Native Plants

Q. Who is Mr. Smarty Plants?
A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

rate this answer

Sunday - November 23, 2008
From: Houston, TX
Region: Southwest
Topic: Soils, Green Roofs
Title: Soil mixes for green roofs
Answered by: Nan Hampton
QUESTION:
We are trying to set up a green roof system on our own. What do you suggest for soil? It seems the soils are proprietary and unavailable to individuals.ANSWER:
Mark Simmons, Ecologist at the Lady Bird Wildflower Center, suggests the following recipe: 50% expanded clay, shale, or perlite; 30% decomposed granite; and 20% rice husks or another fine, slowly-degradable organic matter. There are other mixtures that also work. For the Seattle City Hall green roof the "Roof Garden Soil Mix was: "55% PermaTill 5/16" Expanded Slate or equal, 30% USGA Root Zone Sand, and 15% Approved Compost." Greenroofs.com suggests a mix of "1/3 clean topsoil, 1/3 compost, and 1/3 perlite or other inorganic material" for an economical option, but this has the potential for being heavier than some other mixes.
If you visit the Greenroofs.com directory page and choose the category "Suppliers>Individual Components>Growth Media", you will find a list of companies that sell soil mixes for green roofs. I checked one, ERTH Products, that advertised "ERTH-HydRock Lightweight Structural Soil" described as "an engineered soil designed to be lightweight for use on structural conditions such as roof top gardens." Another company, Permatill, offers "Green Roof Planting Media". There are more companies listed under the "Growth Media" category. Also, you can find more information about green roof soils by Googling "green roof soil".
More Soils Questions
What grows in Tampa FL
July 01, 2013 - Please let me know what grows in the backyard in Tampa, FL to provide screening and privacy?
view the full question and answer
Coffee grounds as mulch into vegetable beds
February 05, 2009 - Can you put too much coffee grounds as mulch into vegetable beds?
view the full question and answer
Deer resistant plants from New Braunfels TX
August 31, 2012 - I have a 1/2 yard covered by a tree, shady. Bermuda grass previous owner planted has all turned brown this summer. I don't have lots of money to work with but would love to landscape that side of fr...
view the full question and answer
Possibility of growing oak-leaf hydrangea in Comal County, TX
January 08, 2005 - In the last issue of the magazine, there was an item about the oak leaf hydrangea which stated the plant's habitat is east of the Mississippi River.
Can it be grown in Comal County? Any special nee...
view the full question and answer
Destructive landscape crews in The Woodlands TX
October 20, 2012 - Hi. We need help. We recently moved to a house where landscape crews have been blowing away the leaf litter from the front yard for many years. The underbrush was also cleared long ago. The result...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |