When you hear landscapers or farmers talk about loam and topsoil, you begin to wonder if the two are two separate things. After all, farmers talk about having good, loam-y soil for planting, so you might assume that they are the same. However, that is not entirely the case. Here is some more information on loam and topsoil to help clarify how these soils are related and different.
Topsoil is a very rich, dark, soft earth that has a lot of nutrients in it and has more decomposed organic material in it than loam. The terms are often confused because both are used to plant flower, fruit and vegetable gardens, depending on the needs of the plants or trees. You want the topsoil for the nutrients it provides and the loam for the water control. Both can also be placed into the holes dug for planting, and both can be used as the surface soil around the bases of plants and trees. Both have valuable planting information on their bags, which you will need to consult prior to purchasing either of these kinds of soil. However, that is where their similarities end.
Loam has an entirely different texture, smell and coloration than topsoil. In fact, it may be sandier, siltier or comprised of more thick, heavy clay. It looks and feels more like something taken from a riverbed, a beach and the ground remnants of a potter's wheel. It helps retain moisture for plants that require more moisture to grow, and prevents the rapid loss of nutrients into the surrounding soil by keeping the nutrients close to the roots. Some landscapers even use "clay" pots made of loam to surround topsoil and plants before placing these biodegradable pots in the ground.
Loam is also any combination of sand, silt and clay, which means you need to read the labels on bags of loam to find out what combinations of these three ingredients exist in the bag. This is very different from topsoil, which may only list the PH level and not really list the contents. For example, most acceptable loams for planting in the U.S. comprise a 40/40/20 sand, silt and clay mixture, and that will be listed right on the bag. There are several other combinations and formulas for loam that are crafted in a soil processing factory, so you need to read the label and buy only what the care labels on your plants suggest.