Topsoil is one of our most important natural resources. It takes approximately 500 years for one inch of topsoil to be created by nature. Topsoil is generally the first 6 to 12 inches of looser soil that you will find in your yard and garden. It is becoming a scarce commodity due to conventional gardening and large scale landscaping.
Topsoil is becoming eroded in many places due to poor gardening practices. Many large agricultural operations have not learned the lesson from the dust bowl which was caused by growing the same crop in the same place year after year. Using this method of farming quickly robs the soil of the nutrients that it needs, and makes it more difficult for plants to grow in that soil. This means that the topsoil does not hold together well and quickly washes away, or is carried away by the wind.
Importance of Quality Topsoil
Quality topsoil is important, and means that your soil has the proper balance of nutrients and the right consistency. It is easier to amend the soil to include more nutrients than it is to try to adjust the consistency. The best way to find out where your topsoil is in terms of quality is to test the soil’s pH, or even better to take a soil sample for testing at your local extension office. Topsoil should fall into the pH range from 5.5 to 7.0 and can be tested with a simple pH meter. If you want to know more, have the test done. They will tell you the chemical make-up of the soil and what may need to be added for a productive garden.
Use Caution if Buying Topsoil
There are no regulations regarding topsoil that is sold to you. You should always be cautious and find out about the soil before you make a purchase. Sometimes, topsoil you may buy could be worse than the topsoil you already have. This is one of those times where you may think that you have found a bargain, but in this case, cheaper is probably not better.
Make sure to check with others before using a supplier. It is good to get a recommendation from local nurseries or other gardeners before buying topsoil. They are likely to know who the good suppliers are. Soil should be free from debris like large stones, tree roots or other trash. Most suppliers will screen soil to remove this at a slightly higher fee. You can choose to buy the soil unscreened to save money, but realize that there will be a lot of work involved.
Some soils may have been taken from old farm land, and you should be aware that there can be residues of herbicides, pesticides and chemical fertilizers in the soil. If you want to avoid this, find out where the soil has come from, or ask to take a small sample to have tested.
How and When to Amend Topsoil
Once you have the soil tested, you will have a better picture of what you are dealing with. When you do, you will know what amendments you need. You can amend topsoil in a number of ways. These include adding compost, manure or peat moss as well as adding nutrients such as nitrogen, potassium or phosphorus. This is done by digging the amendments into the soil and allowing them to incorporate for a period of time.
Soil amendments are best added a few months before you sow your seeds, or soon after your garden is done producing for the year. Caution should be taken when amending the soil with manure as fresh manure needs months to break down before it is safe for your plants. You can age manure prior to incorporating to be sure that this will not be a problem. A great time for soil amendments is in the fall when they will have time to break down over the winter. Then your soil will be ready to get started in the spring.
Want to learn more about quality topsoil?
Check out these excellent resources from extension agencies:
Testing Topsoil Before Purchasing from Oregon State University Extension Service
Buying Topsoil from the University of New Hampshire Cooperative Extension