It has been quite some time since I last added fresh soil to my garden. I recently took advantage of some fall sales and went to get bagged garden soil that was just a little over $3 per cubic foot. However, upon inspection, the bags didn’t seem to have the right weight for a cubic foot of soil. This led me to explore other options and look at soil selections, scrutinizing the ingredient list in an attempt to justify the price tag.
Choosing the soil mix
For some reason, I never had the curiosity to check the ingredients of the bagged soil. This time around, inflation and the appearance of new brand names intrigued me to find out what difference they offer.
To start the investigation, I had to decide on which kind of mix to look into. Since I have a raised bed, I went with raised bed mixes.
There were about five brands in my store to choose from, including the common Miraculous brand.
I also took a look at two expensive brands that are only available online in my area.
Checking the ingredient list
There are three elements to look for in the label of bagged soil:
- Bulk ingredients
- Fertilizer
- NPK ratio
Bulk ingredients
As I was reading the first part of the list, it seemed like a copycat sentence on all the bags.
They all had aged forest products, sphagnum peat, dolomite lime, and fertilizer. Then the list is followed by specified ingredients for certain states, mainly California, Texas, Idaho, Oregon, and Georgia.
The most expensive one had the least number of ingredients, listing aged forest products, perlite, peat moss, and fertilizer.
It’s worth noticing the percentage of this bulk material. Each brand had a different amount of it. They all varied between %50 and %90.
In conclusion, if the list states two or three elements, such as decomposed forest material, peat moss, and compost, the product is not good enough for growing anything. It could be used as a filler amended with richer soil.
Sand and perlite are important elements for better drainage, and the other organic components add more nutrition.
The addition of microbes is a bonus, but they can be found in wood chips and organic fertilizers.
Organic fertilizer derivatives
Again they all seemed to have the same ingredients with a difference in one or two.
Poultry manure, feather meal, kelp meal, and worm castings were the common sources of organic fertilizer.
The Miracle had a bit more on its list, adding alfalfa and bone meal.
Fox Farm had oyster shells, mycorrhizae fungi, and humic acids as additional ingredients that none of the other brands had. Does that mean their price is justified, I am not so sure.
NPK values
As we all know Nitrogen (N), phosphorous (P), and potassium (K) are the essential macronutrients every plant needs to thrive.
These elements are typically found in fertilizers and soil amendments, and their ratios are important for different stages of plant growth and specific plant needs.
A fertilizer with an NPK ratio of 10-10-10 would contain 10% nitrogen, 10% phosphorus, and 10% potassium. Usually, this is referred to as an All-Purpose Fertilizer.
- Nitrogen (N): Important for leafy green growth. It is a major component of chlorophyll and is essential for photosynthesis.
- Phosphorus (P): Vital for root development, fruit and flower production, and overall plant growth. It also plays a role in energy transfer within the plant.
- Potassium (K): Contributes to overall plant health and helps in the synthesis of proteins and carbohydrates. It also aids in disease resistance and stress tolerance.
Organic fertilizers usually come in numbers less than %10 ratio and are granular slow-release. The most common liquid organic fertilizers are either fish emulsions or liquid seaweed.
Some companies, like Espoma, have come with other liquid concoctions that contain humic acids and beneficial bacteria.
Looking back at the soil collection, the most common ratio was 0.3-0.1-0.1 with a few adding the Calcium as a fourth element.
How to choose the right soil
After the above explanation, there are a few factors to consider when choosing your bagged soil.
- The price: the price range varies from one state to the other. In central Texas, the lowest cost is $3.33 per cubic foot for basic garden soil. Most other mixes are at about $5 per cubic foot.
- Garden needs:
- For a new garden, I suggest filling the raised bed with the cheapest garden soil and other affordable elements, then topping it with richer soil. You can also add good soil to only the planting spot.
- Amending an existing garden depends on its soil needs. If you notice good growth but no production, go with the soil that has less Nitrogen. If your garden seems tired overall, top it with a layer of the richer soil that you can afford.
- Diversity of fertilizer sources, especially those that are not easy to get. Some examples: are kelp meal, alfalfa meal, bat guano, and mycorrhizae.
