Host an Event Volunteer Join Tickets

Support the plant database you love!

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.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

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.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
3 ratings

Sunday - May 24, 2009

From: Dallas, TX
Region: Southwest
Topic: General Botany
Title: Plants for soils with extreme pH values
Answered by: Chris Caran and Nan Hampton

QUESTION:

I am doing a project on acid and alkaline on the ph scale but all I can find is a range of 5.0 to 8.0. Do they have plants in the range of 8.0 to 14.0 or 1.0 to 5.0? If not, why is that? If so, what are they?

ANSWER:

Using the standard method of testing specified by the Natural Resource Conservation Service (NRCS), part of the US Department of Agriculture (USDA), most soils do indeed yield pH values in the range of 5.0 to 8.0 or slightly higher, although soils in some parts of the world commonly have higher or lower values.  This pH range is related to: 1) the stability of common soil-forming minerals; 2) a soil's capacity to retain and release moisture and nutrients; 3) the processes by which certain hazardous materials become concentrated in the soil; 4) the viability of many disease organisms (especially fungi and bacteria) affecting particular plants; etc.  It is for this host of reasons that soil pH is an important factor in plant health.

Few plants grow in soils with pH values far outside of this "optimal" range, although there are a few specialized plants and plant communities that require somewhat higher or lower pH conditions.  I doubt, however, that there are any vascular plants that normally live and reproduce in soils with pH values below approximately 3.0 or above approximately 9.0, although some non-vascular plants may tolerate values slightly outside of this range.  Some "extremophyle" microbes (certain bacteria and photosynthesizing cyanobacteria, etc.) and even a few invertebrate animals live in waters with pH values of 2.0 or below or above 9.0.

There are, of course, regional and local variations in soil pH, which are primarily related to the nature of the underlying bedrock and sediment, seasonal variations in precipitation and temperature, soil drainage (i.e., persistence of water saturation), etc.  The pH values for soils in any given area therefore generally fall within a relatively narrow range.  Naturally, the plant life native to each area is adapted to grow in soils with those particular pH values, at least in part.

Here is a list from Colorado State University of acid-loving plants, some of which have ranges down to pH 4 and more information from University of Hawaii about why acid soils are not favorable for plants.

You can find more information by googling "acid tolerant plants" and/or "alkali tolerant plants".

 

More General Botany Questions

Every plant in Texas
December 01, 2008 - Do you know every plant in Texas? Alexis
view the full question and answer

Where do snake herb and skeleton-leaf goldeneye get their names?
October 05, 2014 - Dear Mr. Smarty Plants, Where does snake herb, and skeleton leaf goldeneye get their names from? Thank you.
view the full question and answer

Starting a sweet potato in water in Duluth MN
April 11, 2011 - I am trying to start a sweet potato plant in water. I noticed 3 days after it's in water, there is white finger like(hairy) areas at the tip of the bottom of the potato and also on the sides. I have...
view the full question and answer

Smarty Plants on Hypogon
March 22, 2005 - How many sides does a hypogon have?
view the full question and answer

Differences in Plant Growth
November 28, 2010 - How do plants grow differently?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.