En EspaŅol

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
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 - January 12, 2011

From: Gilroy, CA
Region: California
Topic: Compost and Mulch, Diseases and Disorders
Title: Getting rid of algae on dirt and patio
Answered by: Nan Hampton

QUESTION:

Algae and on patio and dirt, and how to get rid of same?

ANSWER:

I'm guessing you meant to say "algae and (moss) on patio and dirt".  Am I right?  If you have either one in such a situation, you usually have both.  The reason they are growing there is that they are experiencing continuous moisture and very little sunshine.  Those are two of the major requirements for algae and moss to grow.  First, we will talk about your soil.  Poor drainage is very likely a major factor with soil that remains moist.  If your soil is very dense and compacted, aerating it and adding compost and/or mulch to it will improve its drainage.  The University of California Cooperative Extension Service has an article, "Moss and Algae Do Well in Wet Weather and Poorly Drained Soils", that offers other suggestions for eliminating algae and mosses which include applications of copper sulfate, ferrous sulfate or ferrous ammonium sulfate.  Another recommendation from the Yard Doctor: Central Northwest suggests using sodium hypochlorite (or copper sulfate) in a 1% or 2% solution to spray the area.

If you Google the terms "eliminating algae from patio", you will get lots of suggestions for removing algae from patio bricks which include power washing, dilute bleach solutions and algaecides.  Again, changing the elements that cause the problem (poor drainage and too much shade), are important in order to keep the algae from returning.  How you remove the algae depends on the size of the area, the intensity of its growth and what plants or structures are nearby that might be impacted by the treatment.  Here are a couple of sites that have suggestions:  from Desmesne and from the Royal Horticultural Society in the UK.  You can consult a reputable local nursery or home supply store to find the most effective and ecologically responsible algaecides.  I would also suggest you contact your Santa Clara office of the University of California Cooperative Extension Services for suggestions for removing the algae.

 

More Diseases and Disorders Questions

Beetles in spineless prickly pear in Austin
June 05, 2010 - I have an enormous spineless prickly pear in my front garden. It's about 6 feet tall, and 6 feet wide. It has blossoming yellow flower. However, it also has large colonies of black beetle-ish bugs li...
view the full question and answer

Acid rain in Ft. Worth?
August 19, 2010 - ALERT. NEED IMMEDIATE ATTENTION. Why are so many trees, plants, etc. in the Fort Worth area dying?? I heard acid rain. Please don't say drought. I have lived in this area all my life and survived t...
view the full question and answer

Yellowing foliage on a lemon cypress from St. Charles MO
May 22, 2011 - I recently received a lemon cypress tree as a gift. After about a month we transplanted it outside and the foliage turned from a light green to a yellow color. Is this normal? The tree doesn't app...
view the full question and answer

Yellowing leaves on non-native globe willow in Las Cruces, NM
June 26, 2010 - I live in Las Cruces, NM. I have a good size globe willow tree. The leaves are turning yellow and brown dryness at tips and leaves are falling off. Does it just need water?
view the full question and answer

Care of Jade plant
September 06, 2007 - Hi there, I have a question and really appreciate your time helping me regarding my plant. I bought a Jade plant; 35 yr. old ; very thick stems and healthy at the time of purchase from a very si...
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