We heard about an article that’s been making rounds these last two weeks telling people they should never reuse the same planter soil twice, as it would be robbed of all nutrients. This article encourages people to replace their potting soil every year. This is not only incredibly wasteful, but it also seems there’s some misinformation here that we wanted to clear up.
Should I replace my planter soil?
Soil is often thought of as a disposable product. The thinking goes that when you buy it new, it’s fresh and full of nutrients. These nutrients become depleted over the course of the growing season as the plants feed on those nutrients. By the end of the season, the soil is considered “dead”, or no longer containing the nutrients and microorganisms that it contained when it was first bought, and it can/should be thrown out.
But this is a mistake. Soil is not disposable. If it were, nature would not utilize the same soil over and over again for centuries. Soil is simply a receptacle, an environment for nutrients and microorganisms, and it can be revived. You can restore all the necessary nutrients and microorganisms by applying natural fertilizers and probiotic treatments.
You can restore all the soil’s necessary nutrients by using fertilizers like kelp (which is high in nitrogen) and bone meal (which is high in phosphorous). These natural fertilizers also contain the many micronutrients like boron, sulphur, and iron that plants need to grow.
One popular way to restore microorganisms is through compost tea. Compost tea will inoculate your soil with whatever strains of microorganisms were contained in the composted material. If you like to DIY your own ferments, this can be a good way to revive your soil. Here at Toronto Horticulture, we prefer to use our Essential Plant Probiotic, a similar kind of fermented solution but formulated to contain the exact strains of microorganisms that plants prefer. We like having a more standardized potency of the microorganisms we’re promoting, and we see better results with our plants.
So can I use my planter soil forever?
We should mention here that soil does have a lifespan. Even with natural nutrient and probiotic treatments, soil physically breaks down over time. But this takes years. A sign that your soil is aged beyond recovery is when it is so thin it has actually turned to dust. Think desert sand, which is naturally poor in nutrients and microorganisms.
Also, soil should not be reused if it has suffered a pest or fungal contamination, or if it has been contaminated with toxic chemicals like gasoline. (Whereas the microbes contained in Essential Plant Probiotic have been shown to repair contaminated soil, this process takes years, which is longer than most people are willing to wait!)
We regularly treat all our soil with natural fertilizers and Essential Plant Probiotic, and we use the same soil (from healthy plants!) over and over with no loss of growing power. Case in point: this cute Sedum planter we created for our kitchen window! To suggest that soil needs to be replaced every year is both misinformed and wasteful.
So please hold off on throwing out all your soil until you have considered your other options! If you have any further questions about whether or not you should replace your planter soil, reach out to us using the Contact page!