Turf Tips: The importance of soil under turf
Preparation is so vital to the health and visual presentation of a new lawn. While people often think about top dressing lawn and top soil, the soil under turf is often overlooked despite its importance to the success of your preparation. This weeks turf tip dishes the dirt on why dirt is so important and how to do it right.
Quality matters
New builds are especially notorious for having new turf laid on the existing ground with no added soil under turf. Crusher dust, road base and other similar materials that often surround new builds offer absolutely zero organic matter to feed your new lawn. Existing poor soil especially clay based soil can also create problems and hinder your new lawn. To understand what your existing soil is like it is always good to start with a soil test. Unless you have perfect turf that is well aerated we suggest removing 100 – 150mm of existing soil to allow room for new quality soil under your new turf.
Quality turf undersoil combines free draining material such as sandy loam to allow for water to move through the material, with organic matter which retains water along with food for your lawn. It is also the perfect material for your new lawn to sink its roots down into unlike a heavy clay soil. By removing a layer of poor soil and importing quality soil you give your new lawn the perfect platform to thrive. Our sales team can help you with your soil, arranging for your soil to be delivered prior to your turf to allow time to prepare. This can all be on one convenient invoice.
Getting the right depth
As we said above, it is best to remove a layer of existing soil to allow space for new quality soil with the perfect characteristics for your lawn. The depth of new soil you bring in is important on two levels. Firstly, you want to allow for a decent layer of quality nutrients and organic matter found in a quality underturf soil. Secondly, you want to create a good base, that is free draining enough to allow excess water to flow through but also substantial enough to store a layer of water and nutrients close at hand.
We recommend bringing in at least 100mm of new soil for under your turf. For a depth of 100mm, you will need 1 cubic metre of soil for every 10m² of turf. This gives your new lawn a solid bed of organic matter that is free draining and full of nutrients. Using less than 100mm of restricts the amount of food your lawn can find and can inhibit water uptake. Air in another important factor, with old soil often compacted and lacking in oxygen. A generous layer of fresh soil under turf also gives more oxygen allowing your lawn to breathe better.
Levels
Not just an old Avicii song, great levels are vital for a great lawn. The grade of your lawn to allow for drainage so water can drain away and not pool is a very important step. While our turf farm uses GPS driven laser levelling to get the perfect grade you can use more of an eye test to create a gentle grade. You want the grade to be enough to help drainage, but not enough to create new problems with maintenance tasks like mowing.
With the grade of your new lawn now perfect for drainage the final and most important step visually is getting a nice smooth surface for your lawn. Any lumps and bumps, or worse divots or large footprints in your soil under turf will lead to those same holes, lumps and bumps appearing in your new lawn. Aside from not looking great, these can also cause problems with scalping your lawn when mowing or just making the task of mowing more difficult.
You should always get your soil under turf as smooth and level as possible when laying, this will give you your best-finished product. You can then use topdressing soil after your lawn is established to level off any small indents such as from where the Australia Post bike put tyre marks on your new lawn.
To get more advice on soil under turf or to order a new lawn and some soil call our team on (07) 3114 8230. You can also to pop in and order in person at our sales office on 1/243 Bradman Street, Acacia Ridge. The office opens Monday to Friday 7am to 5pm and Saturday 7am to 12pm.
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