In the world of soil science, nature’s gardens are classified into 3 layers: the ‘L’ litter layer, (aka detritus, litterfall or duff) is the top, undecayed layer of dead plant material (my mulch), such as leaves, bark, needles as well as animal poop, skin and carcasses, feathers and whatever else happens to land on the surface; the ‘F’ layer, the partially decomposed organic matter (my compost) and the ‘H’ layer, which is the fully decomposed organic matter, (aka stabilized dark soil, humus, or basically – nothing much left to eat).
The litter layer is broken down or decomposed into humus by the micro critters (bacteria, fungus) and macro critters (worms and insects) as well as by light and weather conditions.
The surface layers can vary in thickness, decomposition rate, nutrient content and diversity and this biomass provides a continuous energy source for these micro and macro organisms to break down organic matter into the soil food web as well as making food more bio-available for plants to take up. These layers also capture and store moisture, prevent water loss via evaporation, prevent erosion due to runoff from harsh rains and provide habitat for a variety of soil organisms. Rich humus acts as a giant sponge and storage tank, holding the moisture in the ground.
The soil food web in living, healthy soil is a highly sophisticated, biologically active, interconnected and interactive environment of untold billions of busy soil organisms that are continually eating, digesting, multiplying, gas converting, pooping, tunnelling, etc.
These critters are the fungal and bacterial microbes, worms, insects and other microscopic organisms, all playing a critical role in the soil health and structure and dependent on each other for survival. In another words – this is an ecosystem and a habitat that these soil dwellers have created for themselves and we don’t what to muck with it by digging, flipping and tilling it all up.
It might look nice and tidy and weed-free afterwards, but you’ve just collapsed or destroyed this entire world. Over and under-watering, using toxic fertilizers, pesticides and herbicides will also collapse this ecosystem. So leave it alone, just like nature does.
The mulches being used today can be broken down into 3 basic categories: the good, the bad and the ugly. Gardeners, landscapers and farmers cover their gardens with all kinds of materials such as stones, gravel, lava rock, bark mulch, sawdust, wood and bark chips, straw, hay, grass clippings, manures, crop residues, pine needles and cones, leaves and if they’re lucky, seaweed. Just about all of these mulches lack the nutrient diversity (that’s key) needed for healthy soil conditions. Some, like grass and sawdust, can seriously reduce the amount of water from penetrating the surface due to matting, and bark mulch can actually repel water. Aggregates can cause heat stress and weeding problems and others create an imbalance in the nutrient content of your soil. Landscape fabrics starve out the soil food web, reduce water penetration and good luck trying to untangle a plant from it or weed from it.
In order to reap the same benefits as nature’s gardens, mulch your garden and landscape beds with a two to four inch layer of a nutrient-rich variety of organic matter. This will create the right conditions for a healthy ecosystem, which has its’ own natural mechanisms for combating pest and disease problems. Wait until the frost has left the ground in the spring before spreading it on your beds and then once again in the fall.
What I do is spread a layer of rich, nutrient-diverse compost over the beds, then top it off with a layer of mulch consisting of a good nitrogen/carbon mix of fresh grass clippings, shredded leaves and year-old wood chips (which allows for better water penetration). My plants stay healthy and pest-free, I rarely have to water and my beds look dark and attractive.
My gardens are full of life, just like nature’s gardens. All I have to do is give them a healthy, nutrient-diverse food supply, and they take care of everything else.
