En EspaÑol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Possibility of hydrophobic soil in Austin, TX.

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
Not Yet Rated

Wednesday - July 13, 2011

From: Austin, TX
Region: Southwest
Topic: Compost and Mulch, Watering
Title: Possibility of hydrophobic soil in Austin, TX.
Answered by: Jimmy Mills

QUESTION:

I believe I have an area in my garden with “hydrophobic soil”: no matter how much or how slowly I water, it just beads up and rolls off and the soil beneath remains cement dry and powdery. In my reading on the internet, it suggests using a very dilute solution of soapy water (1 tsp soap to 5 gallons of water), to decrease the surface tension, but it seems this is only a temporary fix for the next watering. I also read that bagged bark mulches can be the cause (I have been using bagged native Texas bark for several years. What are your thoughts?

ANSWER:

I must admit that I hadn’t heard of “hydrophobic soil” until I read your question and started looking on the web for an answer. How large an area are we looking at? This may influence the remedy that you choose.

Lets start by looking at soil in general. This article from Bachman’s Gardens gives a good overview of the nature of soil, its components, and the role of soil texture (ie particle sizes) in determining its water holding capacity. Generally, sandy soils allow more percolation than soils with finer particles.

This link from the University of Florida answers the question that I had:”What is hydrophobic soil?, suggests a possible cause, and offers mulching as a remedy.

A link from treesfoundation.org  (starting with the third paragraph) describes how hydrophobic soils can be the result of wildfires.

One possible remedy for hydrophobic soils is the use of non-ionic surfactants on the soil (University of North Carolina).

This forum from Gardenweb.com has comments from those who prefer the use of surfactants (soapy water) as well as those who propose changing the texture of the soil eg. adding mulch or compost and spading in the organic material.

I am partial to the latter, depending on the size of your garden plot.

Another source of information is the folks at the Travis County Office  of AgriLife Extension.



 

More Watering Questions

Brown, dry leaves on weeping willow tree
May 01, 2008 - We live in central TX and have just planted a weeping willow tree. Our back yard has a retention pond and ravine that parallels our property and we were told that the weeping willow will do perfectly ...
view the full question and answer

Trumpet Vine Dropping Buds
July 25, 2013 - My trumpet vine is dropping its buds before flowering. This happened last year as well. Do you know what is causing this and what I can do to prevent it?
view the full question and answer

Watering Houseplants with Soapy Water
August 22, 2011 - I accidentally watered my house plants with a container that had a some dishsoap in it. Will they be okay? One of the plants is a 20yr old cactus, with small roots.
view the full question and answer

Redbud leaves turning yellow in mid-summer
July 13, 2012 - The leaves on our redbud trees are turning yellow. The yellow leaves are pale with no other spots and no dark veins. I don't know for sure which variety of redbud they are or how old they are (more t...
view the full question and answer

Is sulfurous well water affecting leaves on trees in Belton TX
November 07, 2011 - We installed an irrigation system for our buffalo grass lawn last spring. The grass is fine but the leaves on the trees are burned where the water hits them. I suspect that the well we are using fo...
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