Navigation Links
How does your green roof garden grow?

UNIVERSITY PARK, PA -- Growing plants on rooftops is an old concept that has evolved from simple sod roofing to roof gardens and new, lightweight "extensive green roofs". Modern green roofs have environmental and social benefits; they can reduce stormwater runoff, improve air quality, mitigate urban heat, reduce the demand for air conditioning and greenhouse gas emissions, and provide habitat for birds and wildlife. Long-used in urban planning in Europe, green roofs are becoming more popular in North America, and new research designed to promote the integration of green roofs into current and future buildings is burgeoning. Researchers from the Department of Horticulture at The Pennsylvania State University published a study in HortTechnology that evaluated the influence of substrate type and depth on establishment of five common green roof plants.

Plants suitable for extensive green roofs must tolerate extreme rooftop conditions, and the substrates in which they grow must meet both horticultural and structural requirements. Deeper substrates may retain more water for plants during dry periods, but they also weigh more, especially when near saturation. The study by Christine E. Thuring, Robert D. Berghage, and David J. Beattie was designed to evaluate the effects of substrate type and depth on the establishment and early growth of five plants popular in North American green roof designs.

The researchers hypothesized that early drought is more harmful for plants grown in shallow rather than deeper substrate depths, and that plants that survived early drought conditions would produce less shoot biomass than those subjected to late drought. Two stonecrops, one ice plant, and two herbaceous perennials were planted in three depths (30, 60, and 120 mm) of expanded shale and expanded clay, two commercially available green roof substrates. Study flats inside a plasticulture tunnel received three drought treatments: no drought, 2 weeks early drought, and 2 weeks late drought.

The two stonecrops performed well under most conditions, although tasteless stonecrop was stunted by early drought. Ice plant performed erratically and, along with maiden pink, poorly in face of drought during establishment. When subjected to any drought, the herbaceous perennials had the fewest survivors in the expanded shale. The study plants were most affected by substrate depth, except for maiden pink, which responded solely to drought. When subjected to early drought conditions, the herbaceous perennials did not survive in 30 mm of either substrate, or in 60 mm of expanded shale; early drought appeared to be more harmful to plant survival and performance than late drought. Although the stonecrops performed well in 60 mm of substrate when subjected to drought, their performance was superior in the expanded clay compared with shale.

The three most resilient species used in the studysaxifrage pink, white stonecrop, and tasteless stonecropalways produced more shoot biomass with increasing substrate depth, regardless of water availability. A standout performer was saxifrage pink, which had an attractive appearance and persistent flowering habit, making it an excellent choice as a green roof plant.

The experiment illustrates how appropriate species selection in the design of unirrigated extensive green roofs may be directed by factors such as substrate type and depth, as well as anticipated drought conditions. "This experiment revealed the variability among drought-tolerant species to various treatments, as well as the different plant responses to substrate type during drought", concluded the scientists.


Contact: Michael W. Neff
American Society for Horticultural Science

Related biology news :

1. New technology improves greenhouse, plant microclimates
2. Blue-green algae tested for treating ALS
3. Rising greenhouse gases profoundly impact microscopic marine life
4. Global rivers emit 3 times IPCC estimates of greenhouse gas nitrous oxide
5. Waterways contribute to growth of potent greenhouse gas
6. New study about Arctic sea-ice, greenhouse gases and polar bear habitat
7. Green genes in yeast may boost biofuel production by increasing stress tolerance
8. Pitt study finds green water treatments may not kill bacteria in large building cooling systems
9. Diners may be willing to pay more to eat at green restaurants
10. Greener climate prediction shows plants slow warming
11. Record-high greenhouse gas concentrations
Post Your Comments:
(Date:6/15/2016)... ALBANY, New York , June 15, 2016 ... published a new market report titled "Gesture Recognition Market ... Trends and Forecast, 2016 - 2024". According to the ... at USD 11.60 billion in 2015 and is ... and reach USD 48.56 billion by 2024.  ...
(Date:6/3/2016)... , June 3, 2016 ... Management) von Nepal ... und Lieferung hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, ... führend in der Produktion und Implementierung von ... der Ausschreibung im Januar teilgenommen, aber Decatur ...
(Date:6/1/2016)... June 1, 2016 Favorable Government ... Administration and Criminal Identification to Boost Global Biometrics System ... released TechSci Research report, " Global Biometrics Market ... Forecast and Opportunities, 2011 - 2021", the global biometrics ... 2021, on account of growing security concerns across various ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016 Apellis ... Phase 1 clinical trials of its complement C3 ... single and multiple ascending dose studies designed to ... (PD) of subcutaneous injection in healthy adult volunteers. ... (SC) either as a single dose (ranging from ...
(Date:6/23/2016)... -- On Wednesday, June 22, 2016, the NASDAQ ... Dow Jones Industrial Average edged 0.27% lower to finish at ... has initiated coverage on the following equities: Infinity Pharmaceuticals ... NKTR ), Aralez Pharmaceuticals Inc. (NASDAQ: ARLZ ... Learn more about these stocks by accessing their free trade ...
(Date:6/23/2016)... ... June 23, 2016 , ... Velocity Products, a division of ... and optimized exclusively for Okuma CNC machining centers at The International Manufacturing Technology ... among several companies with expertise in toolholding, cutting tools, machining dynamics and distribution, ...
(Date:6/22/2016)... SAN DIEGO , June 22, 2016 /PRNewswire/ ... partnership that will allow them to produce up ... (HiPSC) from one lot within one week. These ... their time laboriously preparing cells and spend more ... made possible through a proprietary, high-volume manufacturing process ...
Breaking Biology Technology: