Elder Creek said no to organic fertilizers back in 2010.
Actually, we say no to all fertilizers wherever possible and use organics for only a very small window of need.
Of course, our choice for fertilizer will always be organics vs. synthetics, but organics should still be a last resort, not an easy crutch to compensate for poor choices regarding soil health.
Elder Creek was a design, build, and maintain landscape firm at that time. We used our maintenance division to develop new and sustainable landscape management methods.
It was then that we began to question our practice of periodic fertilizer applications in all of our landscapes. We were already using organics. We started there, but we were concerned about the embodied energy and ecological impact the harvesting of these materials was having and wondered if it was really necessary given all the work we had done to develop healthy soils.
So, we spent three years testing this over 40 accounts.
We found that the majority of our plants did not need fertilizer additives to thrive and experienced no noticeable decline of vigor from repeated mulch applications once a healthy soil structure and biome was established. Some heavy feeders, such as rhododendrons and roses, did remain on fertilizer schedules.
What's wrong with Organics?
While some organic fertilizers are upcycled byproducts of poultry and other livestock operations, some are linked to very destructive mining processes or, at the very least, carry unnecessary environmental impacts such as increased carbon emissions, impacted water quality due to runoff, poor soil conditions due to improper applications, mining of wildlands, and promotion of excessive crop production for the use in the fertilizer. It simply not as clean of a solution as we tend to think it is.
What's the answer?
As with most softscape-related issues, we can solve this by focusing on soil health.
This does NOT mean importing potting soils.
Lava rock, peat moss, perlite, and the like are linked to devasting mining practices. The environmental degradation and carbon impacts of these products far outweigh their value in the landscape.
It's as wasteful and foolish as grinding down a brand-new Tesla to make aluminum cans and plastic dog toys and claiming it's "eco" because we "recycled" it.
What this does mean is enhancing your native soils.
Start by testing and properly applying organic matter and biology. In some cases, nutrients and minerals must be supplemented, but that should be done after testing and on a case-by-case basis.
Incorporating compost and a biological inoculum is a key practice to enhancing the soil you have, eliminating the need for excessive soil imports, and getting off fertilizers.
Healthy soils consist not only of the physical and nutrient properties but also of the biological life within it. (Photo: mycorrhizal extending from a root)
Make a habit of adding biological soil life to all of your projects through freeze-dried inoculum, aerated compost teas, or both!
When all of these components are balanced and functioning, water can be physically held in the soil, and fungi can move water, sugars, and minerals throughout the system to where they are needed most.
Mulch
Most professionals mulch their landscapes, but few realize how many ecosystem services it is actually providing or how critical it really is.
Protecting the top of the soil from wind, heat, and the impacts of rain is another critical component in soil health. Woodchip mulch is the most common and effective landscape strategy for this needed protection. A gallon of diesel fuel can easily produce 10 yards or more of mulch. So it has a reasonable carbon footprint for the time being.
What about nitrogen tie-up?
The same voices pushing for soil imports tend to be the same voices concerned about woodchip mulch robbing the soil of available nitrogen.
I would agree if we were growing carrots, but we're not.
Perennial plants from commercial nurseries tend to arrive so well-fertilized that we have ample nutrients to sustain them through any short-term nitrogen deficiency that may occur.
Note I said, may occur. I have yet to see a study or any field evidence showing this is a real-world concern.
Mulch is playing important roles in all aspects of the 3 pillars. It assists in building and protecting healthy soil systems, which are the critical foundation of all plant and water-based aspects of our professions.
Once we see the true cost of our manufactured soils, fertilizers, and additives, we can no longer claim professional responsibility without minimizing/eliminating their use. We can't have it both ways. Professionals lead.
Rick Taylor
Principal, Elder Creek Design Studios
More information on carbon in the landscape can be found on the Sandbox website.