The Dirt on Dirt

 by Kate Wilson

We all know that when we put a shovel to the ground here in central Ohio, it can be a bit of a daunting task. We have dense, heavy clay soil which can make digging a hole tiresome, and doesn’t exactly promote healthy plant growth.  At Oakland Nursery, we always recommend amending your soil when planting. With what exactly?  Anything! Anything that contains organic matter will help break up the density of the clay. Any version of topsoil, compost, or peat will be better than choosing to not amend your soil at all.

In many newer housing developments builders backfill around houses with subsoil. Our soil is typically broken up into multiple layers or horizons. Topsoil, the upper most layer, usually containing leaves and organic matter that’s beginning to breakdown (humus). The next layer in central Ohio is going to be dense clay soil (NE Ohio also has clay soil, but with a more acidic pH. Which is why a certain number of plants thrive better than in our clay alkaline soils – think rhododendrons, azaleas and hydrangeas with blue flowers!) But I digress: it is imperative that you amend your soil.

So what is the best amendment? I’ve always considered Topsoil to be the “all purpose” bag – works in most situations and is budget friendly. I’ve reserved my use of costlier compost for perennials and veggies. I’ve used peat when I’ve put down grass seed, because it’s the cheapest and a lot of it is needed for seed.

Having said all that, I recently did some more research the matter. Research as in: I bothered to read the ingredients on the bag. All the bags. I’m going to share my results with you – with pictures!


I couldn’t believe my eyes- no mysterious, un-pronounceable ingredients. Whether topsoil, compost, peat and even potting soil, the main ingredient – the one that takes up 90% of the bag or more – is peat! Reed Sedge Peat to be exact. Do hear what I’m telling you?! The scoop is that these soils are all peat based.

Topsoil (Garden Magic brand) is peat with a bit of sand mixed in. And even though there’s just a small percentage of sand, that sand has value. The sand serves to make the composition lighter and helps with drainage. Something that breaks up our dense clay and promotes healthy plant growth.

Compost: peat with manure. There are few options offered when it comes to compost. Holy Cow has a higher compost to peat ratio blend than the Oakland Garden Magic, and is priced accordingly. Posey Power is another popular option because it contains horse manure, rather than cow manure. It should be noted that horse manure is considered, um…”hot” due to its high nitrogen content compared to cow manure. It’s great for leafy greens, garlic, potatoes or corn- but cow manure would be the preferred choice when using it for flowering veggies (tomatoes and peppers) or perennials.

Peat: 100% peat – no bones there.

Now, this isn’t ground breaking or negative – I just never realized. Did you know that these products were all peat based?

The initial lesson remains the same: amend your soil. Add this peat (with sand, manure, or whatever) because it will help build your soil profile. Some blends contain more soil nutrients than others. Any amendment is better than no amendment.

….But wait….what about Potting Soil?

Potting soil is, like topsoils and composts, peat based. The main difference with potting soils is that it contains perlite. Even though there is only a small percentage of perlite, it is important, like sand with topsoil or manure with compost. Perlite will keep air spaces in your soil, preventing it from getting compacted in your container- and compaction means less air and water getting to the roots of your plants..

There are so many options (7 is my current estimate) when it comes to potting soil. Promix, Mircale-Gro, Fox Farm and Garden Magic are just the different brands. There are more options then within each brand, a different mixture for any use. Promix has two blends, both containing mycorrhiza, which is a fungus that helps with root absorption. Mircale-Gro also has two blends, which contain different mixtures of fertilizer tailored to their intended use. While Fox Farm potting soil blends contain earth worm castings and bat guano. And Garden Magic is the most budget friendly, containing only peat, sand and perlite.

Are there noticeable differences in plant growth using one or the other?….If only I was in middle school again…this is a great science fair project just waiting to be done!

In the meantime, that’s the dirt on dirt. 🙂

Happy Gardening!


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