How to maintain your lawn if it has poor topsoil
Top dressing can help to retain moisture, but it's a slow process that takes patience
Q We are having some issues with our lawn. No matter how much water we pour on the lawn it always looks dry. The blades of the grass do not spring back when stepped on and it just looks bone dry most of the time.
My husband decided to investigate what was under the grass and found that the topsoil was very poor. There was probably no more than five centimetres of topsoil on top of a coarse sand. We think that the water just runs right through the soil and drains away. Is there anything that we can do to solve this problem other than tearing up the lawn and starting fresh? A The thin layer of top soil and sand is a surefire way of getting any water to drain away very quickly. You will need to build up the topsoil layer to help retain the moisture. Top dressing might be a solution but it is one that will take a few years to see some results.
Top dressing is simply adding soil to the top of the lawn. It should be done in small increments because adding too much soil at once can kill the grass. I would not add more than 2.5 cm of top dressing at a time.
The top dressing can be just topsoil or it could be compost or a combination of the two. I strongly recommend using pure compost or the combination rather than straight soil. The compost will help improve the organic content of the topsoil and this will help a great deal with adding the ability to retain more water.
You simply rake the top dressing into the grass. Make sure that you do not smother the grass. Top dressing is normally done in the summer or early fall when the grass is tall and actively growing but could also be done in late spring.
Adding this top dressing will, over time, build up the level of the existing top soil and should help your problem with the water draining away too quickly.
To increase the benefit of top dressing you could consider aerating the lawn before applying the top dressing. This will help to work the top dressing down more deeply as you rake it in.
By adding a few centimetres of top dressing each year you can get a nice thick layer of topsoil in a few years.
The bonus in using this method is that the lawn will benefit immediately from the nutrients in the soil/compost and this reduces the need for fertilizer applications.
Every week, Growing Things Outdoors runs online at edmontonjournal.com or, if you prefer an epaper format, epaper. edmontonjournal.com Learn more by emailing your questions to filipskigerald@gmail.com, reading past columns or my book Just Ask Jerry. You can also follow me on Twitter @justaskjerry01.