Top-dressing is the process of adding specific materials, such as loam, sand and organic matter, to the lawn surface. This has a number of benefits but is mainly used to get the soil into its best growing conditions, to treat irregularities and improve the texture of difficult soils.
Like everything else with lawn care this has to be done correctly to be effective and there is a specific procedure you should follow.
Why We Top-Dress
The main reasons why we top-dress are:
- It helps to deal with thatch. Because the topdressing covers the thatch it helps the grass become denser and re-root and also dilutes the thatch layer, which help with the natural breakdown of thatch
- It improves the soil, with the addition of essential nutrients and helps build root structure
- It improves drainage. If your lawn is susceptible to waterlogging then adding a sand based topdressing with help firm up the surface.
- It helps build resistance to drought, if you apply a peat based topdressing
- It helps with overseeding
- It will help maintain and level the lawn surface. If you have any little hollows or undulations across the lawn then the topdressing can fill these in.
- It can improve the fertility of the lawn. With the addition of certain materials and nutrients, the topdressing can promote the production of healthier grass sprouts.
Just be careful when picking the type of topdressings you’re going to use. It has to be compatible with the existing soil as it will eventually become part of the root zone. Adding a topdressing which doesn’t blend with the soil will have next to no benefit and could make your problems even worse.
When to Top-Dress
Top-dressing can really be done at any point during the growing season but traditionally people will do it either in late spring or early autumn. You also want to do it in conjunction with other lawn maintenance tasks, so if you plan to aerate or scarify the lawn then do so before topdressing.
Even though they aren’t necessary, they could actually be very useful. Aerating gives access for the nutrients with the topdressing to reach the lower grounds of soil, right down to the bottom of the roots, and the scarifying clears the lawn of thatch so there’s less of a barrier covering the lawn surface.
How to Top-Dress Properly
Choosing the materials
To choose the correct materials for your lawn, you are going to need to know the type of soil you have. Of course the different materials will have different properties and nutrients so applying ones which your lawn isn’t in need of will just be a waste of time.
You should also build the mix according to the soils composition and health.
Types of lawn and their ideal mixtures:
- Sand Based Lawn. This type is likely to be free draining and prone to drought during the summer so go for a mixture that’s 4 parts loam, 3 parts peat and 1 part sand.
- Clay Based Lawn. This type is quite the opposite of the above as it would suffer from drainage problems, i.e. waterlogging, so you’re to need something that’ll firm it up. A suitable mixture for this would be 2 parts loam, 1 part peat and 4 parts sand.
- Loam Based Lawn. This soil is in-between the two above so it won’t suffer from their problems. But that doesn’t mean you can’t apply a topdressing, go for a mixture that includes 3 parts loam, 1 part peat and 3 parts sand.
As well as aerating and scarifying before you apply the topdressing, I would mow the lawn on the short side. This allows the dressing to penetrate the existing soil without causing any damage to the grass.
In order to carry out topdressing properly, make sure you follow this process:
- Cut your lawn quite short and apply a dry dressing to a dry lawn on a dry day
- Grab your dressing and portion it into piles evenly around the lawn so that there’s a pile per every few metres of grass.
- Now spread the piles into the areas of lawn they have been allocated to. You can either use a spade to scoop up and fling it or you can use the back of a rake and push and pull it into position.
- Now you need to brush the dressing into the soil, this has to be done a little more vigorously than above so make sure you use a stiff rake. This may be a slow process but this time and care will reward you with a much smoother lawn surface.
- The top dressing should be no more than a couple of cm deep so that about 75% of the grass blade is still left showing.
- Now give the lawn a few days to rest before you mow again otherwise the blades on the mower could get blunt from the contact with the material still left on the grass.
One other thing, if you do plan on scarifying the lawn or have any bare patches then should include an overseed into the operation. You can do this one of two ways: before or after.
If you have loads of dressing to work into your lawn then I suggest you seed afterwards, this way the seed won’t move around.
But if you have only a little layer to work in then you can add the seed first, this also protects it a little from birds and rain.
When top dressing a lawn, it’s normal to underestimate just how much you’ll need to cover the lawn and get the correct depth.
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