Three Myths You Shouldn't Believe About Topsoil

by Jenny Banks

Topsoil is a fertile soil that can be used to improve gardens or lawns, but there are a lot of myths circulating about this product. Here are three myths that you should not believe about topsoil.

Topsoil can't contain weed seeds

You may have heard that topsoil can't contain weed seeds, but this is just a myth. To understand why this is the case, you need to understand how topsoil is made. Generally, topsoil comes from excavation sites like new subdivisions. The builders remove the top layer of soil that contains the grass, plants and weeds, and then they collect the layer underneath, which is used to make topsoil. Since the soil comes from a deeper layer of the dirt, it is 95% weed free, but it's not impossible for weeds to be present.

To make sure that weeds don't sprout from your new topsoil, treat it with a pre-emergent herbicide after you spread it on your lawn or garden. These herbicides deactivate any weed seeds that are present so that they aren't able to germinate. If your topsoil does introduce some weeds into your new lawn, contact a professional who specializes in lawn weed control for assistance.

Topsoil makes fertilizer unnecessary

Since topsoil is a rich soil, you may think that using it makes fertilizer unnecessary. If you purchased your topsoil by the truckload, it won't have added fertilizer, and will be low in nutrients. Topsoil that comes in bags is pre-fertilized, but the nutrients added to the topsoil may not be the nutrients that your lawn or garden needs.

You'll need to test your existing soil to find out which nutrients are lacking, and then have the topsoil tested as well to find out which nutrients it adds. The results of these tests will let you know if you need fertilizer or not. If the topsoil contains all the nutrients that your soil is lacking, you won't need fertilizer.

Topsoil shouldn't be mixed with your existing soil

You may think that topsoil is supposed to be spread on top of your existing soil, not mixed with it. If you do this, you may introduce drainage problems to your garden. This is because water moves through each type of soil at a different rate, so if the topsoil is to spread on top of your existing soil, water may pull between the two types of soil and damage your plants.

Instead, mix your topsoil with your existing soil, and aim for a 1:1 ratio. Mixing two soils in this way improves the quality of your existing soil without introducing drainage problems.