Build Healthy Soil
PARTNERING WITH NATURE
A Guide to Sustainable Horticulture
Contents
Build Healthy Soil
What is healthy soil?
Plant health is dependent on soil health. Healthy soil is an ecosystem that contains a diverse community of organisms (“the soil food web”). Carefully cultivating this ecosystem is a pillar of Lotusland’s sustainable approach to horticulture. Some members of the soil food web are visible to the naked eye, i.e., plant roots, earthworms, and insects. Less apparent but vitally important are microorganisms, including protozoans, bacteria, nematodes, fungi, micro-arthropods, and other organisms. Keep in mind that what constitutes ideal soil conditions will vary depending on your location and plant selection (See: Understand Plant Needs and Garden Conditions).
In contrast to this ecologically based view of soil, conventional horticulture typically regards soil as an inert medium–little more than a substrate to hold the plant upright and contain the roots. The organisms living in soil are often overlooked unless they become a problem, in which case they are something to be swiftly eradicated. Little is done to nurture the life within the soil.
What does healthy soil do for plants?
The biological activities of soil organisms convert organic matter and soil parent material into nutrients necessary for plant growth, increasing the fertility of the soil. Through this process, they also enhance soil structure which improves drainage and increase soil’s ability to capture and hold water, reducing irrigation needs. All of this helps plants to develop strong root systems which are essential to their health. Furthermore, the increased biodiversity in healthy soils helps to suppress disease by keeping pathogenic organisms in check.
What does healthy soil do for the environment?
In addition to the benefits that healthy soils provide to the plants growing in them, they contribute to wider environmental health. To name just a few outcomes, healthy soil is:
- Less susceptible to erosion from wind and water, helping to preserve valuable topsoil.
- Better at absorbing and holding on to moisture and nutrients, resulting in less runoff that can pollute creeks and other bodies of water.
- Home to organisms capable of breaking down toxic substances in the environment.
- A carbon sink, sequestering carbon that would otherwise wind up in the atmosphere.
How do we get healthy soil?
Lotusland supports soil biology by incorporating organic matter into the soil through the use of organic fertilizers, compost, compost tea, and mulches. This organic matter is food for organisms which cycle nutrients through the soil ecosystem. Home gardeners can easily take these same steps to encourage life in the soil. Again, keep in mind that what constitutes ideal soil conditions will vary depending on your location and plant selection.
Lotusland uses only organic fertilizers derived from minimally processed, natural sources. When selecting fertilizers, look for identifiable ingredients such as meals of alfalfa, fish, bone, feather and/or kelp. Unlike synthetic fertilizers, these organic fertilizers must first be broken down by soil microorganisms and converted into plant-available forms. This results in improved soil health and steady growth which is much better for plants in the long run.
Lotusland’s 37-acre property generates tons of organic green waste every year. Much of this surplus organic matter is composted on-site: Bacteria, fungi, earthworms, and arthropods decompose the so-called “waste”, transforming it into compost, a soil amendment rich in nutrients and beneficial soil organisms. The use of composts results in improved soil biology, fertility, structure, and water retention.
Hot composting (thermophilic) is what most people imagine when they think of composting, but there are many types of composting. Even if you have limited space at home, worm composting (vermiculture) could be an option for cycling organic waste back to your plants. One starting point for learning about composting is the U.S. Environmental Protection Agency’s website Composting at Home.
From our compost, Lotusland derives a liquid extract called compost tea. This biology-rich product is created through an aerated, “cold-brewing” process, then applied to soil and foliage. The beneficial organisms contained in compost tea improve soil conditions and help to suppress plant pathogens. Compost tea can be brewed at home in a 5-gallon bucket or on a larger scale, depending on your needs. You can easily construct your own compost tea brewer from a 5-gallon bucket and a few other parts (or purchase a complete kit online). More detailed instructions on compost tea are available here.
A mulch is any material applied to the soil surface as a dressing material. At Lotusland, “mulch” usually refers to organic, plant-derived material, but it can also refer to a rock covering as is found in the Dunlap Garden, Aloe Garden, Succulent Garden, and along the Main Drive.
Covering bare soil with mulch suppresses weeds, regulates soil temperature, reduces the evaporation of soil moisture, and looks good! Over time, mulch is broken down by soil organisms, releasing carbon and nutrients which are cycled through soil by the soil food web. This cycling of nutrients eventually results in the soil-building benefits of compost — increased organic matter and improved biology, fertility, structure, and water retention.
Use fallen leaf litter from your own garden as a naturally-occurring mulch or inquire with arborists that might have wood chips available. A variety of bagged and bulk mulches are available at garden centers. Some municipalities (including Santa Barbara County) offer free or low-cost mulch to the public as a water-saving incentive. Consider the needs of your plants and the aesthetics of your garden when selecting a mulch.