I’ve been noticing for the past few years that the quality of commercial potting soils has gone way down. This is the case with every brand I have tired, including Home Depot’s Vigoro, Lowes’ Sta-Green, Walmart’s Expert Gardener and Kellogg Garden Organics. The problem with these potting soils (especially Kellogg) is that they are composed of a large amount of non-composted wood chips. As a result, these wood chips rob much-needed nitrogen from the plants “grown” in these potting mixes and my plants always suffer as a result.
All these companies, when I confronted them via email, told me that these wood chips are all decomposed enough to not rob any nitrogen from my plants, but I know from a few years of using these soils that this is a bunch of BS. It’s very clear just by looking at these wood chips that they are much too fresh to be considered even slightly decomposed and the lack of growth (or even outright death) of my plants prove that there simply is not enough nitrogen available to them.
It’s very clear that these companies are saving money at the expense of their customers’ plants by mixing and bagging their soil too early thereby creating more space for the next batch. Space is expensive, I get it. But you can’t package this stuff and sell it as potting mix. It’s not, it’s junk that’s no good for your plants!
In the case of Kellogg, it was so bad that I had to replace all my potting soil completely three years ago. Once I did, I was able to save my nitrogen-needing plants and everything was fine. At that time, I had actually bought a decent amount of the Kellogg potting soil and I had a good amount left. Not knowing what to do with it, I just left in bagged-up it under my picnic table. The next year I opened the bags to see what it was like, and I found a nice, black, seemingly-rich and fertile potting soil. So I used it on a few contains and, lo and behold, my plants did thrive.
You see, what happened was that these wood chips all decomposed as they sat in the soil mix in the bags on top of my picnic table, creating a nice, composted, rich potting soil! This is when it hit me. The solution to good commercial potting mix is to not buy it and use, rather to buy it, store it for a year outside in it’s bag, then use it the following year!
So ever since, I have been buying all my potting soil a year in advance . So, for instance, this year, all the potting soil I used is from potting soil I bought last year and all the potting soil I bought this year will be used the following year, so that it has time to compost for about a year and become good, nutrient-rich soil for my potted veggie plants!
So if you have the same problem that I’m having, try it. Buy some potting soil this year, store it outside where it is exposed to the elements (sun, rain, snow, everything) and you’ll find that next year it’s the best potting soil you’ve ever used! (No thanks to the companies, of course.)
What about Miracle-Gro?
Personally, for veggies, I stay away from Miracle-Gro potting soil. Not only is it too expensive, but it has a very low amount of nutritious organic matter in it (which is why they load it up with Miracle-Gro fertilizer). All I see in Miracle-Gro potting mix is a HUGE amount of peat moss, some perlite and a very little amount of these tiny, thin twigs. It’s great for flowers, but not such a great medium for veggie plants. Nothing beats composted organic matter and a potting soil with that much peat moss simply does not compost that well using my method above. It just becomes a bag of wet, mushy peat moss. But to be honest, even if Mirace-Gro potting mix had a higher rate of organic matter in it, I would never buy it due to it’s high price (even on sale) – I believe in gardening on the cheap!
I know what some of you are thinking, BUT PEAT MOSS IS ORGANIC MATTER. Yes, but it simply does not compost well when it is the only organic matter present. It just sticks around doing nothing but getting wet, drying up, getting wet, drying up, etc. It’s great as a water retention medium, but that’s about it. Too much of it and not much of any other organic matter is OK for annual flowers (or perhaps a seed-starting mix) but not for veggie plants.
Bonus Tip (for Container Flowers)
Now I must admit, these other brands aren’t that great for potted flowers. There is too much dense matter in these potting mixes and drainage is very poor. This is where Miracle-Gro has an advantage. So to correct this problem, I buy a huge bag of the cheapest perlite I can find and mix more perlite into my composted potting soil. (My ratio is about 2 parts composted potting soil to 1 part perlite – this ratio does not have to be exact, it’s just a guideline.) This makes the composted potting soil much lighter and fluffier with better drainage, which most annual potted flowers need.