Topsoil and potting soil may appear similar at first, but the truth is that they have almost nothing in common. Both of these have specific uses and if you want your plants to thrive, you have to choose the right type of soil for their needs. Choosing between topsoil and potting soil will depend on a number of key factors such as your location, the types of plants you intend to grow, and the amount of volume needed for planting.

In this article, we’ll be discussing the differences between topsoil and potting soil to help you select the correct soil type for your plants.

What is topsoil?

As the name suggests, topsoil is simply the topmost layer of soil that’s scraped from weedy fields or other natural spaces. It can be rich river silt, have sand and clay mixed in it, and have weed seeds present as well. When you buy topsoil, you’re not exactly sure what you’re getting unless you go to the landscraper’s supply yard and ask about their soil. You can do a quick soil test to identify the nutrients that need to be added to make it suitable for garden applications.

Where is topsoil used?

While topsoil may vary according to the soil supplier, they do provide a solid base for a raised bed, container, or garden. Most gardeners improve the topsoil by adding in compost and well-decomposed manure prior to laying them on top of fill or poor soils. Whatever you do, do not mix in gravel, clay, or sand as these will harden topsoil and turn it into a concrete-like mass when it dries up.

Some of the most common applications of topsoil are:

  • Soil Topper – In many areas where the soil is extremely poor or when contractors scrape it away for, topsoil is used to create an environment where landscape plants can grow. To achieve the best results, gardeners usually till the top of the existing fill or soil, rake 5-8 cm of topsoil over it, and then till again. Mixing a bit topsoil with the fill provides a transitional mix that allows the plant roots to penetrate the fill.
  • Raised Gardens  If you’re looking to establish a raised garden, using topsoil is an ideal choice. Most gardeners mix topsoil with compost and peat moss to create a mix that’s perfect for gardening. Depending on the topsoil’s quality, the mix might be somewhere around 3 parts topsoil to 1 part compost. When creating a mix for a vegetable garden consider adding in along with equal parts topsoil and peat moss.If the topsoil is acidic, make sure to wear, goggles, gloves, and a dust mast before mixing in lime for the soil test. If the topsoil comes out alkaline, you can increase its acidity by adding in peat moss and sulphur. If the topsoil is filled with clay or sand, add additional compost or cor bark to promote better drainage and water retention.
  • Container Gardens – While potting soil is the ideal choice for container gardens, topsoil can be used in soil-based mixes. A basic soil-based mix includes equal parts topsoil, compost, and sand, perlite, or vermiculite. Although this mix is heavier than commercially available potting soils, it does provide good drainage for potted shrubs, trees, and other plants.

What is potting soil? 

Potting soils are a type of soil that’s premixed for container gardening. The ingredients in potting soil are usually made of peat moss, perlite, and compost, but may vary across manufacturers and intended applications of the mix. Some potting soils also contain fertilizers and wetting agents that work well with specific plant types. It’s best to read the instructions on the package to ensure you’re getting the right kind of potting soil for your plants.

Types of potting soil

Potting soil comes in many different varieties to suit different plant types. Some of the most common types of potting soil available are:

  • All-Purpose Potting Soil An all-purpose mix is mostly used for one season of growing flowers or vegetables in container beds. To produce a good harvest and encourage flowering, consider using a water-soluble fertiliser.
  • Seed-Starting Mix Seed-starting mix is a lightweight, quick-draining, sterile potting mix intended to start seeds. It contains additional perlite or vermiculite, so tiny, delicate roots can extend into the mix. It may contain a starter fertilizer.
  • Cactus and Succulent Mix Succulents and cacti, such as the Opuntia species, require more drainage than regular potting soil. Potting soil mixes for cacti are usually made of compost, peat, and perlite or vermiculite with a little bit of horticultural sand added.
  • Orchid Mix – Orchids need a well-aerated mix that doesn’t break down quickly which is exactly what this type of potting soil is.. Most mixes have that chunky consistency that resembles the natural environment. Orchid mixes may include peat moss, coconut husks, charcoal, perlite, and/or vermiculite.