DETHATCHING YOUR LAWN, HOW TO KNOW WHEN TO DO IT, HOW TO DO IT AND WHAT TO DO AFTER ITS BEEN DONE. (SOMETIMES CALLED SCARIFY)

Only certain lawns need dethatching, but over their life time all lawns will need it done occasionally. Knowing when your lawn does need to be dethatched and how to dethatch it effectively is the key to a health and beautiful lawn. Dethatching will restore your lawns health and keep it beautiful in the future

WHAT IS THATCH IN THE LAWN?

Have you seen a cross-section of soil and grass roots, you can see a layer of organic debris known as thatch. It’s a comprised of a mixture of dead and living plant material, thatch forms at the base of grass plants, where the stems meet roots and soil. Some organic matter, such as small grass clippings or mulched up leaves, break down quickly in healthy lawns, but other materials take much longer to decompose. When the build-up of this material is faster than is decomposition the thatch layer of your lawn grows thicker.

A thin thatch layer, less approximately 1 centimetre thick (half an inch) is beneficial to a healthy lawn. It acts as a barrier formed out of organic mulch which help can conserve soil moisture and protect against fluctuations in soil temperatures. A thin thatch layer allows water, nutrients and air to penetrate into soil and reach waiting plant roots. But when thatch grows thick the grass suffers and the lawn becomes less vibrant.

Thatch layers of 2 centimetres (one inch) or greater act as barriers and are not beneficial to the lawn. A thick thatch blocks water, light and fertilizer. The grass roots get trapped in thatch, where they're vulnerable to frost, heat, drought and stress. Water from rain and irrigation can accumulate in the thatch layer drowning the grass roots making them suffocate from lack of air. An over thick thatch is a breeding ground for lawn disease and insect pests.

HOW TO CHECK IF YOUR LAWN NEEDS TO BE DETHATCHED

Check your lawn's thatch layer early in the spring season. Its important not to walk the lawn too much in times of frost as this can damage your lawn, so you will want to wait until the late winter early spring frost has passed or at least until the lawns have thawed.

To check the thatch use a small hand garden trowel or spade and dig up a small patch of your lawn grass and soil. You should clearly see and be able to measure its thatch layer. If your thatch is 2 centimetres (1 inch) or more, can probably already see signs of poor grass colour and weak, thin growth. If you can confirmed your thatch exceeds the healthy depth it is time to dethatching your lawn.

The best time to dethatch is in spring when the grass growth is accelerating and your lawn will recover quickly from the effects of dethatching.

The dethatching process will make the lawn look very unsightly for a few weeks but after dethatching the grass growth will accelerate and the lawn will look better than ever.

Never dethatch when your lawn is dormant or stressed, you may damage it beyond recovery.

Lawn aeration and dethatching are two different processes, but they can work together to help your lawn. Aeration removes cores of soil, including their thatch layer, and creates paths for water and nutrient to penetrate thatch and compacted soil. This helps prepare thatch for removal and speeds the breakdown of existing thatch. Dethatching helps slice through thatch into soil and remove the barrier of thick, accumulated organic matter.

HOW TO DETHATCH YOUR LAWN

If your thatch is over 2 inches thick, you may want to consider hiring a dethatcher (Scarifier) from a hire centre for the task. This will have a rotating spring or blade head which will cut that thatch and rake it out to thin it. Vertical mowers/verticutters have vertical blades that slice down through the thatch layer into soil. They pull the thatch and grass roots the surface as they go. Verti-cutters are best for thick thatch layers on lawns in need of extensive renovation. The Blade depths can be adjusted to control how much thatch you remove at once.

https://mower.ie/product/scarifier-hire-in-kilkenny

Alternatively there is a very popular item that can be easily fitted to nearly every make and model of lawnmower. This is a universal dethatcher blade.

https://lawnmowerpartsonline.ie/product/16-dethatcher-blade

The 16 inch is most popular as this job is hard on lawnmower engines and the smaller blade is easier to rotate on all model lawnmowers. Its not necessary for the blade to cover the entire deck width of the lawnmower for it to be effective.

For much larger lawns there are very popular tow behind dethatchers. The most popular are made by Agrifab and are available in

40 inch widths

https://lawnmowerpartsonline.ie/product/agri-fab-40-towed-tine-dethatcher-45-02941

And 48 Inch widths.

https://lawnmowerpartsonline.ie/product/agri-fab-48-dethatcher-45-02951

Manual dethatching rakes from brands such as Wolf Garten are also very popular.

https://lawnmowerpartsonline.ie/brands/wolf-garten

But this option is very slow and laborious.

Whatever option you choose, finish the job by raking up all the thatch debris and watering your dethatched lawn thoroughly.

WHAT TO DO AFTER DETHATCHING

With dethatching done, it is time to re-seed and feed your lawn. There are many products on the market which are ideal for this. Put on the recommended amount. Not too much fertiliser should be applied until the lawn has ahd a little time to recover as if the weeks are dryer this may burn the lawn and slow it redevelopment.

Check your thatch depth again every couple of years and follow soil test recommendations to keep soil pH and nutrients at optimal levels for thick, healthy grass growth. Sometimes a lawn may need lime to restore its PH balance, this is also beneficial for the control of thatch-reducing microorganisms.