Why top dress a lawn
Lawn top dressing is the task of applying a layer of sand/soil/peat mix to a
lawn. It has many benefits to the health of the lawn and the reasons for top dressing include:
- Maintaining a true and level lawn surface - Top dressing fills in all of
the small hollows and undulations therefore creating a level lawn surface.
- Help prevent thatch build up - Regular top dressing helps dilute the
thatch layer and will also help with the natural breakdown of thatch.
- Improve the drainage - If your lawn suffers from water logging, by
incorporating a sand based top dressing it will improve the drainage and firm up the surface.
This is particularly effective after aeration has taken place and the top
dressing has been worked into the tine holes.
- Improve the drought resistance of the lawn - As above but substitute peat
- In certain cases can improve the fertility of a lawn - Top dressing may
contain nutrients which in turn will stimulate growth.
- Helps promote new grass growth - Top dressing stimulates the grass to
produce fresh shoots therefore increasing the sward density resulting in a healthier lawn.
- Improves the soil structure of the existing root zone.
- Improves the resilience of the lawn.
When is the best time to top dress a lawn
Lawns can be top dressed anytime of the year during periods of grass growth (April - October).
Traditionally this task has been carried out during late spring and early autumn
as part of the main spring renovation and autumn renovation programs.
However as previously mentioned it can be carried out at any time during the summer when
conditions are favourable
Materials used for lawn top dressing
The three most common materials used for top dressing are
- Sand - Choose a sand with a medium particle size, not too fine and not too
coarse. Sand should also be lime free which rules out sea sand.
- Peat - Use a quality sphagnum or sedge
peat that has been finely sieved.
- Loam - Go for a good quality finely graded loam that is
too neither sandy or too clayey.
How much of each to apply depends on the root zone of your lawn and what you want to
e.g: If your lawn had a very high sand content it may suffer from drought during dry periods,
therefore by adding a peat based top dressing it would help improve the drought
resistance. Alternatively using a sand based dressing would improve the
drainage on a wet lawn.
Mixing lawn top dressing materials
As previously mentioned sand, peat and loam are mixed together to create a lawn top
dressing. How much of each you use will depend on the soil type of your lawn, typical mixtures for
different lawns would look like this:
- Sand based lawn - This type of lawn would be very free draining and prone
to drought during hot & dry weather. So go for a mixture of 4 parts loam,
3 parts peat & 1 part sand.
- Clay based lawn - This type of lawn would be suffer from drainage problems
during wet periods. A mixture suitable for this lawn would consist of 2 parts
loam, 1 part peat & 4 parts sand.
- Loam based lawn - A loamy soil which is neither sandy or clayey, would not
suffer the extremes of the previous two types of lawn. A suitable mixture would contain
3 parts loam, 1 part peat & 3 parts
When mixing the lawn top dressing aim to mix enough for an application rate of 3 - 4Ib per
How to apply the lawn top dressing
Ideally top dressing is applied after some type of lawn renovation has taken place, e.g
aeration (particularly hollow tining) and or scarification and overseeding.
Choose a dry day and mow the lawn before applying the top dressing as this will help with
working/brushing the top dressing into the grass.
Spread the top dressing over the lawn as evenly as possible at a rate of 3-4lb per
sq/yd. Leaving it to dry before working it into to grass will help the dressing go down to
the base of the sward and will also help it fill and aeration holes.
The back of a landscaper rake or a 5ft plank of wood with a handle attached can be used to work
the top dressing into the lawn. Alternatively specialist equipment such as a drag mat or a true
lute can be used for this task. Do this task as many time as necessary to work the top dressing