En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Changing the pH of the soil

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.

Need help with plant identification, visit the plant identification page.
 
rate this answer
3 ratings

Monday - January 16, 2012

From: Austin, TX
Region: Southwest
Topic: General Botany, Soils
Title: Changing the pH of the soil
Answered by: Nan Hampton, Barbara Medford and Joe Marcus

QUESTION:

Hi, We have a job that has mostly Texas native plants on it. The architect is wanting to drop the pH levels of the soils to acidic levels that we don't feel is good for the plants and the area. Could you please contact me so I can send you the plant list and get your recommendations for the soil pH for the various plants? Thanks.

ANSWER:

The soils in Austin/Travis County are highly alkaline and the native plants of our area thrive on this soil. So, the fact that the architect wants to acidify the soil says to me that he intends planting non-native cultivars or, at least, plants not native to this part of Texas.  They will look beautiful for a short period of time until the pH of the soil begins to go up as the acidity of the soil declines—and it will definitely decline.  The soil will gradually return to its original alkalinity, probably within just a couple of years, and the acid-loving plants growing there will begin to sicken and probably die.  Additionally, acidifying the soil would likely have an adverse effect on the native microfauna living in it that are essential for healthy plant growth.  The plants native to Central Texas are not going to do well in the acidified soil and the non-native plants that start out doing well are not going to do well for very long as the acidity weakens.

You will find that the majority of the plant species pages in our Native Plant Database contain a description of the soil requirements for the plant under the heading "Growing Conditions".  For instance, on the pages for both Sophora secundiflora (Texas mountain laurel) and Cercis canadensis var. texensis (Texas redbud), under GROWING CONDITIONS, you will find:  "Soil pH: Alkaline (pH>7.2)."  You can search for the pH values of the native plants on your list in our Native Plant Database.  It is easiest to search by the plant's botanical name.  If the pH level isn't given for the plant you are looking for, then your best bet is to search the internet using the plant's botanical name.

Our recommendation to you is to use plants that are native to Central Texas.  Their pH requirements will be met by the existing soil and there will be no need to acidify it.

 

More Soils Questions

Trees for clay soil from Charlotte TX
August 25, 2013 - We have an area in our yard that even Esperanzas won't grow. It is near another that does great. Six Esperanzas are planted in a north/south row about with 10' between plants, the southern most plan...
view the full question and answer

Replacing a Grass Lawn with Moss
January 02, 2010 - I have a small north facing yard that I would like to change from grass to moss. There is some moss now but still lots of grass. I need to rake a lot of leaves in the fall but want to get away from a ...
view the full question and answer

User comments on soils from Austin
July 02, 2013 - You had a question this month about chlorosis in a Mexican plum in Bellaire. You correctly, in my opinion, answered that the problem was most likely overwatering. However, I just wanted to point out a...
view the full question and answer

Soil improvement near Kerrville, TX
December 11, 2010 - We live in the Kerrville area; the soil is extremely shallow and deficient. The yard consists of mainly native plants, with a concentration of plants for butterflies and birds. What kind of soil and ...
view the full question and answer

Area needing soil amendment in San Diego
December 02, 2009 - I have a dirt area in the corner where my fence comes together. The dirt is clay-like and during the winter the area gets very little, if any, sun and during the summer it gets 4-6 hours of sun. Wha...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center