How I Enhance Fungal Ecology in My Garden

Healthy fungal populations mean healthy soil—and happier plants.

Ramariopsis kunzei is an edible species of coral fungi in the Clavariaceae family. It is commonly known as white coral mushroom. Armstrong Redwoods State Natural Reserve.
Ramariopsis kunzei is an edible species of coral fungi in the Clavariaceae family. It is commonly known as white coral mushroom. Gerald Corsi / Getty Images

One of the things I have been thinking about recently is fungi in my garden. Soil care is hugely important in any organic garden, but few gardeners really take the time to think about the amazing world of fungi that play such an important role in the soil ecosystem. 

The Importance of Fungi in a Garden

Without fungi, we would not be able to garden as we do. So many of the processes on which we depend as organic gardeners cannot function without a healthy population of different fungi. The strands of fungal hyphae (filaments) spread throughout the soil, working between soil particles and solubilizing nutrients to make them available for uptake by plant roots. The unbroken chains of fungal growth spread through the rhizosphere, binding the soil together and transporting water and nutrients to where they are required. 

Specialist fungi called mycorrhizae work by forming symbiotic relationships with plants—effectively increasing the surface area of their root mass. There are also plenty of other specialist fungi, which invoke immune responses in plants and thereby harden them to disease and attack, and perform other beneficial functions. But mycorrhizae are the group of fungi that I've been thinking about most.

Enhancing Fungal Ecology With Mycorrhizae

One of my current goals in my forest garden is to protect existing fungal populations and to increase the population of beneficial mycorrhizae. These are, of course, already present in the soil. Most soils and plants in healthy gardens have vast quantities of these fungi. I want to make sure they are healthy and strong; but to ensure that, I won't be buying in any mycorrhizal blends. 

Gardeners planting new fruit trees are often advised to add mycorrhizae to the planting hole. This is sometimes a good idea; however, mixes of mycorrhizae may not be the right types for your location and your plants. There are many different types of these fungi which interact and form associations with different plants. Choosing the wrong ones could do more harm than good. 

Protecting Fungal Populations

Generally speaking, it is better to improve the soil conditions, rather than looking for a "quick fix" and adding mycorrhizal fungi. While commercial mixes can be beneficial in a few very specific scenarios, in most cases there are better options.

Following "no dig" gardening practices, mulching with organic matter, using layered and diverse planting, and protecting the soil through minimal intervention can all help to create a rich and dynamic soil environment where fungi, plants, and other beneficial soil-life can thrive. This strategy is what underpins my efforts to improve the fungal ecology in my forest garden. 

mushrooms sprouting in cedar mulch
Mushrooms grow in cedar mulch.

Dawn Guy/Getty Images

Fungal Compost and Fungal Mulches

Where grasses, annual grains, and vegetables are being grown, the fungal-bacterial ratio is usually around 0:3 to 1:1. But orchard trees and other woodland or forest plants thrive in a soil with 10:1 to 50:1 ratios. Since the orchard where I am evolving my forest garden was previously a well-maintained lawn area with a few fruit trees, one key strategy has involved ensuring a fungal-dominant soil ecosystem. 

Creating fungal composts and fungal mulches with plenty of woody material and woodland biomass is helping me to protect and improve the soil so that mycorrhizae can thrive. In a closed-loop system, the small forest garden generates many of the materials, as does another area of more natural woodland on my property. 

Since I have seen fruiting fungi for the first time this year on wood chip paths through the forest garden, I believe that my strategies so far may be working—though, of course, the fungi we really want are mostly invisible to the naked eye.

I've been leaving more woody material around to decompose in place, trying to create a more evolved ecosystem with diverse habitats. Recently, I have been experimenting with reducing the nitrogen content and increasing the carbon content in my cold composting area in the forest garden, to find the sweet spot for a thriving fungal compost, as opposed to a bacteria-dominated aerobic composting system. I have been using ramial hardwood chips (ramial refers to chips from small- to medium-sized branches), as well as chipped softwoods from the property to provide the optimal conditions. I have also left the compost unturned to allow the mycelia to spread through the mix and so far have seen positive results.

I plan to use this new and improved fungal compost around my new forest garden plantings later this year. In addition to chopping and dropping, using this fungal compost will form a part of my forest garden fertility program moving forwards.