Introduction

North Carolina is home to many environmental stewards. Duke University is among our states leaders in sustainable practices and excels in consistently rolling out the green carpet. .  One of these unique efforts is the Duke Smart Home – a living laboratory for students focused on addressing sustainability problems. In the landscape around the Duke Smart Home, John Deere has built a ‘Smart-Sustainable Landscape’ that typifies landscapes.

The Duke Smart Home is the first LEED (Leadership in Energy and Environmental Design) Platinum building on the campus of Duke University. LEED is a voluntary rating system created by the United States Green Building Council (USGBC). The smart-sustainable landscape around the Smart Home is a pilot project in the Sustainable Sites Initiative (SSI) a voluntary rating system that uses a similar approach to LEED but focuses on the landscape. SSI is jointly sponsored by the American Society of Landscape Architects (ASLA), Lady Bird Johnson Wildflower Center, and United States Botanic Garden (USBG). The John Deere Smart-Sustainable Landscape demonstrates how landscapes can perform as sustainable systems when properly designed, constructed, and managed and for the everyday gardener a series of common-sense ideas for generating more green beauty in your garden and more green dollars in your wallet.

My top seven sustainable tips to incorporate in a garden are as follows:

1

Greener Garden: Cadillac of Composting

Recycling grass clippings, fallen leaves, leftover produce and paper is an easy way for creating the rich soil that is required for a nutrient enriched garden.  The compost bin at the Duke Smart Home is top of the line! The back of the bin is made from chicken wire to allow ventilation and the front of the bin is wood slats (cedar) that can be easily slipped out for unloading the soil once it is broken down. The smart home composting bin is divided into sections so that waste can be sorted and micro-organisms can efficiently break down the sorted waste into rich soil. One of the best features of the compost bin is that it is built out of wood that was taken from an old cedar tree on site and milled into lumber. Any cook will tell you, if you want delicious results you must have the best ingredients possible. Successful gardeners will tell you the most important ingredients of a good garden is rich, amended, soil.  Using  a composting bin is a fantastic way to transform waste into useful organic material.  For those gardeners needing a Mini Cooper rather than a Cadillac of composting try www.compostnow.com.  They make composting easy.  They provide the pail, pick up your food-waste and drop off a new clean empty pail every week (Moms, remember the baby diaper service?) the only difference is they bring you back composted soil instead of clean diapers.

2

Greener Garden: Rain Gardens

One of the unique features of the Smart-Sustainable Landscape is that 100% of the storm-water by volume on the site is managed on the site. This is accomplished through two rain gardens that are specially constructed (and permitted) best management practices (BMP). Rain gardens, or bio-retention areas, use soil and plants in a specifically designed and/or engineering form to filter storm-water runoff on site. These BMPs are depressions filled with a gravel base that is topped by a specific type of soil media and finally a layer of organic mulch. Specific plants are then often planted into the soil media whereby the plant will remove nitrogen, phosphorus, metals, and other elements that are undesirable in storm-water runoff. The rain gardens retain and allow the water to filter through the soil media slowly before exiting the site in a cleaner form.   The plants also work effectively at helping to remove contaminants in the storm-water runoff. The rain gardens at the Duke Smart Home were engineered and built to the City of Durham BMP specifications for optimum performance. They are a great example of how performance and aesthetic qualities can be blended together for sustainable results.

3

Greener Garden: Smart Irrigation / Rainwater Harvesting

We all recognize that water is a precious commodity that needs to be used responsibly. While it is an important nutritional and sustaining element for people, it is also an important input for plants, including turf-grass – especially in cases of sustainability where the value of each plant in a landscape system is somewhat determined by measured use of water. Nonetheless, the Smart-Sustainable Landscape at the Duke Smart Home shows that one can have a sustainable, high-performance landscape that contains a balance of trees, shrubs, ground covers, and turf-grasses without using inappropriate amounts of water. To account for this, a state-of-the-art closed loop smart irrigation system was installed to use in conjunction with an extensive rainwater harvesting system.  The smart irrigation system uses an on-site weather station to collect weather data and calculate evapotranspiration (ET) rates – essentially the amount of water lost due to evaporation and plant transpiration. It also uses a smart controller that receives and schedules (based on the ET information) from the weather station information.  It also utilizes information from in-ground soil sensors that measure soil temperature and water by volume. The soil sensors give an indication of the amount of water actually in the soil and available for plant use. Jim Gaston, director of the Smart Home is proud to boast  “John Deere also installed a state-of-the-art, programmable irrigation system that uses sensors for temperature and ground moisture to help regulate watering for different zones throughout the property. The programmable irrigation system is sensitive to soil moisture requirements and waters only when and where the lawn is dry and needs watering.” While currently accepted thinking is to water off of ET rates, the information from the soils sensors has shown that significantly less water can be used to maintain healthy performing plants than what would have been determined by ET. To account for specific plant water needs, the site (less than one acre) is divided into twenty two irrigation zones. The irrigation system is supplied by rainwater (3200 gal storage capacity) captured from the Smart Home roof.

4

Greener Garden: Permeable Pavers, Recycled/Reusable Material

Another important aspect of the landscape at the Duke Smart Home is the materials that were selected. As an example of thoughtful material selection, all of the paving systems are permeable pavers which allows the water to be captured rather than allowing runoff. Paving blocks used on the retaining walls were chosen because they could be recycled, reused, and/or deconstructed with minimal labor and time. The shed at the top of the site is made from recycled wood originally on the site. And, one of the best stories on the site is how an existing dead cedar tree was cut and milled on site into lumber that was used to build the composting bins and a bench under the large Magnolia tree that was previously covered in vines and surrounded by weeds prior to construction.

5

Greener Garden: Right Plant, Right Place, Right Time

Plants in the Smart-Sustainable Landscape were selected based on their ability to contribute to the overall performance of the landscape relative to sustainability goals. They were also selected based on the adage of the right plant in the right place at the right time. A combination of adapted and native plants were used to achieve the performance goals of the site. Each selected plant or plant type in the landscape serves a distinct purpose relative to the performance goals of the site. This includes turf-grasses, which play a key role in the functional performance of the site. Three different turfgrass types were selected for use in the site (tall fescue, Tifway 419 Bermudagrass, Tifgrand Bermudagrass) to  match the climatic conditions on the site and the functional goals of the site. Both enable full utilization from the plants with the right balance of inputs to achieve site outputs (performance).

6

 Greener Garden: Backyard Orchard / Vegetable Gardens

Finding fruit bearing trees or shrubs with low maintenance requirements can be tricky for the southern backyard. North Carolina’s high humidity and hot summer nights create disease and insect problems that ravage the average apple, plum or peach trees, unless chemicals are used. When spraying is not an option, it’s good to find disease resistant plants. The John Deere Smart-Sustainable Landscape suggest a plant palette adapted to the area and climatic conditions. Muscatine grapes are native and are a great choice for the garden trellis. Blueberries are a favorite fruit and offer structure in the garden. In fact, they can be used as hedges. The rabbit eye varieties are bred from native blueberries and do well in the gardens here.  A variety of Fig trees are also a great choice for the landscape. They offer beauty and bear several crops per season. Need a ground cover? Why not try overbearing Strawberries? Edible landscaping options are a great way green up a garden, a bare spot in your yard, or a sloped hillside.

In the John Deere Smart-Sustainable Landscape,  students grow an abundance of food for their own needs and to meet the needs of others on campus. The success of this garden is due to a series of sustainable garden techniques.  The garden plots are planted in raised beds that contain a fertile soil growth medium. The beds are also surface drained and irrigated individually based on each grower’s needs. The beds are over twenty inches deep, composed of rich organic soil and amended with compost from the on-site bin. To maintain organic integrity the garden is pesticide free. The beautifully tiered, extremely productive Duke Smart Home Garden will leave you green with envy.

7

Greener Garden: Automated Mowing

Meet George Jetson and his lawnmower. In the futuristic cartoon, THE JETSON’S George and his family preferred buzzing around in his family space ship rather than taking care of his domestic chores. If THE JETSON’S had the time or the inclination to groom their space lawn, I imagine their robotic lawnmower would look something like John Deere’s Tango autonomous mower. The Tango can cut your lawn consistently and frequently. Frequent mowing provides a smart looking yard. It allows you to keep the grass long enough to shade out weeds and – through mulching, returns natural nitrogen to the soil through clippings that decompose. The automated mower can also provide for less wear on the turf, denser turf from more frequent mower, emission-free operation, and other benefits.

Mark Schmidt John Deere’s Turf agronomist contributed to this article.