The Soil Food Web- Mulch, Compost Tea &, Mycorrhizal Relationships

As we understand that the soil food web is the foundation that creates the soils needed to support healthy, sustainable plant life, we will explore the importance of fungal compost, compost tea and mycorrhizal fungi and their relationships with the soil food web and maintaining trees, shrubs and perennials.

Just a reminder, trees, shrubs perennials prefer their nitrogen in forms of ammonium, not nitrate.  If you have ever wondered why your picea pungens (blue spruce) did not survive in the middle of your turf grass, the major contributor probably was your turf grass lawn as it is nitrate-fertilized.  By early detection or knowledge, you might have been able to protect your spruce by creating negative lawn area, in this instance, a planting island.

Mulches, fungal compost and tea work best on maintaining the health of your shrubs, trees and perennials.  When applying amidst your trees, you’ll want to make sure there is negative space between the compost and the trunk so the microbes aren’t in contact with the trunk, so the microbes don’t attack the bark.  It also makes perfect sense, both now and for future maintenance, to create planting or greenspace under the trees in place of turfgrass.

If you look at nature, leaves fall and cover the roots, naturally recycling the nitrogen and carbon with some making it back to the plant.  By applying a form of mulched leaves within a layer of brown mulch, preferably a couple inches thick, it will provide slow release nutrients and protect the roots though the winter months.  By applying a compost tea in the fall and once again in the spring (about 2-3 weeks before your shrubs and trees leaf out) is a sustainable way to insure the health and integrity of your plants and trees.

Mycorrhizal fungi products have been around for nearly a century but have mainly become main-stream within the last 5 years.  It is a natural form of nitrogen, one that envelopes and takes hold on the roots of your plants and is created by plants.  Hardwood trees form mycorrhizae known as ectomycorrhizal where most shrubs, perennials and softwood trees form mycorrhizae with endomycorrhizal fungi.  The heath family, which includes rhododendrons, sub-specie azaleas and blueberries, thrive on mycorrhizal fungus. 

If your garden is mature and you have compacted soils without noticing mycorrhizal activity (mushrooms growing under the drip line of your trees) you may wish to use a deep root feeder to inject your mycorrhizal drench to inoculate the roots.  With shrubs and perennials, it is simply excavating around their drip lines into their root zones with a spade or trowel and applying Endomycorrhizal spores.  If you have mushroom growth in and around your trees drip lines, then your soil has not been degraded to the point where natural mycorrhizal has been effected and you don’t necessarily have to add to create one.  Mycorrhizal fungi spores must be in contact with roots within 24 hours after exposure to moisture to grow and this is why mycorrhizal fungi is applied as a drench to assist in their delivery.

By applying mulches, teas, composts and mycorrhizal, your trees, shrubs and perennials will be less stressed and keep them from becoming attacked by insects.  They create extra pitch; their leaves are coated with beneficial bacteria and fungi to outcompete disease.  By having a soil food web –based system in place, you will continue to build a sustainable foundation for a healthy garden and greenspaces. If your plants do become stressed or diseased, at the first sign, don’t hesitate to put your soil food web knowledge to use and re-apply, especially compost teas. 

The Soil Food Web & The Relationship to Healthy Soil

To support sustainability, a good foundation is necessary.  Just as important as a well constructed building foundation, the soil food web is the foundation that creates the soils needed to support healthy, sustainable plant life.

Good soils are teeming with life, from earthworms to centipedes and ants, there is a world of soil organisms such as fungi and bacteria in which every organism needs energy to survive.  They derive this energy from nitrogen and sulfur and carbon that is produced from plants and waste products produced by other organisms.  The soil food web, beneath and above the soil is simple eat and be eaten existence.  Organic matter produced by healthy plants and root systems create organic matter that is turned into bacteria (subsurface) while fungi is being created closer to the soil surface.  In a cross-linked soil food web, root and fungal feeding nematodes are then preyed upon by birds which in turn are preyed upon by larger animals.  To simplify, it always starts with the plant.

Plants secrete chemicals that are important to the soil’s condition, through photosynthesis in the leaves and these secretions are referred to as 'root exudates'.  These carbohydrates exudated by roots grow beneficial bacteria and living fungi which commences the food web.  These beneficial bacteria and fungi are natural fertilizers for healthy plants and are spread by nematodes by eating the bacteria and fungi, digest what they need to survive and excrete excess carbon as waste.

As we gardeners all know, not all soil bacteria and fungi is beneficial and many cause plant diseases.  Having good soil food web containing a large, diverse population of different species will help control theses non-beneficial troublemakers.  This healthy soil food web will keep these pathogens in check and in some instances to their deaths.  Mycorrhizal fungi is a special soil fungi, interacting with roots, producing nutrients such as water, nitrogen and phosphorous.

The importance of understanding the soil food web, the foundation of good soil, is to also understand the negative impacts on the soil food web.  Chemical fertilizers, pesticides and insecticides affect the soil food web in a negative way, toxic to some and chasing others away.  You have now started altering the soil food web as you will have to continue to use chemical fertilizers and pesticides as plants microbial method of obtaining nutrients has been affected by reducing the natural fungi and bacteria and chasing away a major contributor, the earthworm. 

The living organisms within the soil food web will be continuously at work, building defenses against pests and disease, creating soils that drain well and pathways for oxygen and carbon dioxide.  By employing soil food web knowledge, you can reduce / eliminate the use of commercial chemicals and fertilizers, improve your soils overall health and usefulness and start building a sustainable foundation.

Next blog release, we will discuss the soil food web and its important relationship with compost tea, mycorrhizal and maintaining trees, shrubs and perennials.

Beautiful, Animated and Bio-diverse- Ornamental Landscape Grasses

As far back as the early 1900’s, gardeners from a wide range of climates have been enjoying various species of perennial ornamental grasses in their landscape.

Ornamental landscape grasses allow us to rapidly change the dynamics of our landscape, creating works of art by maximizing various colors, textures and physical characteristics of the specie or species selected.  They allow us to be conserving (as most are drought tolerant once established), high spirited, inspiring and maximize out time management by offering low maintenance.

In the broad sense, ornamental grasses (including sedges and rushes) are ever expanding, as the grass palette which started with maybe a dozen perennial grasses to choose from in the early 1900’s has increased to over 100 exhilarating choices.  The increase in diversity and ease of day-today care, the popularity of ornamental landscape grasses has never been greater, reflecting the rhythms of our shared places, of the sun, and the seasonal change.

The two main growth habits of grasses are referred to as runners or clump forming.  When applied appropriately, running grasses can minimize maintenance as they knit together stabilizing soils and making excellent groundcovers.  When used in the wrong situation, you can imagine the problems that might be created, as these runners take over less vigorous neighbors creating monocultures instead of the diverse garden you were hoping to create.

Tufted grasses, as some clump grasses are referred to, grow slower and their space within the garden is easier to determine and many clump forming grasses make excellent architectural pieces, such as Calamagrostis ‘Karl Foerster’ and Pennisetum orientale ‘Lil Bunny’.

When discussing ornamental grasses growing seasons, grasses are typically referred to as cool-season growers and warm-season growers.  Their periods of growth are determined by temperature, days of sunlight and soil temperature.  Cool season grasses grow well from sub-freezing temperatures into the low 70’s as warm-season grasses respond well to hot weather, superbly adapted to temperatures reaching the mid 90’s.  The hotter the day, the more they revel, growing steadily larger and producing magnificent flowers (awns) at summer’s end.

The almost over-looked aspect of maximizing landscape grasses is they continue to pay forward, as over the years most ornamental landscape grasses can be divided with a knife or narrow edged trowel and discarding the dead material will provide a healthy and strong plant the following spring.

Creating Your Kitchen Garden

Trying to stay true to the earliest medieval kitchen garden, le potager (vegetable garden with deep historical tradition), is about understanding them, and not trying to re-create them.  It is about simplicity, becoming self dependent on fresh authentic food.  It is about balancing spirit and soul.  

Our kitchen gardens should be paradise, a mainstay of our everyday landscape, not a disjointed separation of space.  It should be an artistic expression of you, your passion and personality.  This can be achieved from layout through the plants that you choose to grow, from vegetables to perennials. 

There are a few main things to consider when designing your potager such as site conditions (sun angles, micro-climates), the amount of space you wish to develop, your maintenance and harvest of your kitchen garden, watering, fauna, and proximity to your kitchen as a well placed potager is an extension of your kitchen, not placed in the ‘back forty’ of your property.  Are you going to create raised gardens within your kitchen garden (preferably) and how are you going to create your welcome mat, your entry piece that tells people they are welcomed, and please enter?  his can be accomplished by a simple trellis planted with grapes or simpler yet, a gate attached to a free standing pole that is always open, mingling with a hedgerow of lavender.

Infuse art into your kitchen garden, by adding colored planting vessels or a bright blue picnic table immersed in monochromatic hues of green background such as pole beans (Phaseolus vulgaris) hops (Humulu lupulus) and hardy kiwi (Actinidia argula).  Create intrigue by developing a secret garden within your kitchen garden, a light and airy space, a place to escape the day – to – day routines.  A place enclosed by an edible wall of elderberries, with a fountain and a place to rest.

Plant plants that nourish beneficial insects such as anise hyssop (Agastache spp) coneflower (Echinacea) and bee balm (Monarda) to name a few.  Have fun, be creative and always remember never plant from the same family in the same space in successive year.

LEED Application in Sustainable Landscape Practices (second in a series)

Credit 7:  Landscape and Exterior Design to Reduce Heat Islands

Sustainability begins with design; clear, precise design objectives with long term management objectives.  Long term planning and management to reduce heat islands, is a LEED accredited application that can be obtained by several design methods.  Heat island effects are caused by solar energy retention on constructed surfaces in urban areas, elevating the temperature differential between urban and rural environments between 2 and 9 degrees.  Streets, sidewalks, parking lots and roofs are the primary contributors.  The increased urban development and rising temperatures caused by heat island effects also has proven to have a negative effect on wildlife and their habitats.  Mitigation techniques include maximizing shade-producing vegetation that can increase shade during all seasons to combat varying sun angles and by reducing heat island effect by increasing shade by 30 percent will meet LEED certification requirements.  Vegetation will reduce solar absorption on non pervious surfaces and also cool the air through evapotranspiration (commonly referred to ET).  Using an alternative material for paving or concrete that has a high-albedo solar reflecting value of 0.3 or higher will also reduce the heat absorption that leads to heat islands.  Materials such as subsurface grasscrete (a structural grid / paver installed below grade that is typically planted with vegetation) and turfstone pavers planted with vegetation are perfect alternatives to your traditional paving materials, allowing you the flexibility to reduce heat absorption and the cost per square foot is typically lower to install.  Green roofs and living walls will mitigate heat island effects and create passive solar and currently only green roofs are recognized certified LEED when a vegetated roof envelops at least 50 percent of the roof area.  Living walls are currently being reviewed by the LEED program and will be recognized and accredited in their new standards scheduled for release in 2012.

Innovation in design is a LEED certified application and by choosing sustainable design topics such as heat island reduction within a sustainable site, the accredited value for LEED recognition continues to increase.

Resources:

Heat Island Group Lawrence Berkeley National Laboratory:  http://eetd.lbl.gov/HeatIsland/

LEED Application in Sustainable Landscape Practices

Part 1 of a Series

Leadership in Energy and Environmental Design (LEED) was first released for new construction in 2000.  It defines high standard / high performance green building promoting environmentally responsible, healthier, and more profitable building projects.

New rating systems continue to be developed for different building types, and currently there is not a rating system devoted purely to landscape and landscape architecture.

 

Each of the rating systems assumes a “whole-building design practice,” with a primary use building associated to site planning.  For instance, a pure landscape architectural project such as a park would not be excluded; it would not score a certification as high as if there was a structure on the site.  The good news, as the LEED system is being re-evaluated to contain and recognize more landscape elements to be certified, currently landscape architecture elements and site planning can be responsible for contributing up to 43 points to a project.  The point valuation system is given in the “LEED-NC Version 2.2 Registered Project Checklist”.  For quick reference, LEED certification levels are listed below:

Certified 26-32 points

Silver  33-38 points

Gold  39-51 points

Platinum  52-69 points

Over the next several releases of this blog, I will discuss the potential applications of LEED-NC (NC standing for ‘new construction’) within the scope of the landscape profession beginning with some of the more common categories within Sustainable Sites which has the potential to earn 14 points.

The prerequisite of any project should be to develop an erosion and sediment control plan which reduces negative impact on water and air quality.  Urban redevelopment is also defined in LEED accredited sustainable sites, encouraging development in urban areas with existing infrastructure and reduce site disturbance by restoring 50% of remaining open area on previously developed sites by planting native or adapted vegetation.

Stormwater management is a critical part of any sustainable site, including the use of permeable materials such as permeable pavers; those of you who have worked with me understand how valuable permeable pavers are in residential and commercial sustainable landscape.  Permeable materials can decrease run-off by a minimum of 70% with most permeable surfaces reducing run-off by 85% which removes the strain from storm water systems that are now insufficient due to urban and rural growth.  I will return to permeable pavers in future blogs to discuss in greater detail including proper installation methods of permeable pavers.

 

The more training and experience I have with such sustainable practices allows me to play a leading role in promoting and implementing these sustainable landscape practices.  The more I become a “systems thinker” (the ability to work with and see connections with other disciplines) and my environmental mind-set, the potential to increase LEED accredited landscape awareness becomes a way of life.

Creating Your Peaceful Retreat- Landscaping for Privacy

There are many factors we face creating privacy within our landscape, from buffering sound, preventing trespassing, creating windbreaks, reducing noise pollution, keeping unwanted wildlife at bay to screening unwanted views.  Over the years I have been able to create innovative ways that can help you create your sense of space and a peaceful retreat, even in small space areas.

Our greenspace areas have always been that one place we long to keep life’s everyday disturbances to a minimum; a place to feel protected and our retreat from the aspects of the modern world.  Creative ideas will turn your landscape into an extension of your home, whether it is an urban courtyard or a 10,000 square feet corner of your property, through thoughtful design, not quick fixes, there are sustainable and obtainable solutions that fit in seamlessly.

When buffering is accomplished correctly, it will create the impression of distance, an illusion of separation and reflect your personal style.  Vegetation layering, maximizing conifers and deciduous trees will create seasonal color, textures and privacy.  Simply changing elevations in your narrow greenspace with rolling berms and boulders instantly creates depth and the sense of buffering and privacy and these are perfect for planting seasonal bulbs, like deer resistant Alliums such as ‘Purple Sensation’, ‘Mars’ and ‘Gladiator’.  Utilizing planting vessels is another solution to establish screening and privacy while expressing your creativity and adding color to small space areas.  Groupings of colorful vessels with billowing Hydrangea spp. will mask noise and offer you the luxury of seasonal cut flowers.

In areas where larger space is available to create privacy, small space, mounding evergreen plants such as Pittosporum tenuifolium, Ilex crenata ‘Northern Beauty’ and Chamaecyparis obtuse offer many flexible and interesting colors and textures.  These are perfect plants for maintaining sightline corridors or as understory of trees, as they typically will not grow above 4’ in height.

There are other ways to help buffer road noise pollution such as an energy efficient low flow water element mixed amongst evergreen screening, such as Pinus flexalis ‘Vanderwolf’.  A properly placed water feature, located near the main ‘listeners’ area, such as outside the master bedroom window or somewhere positioned between you and the unwanted noise, creates peace and tranquility in small urban settings while removing unwanted noise.

Solutions for reducing fauna and other trespassers without constructing overwhelming and cumbersome wood fences would include trellises and arbors, maximizing wonderful vines such as Clematis, Lonicera, and Wisteria species.  Espalier ‘living walls’ using Pyracantha ‘Government Red’ provides a narrow, yet dense wall producing a food source for birds in the fall and winter.    In milder climates, planting a thicket of Optunia will deter intruders while adding architectural interest and wonderful color when they are in bloom.

For a complete list of versatile plants for small space screening, please contact me at eric@florapacifica.com