Too often I hear folks say, “I shouldn’t be having problems, I added topsoil.” While it sure sounds good to have added topsoil, it is not always a good thing and it is almost always a crapshoot when it comes to knowing what quality you’re getting when you purchase topsoil. Let’s look a little more into this.
Buyer Beware
Topsoil is the uppermost layer of soil and is generally higher in organic material and soil organisms. The depth of topsoil can vary depending on a large number of factors, but it is true that most plants grow better with a good bit of it. Unfortunately, there is no regular standard for what topsoil is. Well, I say unfortunately, but in reality each type of soil is going to need its own standard for what is a good topsoil. This means that any topsoil sold in the U.S. can be just about anything. It is not even clear that what is sold needs to be real soil!
Adding Foreign Soils Sometimes Causes Problems
Not all soils are built the same way. The basic types of soil are sand, silt, and clay. Most soils are some combination of the three, but often tend to lean to having more or less of the three types. When one soil is placed onto another soil and the amounts of sand, silt, and clay are different it can literally stop water in the top layer of soil until a puddle forms. After the puddle is drained the water will stop moving again until another puddle forms on top. Roots are similarly restrained. And without a good source of water, roots don’t have much reason to be moving anyway.
Better to Improve What you Already Have
Basically it means that if you can work with the soil you have it will likely not cause you additional trouble. Rocks only cause problems for turf, root crops, and when you are planting. If you are planting shrubs or perennials, you will only have to worry about them once, and then you will bury them for good. If you are doing carrots, potatoes, or other root crops, a raised planter may be a better option. If you do choose to use any type of soil for it you will have less problems by making the added soil deep. I prefer at least 18 inches, Over the years it has proven to work well and has been largely problem free. Turfgrass and annual flowerbeds are going to be a more difficult problem. To grow a satisfactory lawn in a rocky soil may take a bit more doing and may really require bringing in some additional soil, and my usual fix of putting 18 inches of soil into a lawn may not be a practical option. In this case you need to become an expert in your own soil. But you can be sure that if the soil you add is more than just a little bit different than what you already have, you will have more problems than you started with. The same goes for the annual flowerbeds.
In the end it is usually more productive to improve the soil you already have by practicing no-till and heavy mulching. This may take longer, but the quality is unquestionable and you stand a much better chance of not ruining your lawn or flowerbeds permanently.
Manana!