss and broad leaves of the weeds. Thus burning and severely scorching their plant leaf tissues.
The treated areas will begin to show results quite quickly. However, the speed of 'die-back' will be dependent on weather conditions and how active the moss is. The moss will begin to die back usually between 1-4 days after application.
Additionally Lawn Sand also provides a tonic for your lawn and has a definite 'greening' effect. It is normally applied in late spring but where moss is a problem it can also be re-applied during the summer.
Visit the Pitchcare Shop to buy Lawn Sand.