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What means top dressing and its results
Characteristics : amendment to use for top dressing
Steps for top dressing

Which soil amendment to use for top dressing

The choice of amendment depends on the nature of the soil. Generally, in 75% of cases, pure compost is used.

In sandy terrain, the soil is unable to retain the nutrients and rain water. In this situation, it is recommended to use a mixture composed of 75% compost and 25% peat moss. The purpose of this mix is to enhance soil cohesion, water retention and other fertilizing elements.

On terrain containing high levels of clay, the soil is very compact which considerably reduces gas transfer. In this case, it is preferable to use a mixture composed of 50% of compost and 50% horticultural sand. The purpose of this mix is to separate clay particles furthering gas transfer and soil porosity.

Suggested characteristics of top dressing mixture
Since top dressing is a mechanical process, the moisture rate of the amendment used must be maintained at less than 60%, ideally between 40% and 50%.

The amendment must have a fine texture and a homogeneous structure. It must be well strained and free of large debris that will otherwise appear in the grass. Finally, the amendment must be free of weeds. To accomplish this, it is necessary to avoid mixes that contain black soil and more particularly domestic compost made from garden and/or kitchen waste, since domestic compost often contains undesirable grass seeds.

Required quantity of soil amendment
Required amendment volume to top dress 1 000 sq² or 93 m² according to desired thickness:

Thickness Required Amendment Volume
inch milimetre ft³ yg³
1/16 1,6 5,2 0,2 0,15
1/8 3,2 10,4 0,4 0,30
1/8 6,4 21,0 0,8 0,60
1/2 12,7 42,0 1,6 1,20

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