Thatch is an essential part of a healthy lawn. Too much however can prevent sunlight and rain water from reaching new blades of grass, preventing them from growing healthy and green. This article provides all the information you need to know about thatch and how to tell when your lawn needs dethatching.
What is thatch
Thatch is naturally occurring in all lawns and occurs when leaves and grass stems of both living and dead grass intertwine and form a layer between the growing grass and the soil underneath.
What causes thatch
While thatch is naturally occurring, certain grasses and the way individuals manage their lawns affect how quickly thatch develops. Often excessive thatch growth is caused by poor lawn maintenance.
Common causes of excessive thatch build up include;
• Over fertilisation and watering. This increases the grasses growth making it grow faster than the grasses ability to break down thatch
• Cutting the grass too high
• Heavy clay soil
• Over use of pesticides and fungicides that kill or impede the growth of soil microbes and earthworms
When to dethatch your lawn
Generally every lawn should be dethatched at least once a year. The most common time to dethatch your lawn is normally around the end of March to the beginning of April. It is essential that before you dethatch your lawn that the weather conditions promote rapid and healthy grass growth after dethatching. This requires the weather to be warm and the lawn to be watered after thatch removable. It is also common practice to dethatch your lawn at the end of the grass growing season around the end of September.
How to tell if your lawn needs dethatching
There are three ways to tell if your lawn needs dethatching.
1. By touch. If you lawn is extremely bouncy underfoot then you are likely to have a thick layer of thatch on your lawn.
2. By sight. You should be able to see the soil between the grass blades. If you can’t and you cannot poke your finger through the grass to see the soil you are likely to have a thick layer of thatch.
3. Measurement. A simple way to tell the level of thatch on your lawn is to dig up a small section of the lawn using a trowel about 3 inches thick. Look at the turf sample and look for the layer of thatch that is sitting on top of the grass / soil. If it’s 1.5cm or greater it is time to dethatch your lawn.
What to do after dethatching
Dethatching can leave your lawn looking like a mess. Don't panic – it won’t last for long. Collect up all the debris and thatch and add this to your compost bin. Thatch makes a great natural fertiliser. When you have tidied up your garden, lay a thin layer of compost over your lawn and give it a good watering. This will help promote strong grass growth. In areas that are looking particularly bare March is a good time to lay some grass seed so that it grows in time of the summer.