As part of my research on soil products I became aware of the fact that most garden soil is not garden soil. If it is not soil what is it?
What Is Soil?
Soil does have a proper definition and in addition to air and water it is made up of sand, silt, clay and a small amount of organic matter (usually less than 5%). If I buy some “soil” I would expect it to contain these ingredients.
What Is Bagged Garden Soil?
I would expect it to be a good quality soil. An ideal amount of sand, silt and clay along with an above average amount of organic matter.
To see what is actually sold in my area (Ontario, Canada) I decided to visit a larger garden center, Canadian Tire, and check the ingredients in their products. To be fair to manufacturers, I have included every product they had and I have presented them in the order in which they were laid out at the store.
The stated “ingredients” are the ones listed on the package. The ‘apparent ingredient’ is my impression of the ingredients when I handled the contents (several brands had an open bag so you could see the product).
Sunshine Natural & Organic Flower & Vegetable Soil
Ingredients: Peat, processed bark and compost
NPK: n/a
Apparent Ingredients: n/a
Marketing Claim: A natural and organic mix that is specially formulated for organic gardening
Golfgreen Enriched Lawn Soil
Ingredients: Organic matter, sand, starter fertilizer
NPK: 0.02-0.03-0.02
Apparent Ingredients: n/a
Marketing Claim: for use with grass seed to thicken and repair lawns. Helps retain moisture for faster germination and establishment
Scotts Turf Builder Enriched Lawn Soil
Ingredients: n/a
NPK: 0.08-0.03-0.02
Apparent Ingredients: n/a
Marketing Claim: grows grass 33% quicker and 50% thicker than native soil.
Miracle-Gro Potting Mix
Ingredients: n/a
NPK: 0.21-0.11-0.16
Apparent Ingredients: peat, composted wood
Marketing Claim: Plants with more blooms and more color. Grows Plants Twice as Big.
Miracle-Gro Moisture Control Potting Mix
Ingredients: n/a
NPK: 0.18-0.1-0.1
Apparent Ingredients: peat moss, composted wood, slow release fertilizer, perlite
Marketing Claim: Absorbs 33% more water and feeds up to 6 months.
Miracle-Gro Organics Mix
Ingredients: peat, compost, poultry liter, forest products
NPK: 0.1-0.07-0.1
Apparent Ingredients: n/a
Marketing Claim: absorbs water and sends nutrients right to the roots, so plants grow up big and strong. Get more bounty – vegetables, herbs, fruits & flowers (vs unfed plants).
Golfgreen Organics
Ingredients: composted manure with peat
NPK: 0.5-0.5-0.5
Apparent Ingredients: peat moss
Marketing Claim: revitalizes and naturally increases nutrient levels in soil for plants
Garden Club Top/Garden Soil
Ingredients: n/a
NPK: n/a
Apparent Ingredients: soil, composted wood
Marketing Claim: a screened, prepared, compost-enriched soil. Makes excellent garden mulch.
Garden Club Black Earth
Ingredients: n/a
NPK: n/a
Apparent Ingredients: soil, composted wood
Marketing Claim: an outdoor garden soil which improves soil structure, drainage and aeration, and fertilizer retention.
Garden Club 3-in-1 Mix
Ingredients: n/a
NPK: n/a
Apparent Ingredients: soil, composted wood, peat moss
Marketing Claim: the soil booster you want for your flowers, vegetables and lawn.
Does Bagged Soil Contain Soil?
The national brands do not contain soil. Garden Club is a cheaper local brand and it seemed to contain soil, but the bags do not specify their ingredients. Even Garden Club soil is mostly organic material.
Bagged soil is mostly organic matter and may or may not contain any soil. None of the bags I looked at were soil!
A couple of the products are labeled as potting mix, which normally means it is a soilless mix. So the lack of real soil is not a surprise in such products.
Labels on Bagged Soil
I am surprised that most bagged soil does not have an ingredient list. It is a product that is not regulated so they don’t need to tell the consumer what they are getting, but still, not even a simple ingredient list?
This tells me that you have no idea what you are getting with some brands and that the contents probably change from time to time.
Don’t buy a product that does not have an ingredient list.
Marketing Claims
Most of the marketing claims are true because they apply to ALL soil and organic matter. Adding organic matter to soil improves the soil, grows better plants etc.
Here are my comments on a few specific claims.
“A screened, prepared, compost-enriched soil that makes excellent garden mulch.” – soil does NOT make a good mulch – how can soil be a good mulch for soil? In this case the product is mostly composted wood, so it would make a good mulch.
“Absorbs water and sends nutrients right to the roots” – this product is organic matter so it does absorb water. However, no bagged soil will “send” nutrients to roots. This is just a marketing person dreaming up good sounding words.
“Plants with more blooms and more color. Grows Plants Twice as Big.” . I am sure this kind of claim works well with average consumers, but not with the smart ones. “Grows plants twice as big” – twice as big as what??? Using no soil? Plants that are not watered? Using a competitive product? Without a comparison the statements mean nothing.
“Grows grass 33% quicker and 50% thicker than native soil” – at least this one has a comparison, native soil. The problem with the claim is that native soil could be extremely good soil that is very nutritious. It could grow grass quicker than the bagged stuff. This is just an unsupportable marketing claim.
Bottom Line
Bagged Soil is usually not soil.
If you need soil for your garden you should probably get a bulk delivery of real top soil.
There is a “community garden” here where “topsoil” gets delivered in bulk. Took a sample. The jar test is weird. Very little floats, but I see neither a clay layer nor a sand layer. The stuff on the bottom is black.
Lots of partly decomposed wood chips. Is the rest sawdust?
Had a lab do a basic soil test. Very high in P and K. Organic matter is 25% (don’t know whether this includes the larger wood chips or they were screened out by the lab.)
Germination test vs. known good soil in my flower pots shows great germination rate and normal seedlings (only about an inch high so far in both samples.) I used tomato seeds from store bought tomatoes.
Bottom line — it’s ok as a growing medium. Would expect it to settle as the wood gets decomposed. Would only trust it for ornamentals. PS I’m in the US (Maryland, mid-atlantic region)
Most of the woods particles that are found in bagged soil are from sewer treatment plants . They take the sludge human poop and other thing that go down the sewer system. Mix it with a carbon source( wood chips) bring to high temperature composting it . Large amounts of this end up in your bagged soil or on farm field.
This would be great could be great with the exception that our sewer system are full of chemicals. The bpa’s micro plastics and so on . Also a larger portion of our population is on some form of drug some of these drugs do and some don’t break down in the composting process. The bio solids have been used in the United States starting in the 70 . A few farms have been shut down by the government due to the levels of forever chemicals found in the water . I believe it was a farm in Maine, Michigan and Omri compost facility in Massachusetts. On a small back yard garden with all of the raised beds being filled with soil from outside sources. My belief is that the levels could actually be even more harmful.
Do you have any proof that is true? What country are you talking about?
“If you need soil for your garden you should probably get a bulk delivery of real top soil.” I would if I could. Topsoil is often at a premium on Vancouver Island so what is sold by landscaping supply companies is usually just a combination of sand, compost or fish compost, etc. I don’t think clay is ever a component of bagged or bulk products.