4 tips for Selecting Eco-friendly Soil for Houseplants
Hello gardeners!
Having recently received several houseplants, all in varying states of despair, my usual next step would be to repot the plants to freshen up the soil and apply fertilizer to give them a jump start back to health. Except now I look at gardening, including indoor gardening, through a sustainable gardening lens.
Do I want to buy a plastic bag of sterilized potting soil?
If I do not want to buy a growing medium, or what I normally call soil, packaged in plastic, where do I get soil suitable for indoor plants?
First, one quick definition. Soil. Soil is what plants grow in. Dirt. Dirt is what you sweep up off the floor. Home gardeners rarely would refer to soil as a growing medium, which is a horticultural grower's term. Experienced gardeners always use the word soil, and never dirt.
Why do we promote healthy organic soil outdoors, and indoors we use a sterilized medium with minimal organic matter sold in plastic bags? Of course no one wants to invite insects indoors. Is there a better option for soil for houseplants?
What can I use to feed my plants if I do not use a commercial synthetic fertilizer?
I have in the past relied on fertilizers for indoor houseplants. Primarily because I thought potting soil lacked sufficient nutrients. What is an eco-friendly fertilizer for houseplants? At this point I have not found the science to answer these questions for myself. In the meantime, I am using the following guidelines. Stay tuned to future blogs and I will share new information when I get it.
Prioritize soil that is eco-friendly, renewable and safe for your indoor houseplants.
The following are recommended options:
Avoid peat moss as an ingredient in the growing medium.
The use of peat moss in potting soils is not sustainable because of the environmental damage caused by its extraction and the loss of carbon sequestration by harvesting peat bogs. Peat is created in water-logged, oxygen deprived conditions where plant material such as sphagnum moss decomposes over 1,000s of years. Although it is natural, it is considered non-renewable because of the time it takes to create.
I have read that coconut coir, a byproduct of coconut processing, is renewable and capable of retaining water in the soil. Although once these products are shipped out of coconut growing areas, the footprint of this product expands. It is popular because it is inexpensive however I am not convinced this is an ideal soil additive for all geographical regions.
Use locally sourced ingredients.
As mentioned above in reference to coconut coir, sourcing materials locally reduces the carbon footprint of transportation. Check for potting soil blends made near you.
Consider incorporating an organic matter.
Traditional compost is not suitable for indoor use. Is it possible to find a locally made compost where the heat generated in the process is adequate to kill off undesirable odors and prevent pests? I would like to talk to a soil scientist to understand if this is even a possibility for indoor use. Stay tuned for future blog posts.
As an alternative to compost, an organic matter like worm casings may be an option. I have not personally tried worm casings for indoor plant use, but I am considering using it as a top dressing to replace the liquid soluble synthetic fertilizers I have used in the past.
Research indicates the worm casings are odorless and rich in nutrients, important for supporting thriving houseplants indoors. The essential nutrients in worm casings include nitrogen, phosphorus, potassium and other trace minerals, all in a form readily available for uptake by the plant. Apparently, there are also compounds in the worm casings that deters aphids and spider mites. Interesting. I definitely will have to ask an expert to confirm this.
Always opt for organic and certified products.
Look for potting soils labelled as organic or certified by a recognized organic licensing organization. It would be fantastic if these were sold in recyclable packaging or bring your own bucket scenarios.
The path toward a sustainable gardening practice is paved with small steps in the right direction. We can begin by asking the question, “Is there a better way to do this? Healthier for me and healthier for the earth.”
I am going to try worm casings on some of these houseplants I have inherited. I will report back on how I like it and what I have learned.
In the meantime let's get our hands dirty, and remember progress not perfection when it comes to sustainable gardening.