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

Small tan balls on oak from Pipe Creek TX
May 21, 2014 - Dear Mr. Smarty Plants, our spanish oak is growing tan colored lumpy balls about the size and weight of a marshmallow..sometimes just one at the end of a short stem and sometimes 2-3 clumped together....
view the full question and answer

Help for Collapsing Tradescantia
August 14, 2013 - My tradescantia has completely collapsed at the crown. The stems are yellowish. This happened once before when I had it planted in full sun and I just had to discard it. This time I have one plante...
view the full question and answer

Smarty Plants on mockoranges
May 25, 2005 - I live in Colorado where it is common to have 1 or 2 late frosts. I planted 4 littleleaf mockoranges (Philadelphus Microphyllus) 2 years ago and they are pretty much in full sun most of the day. I h...
view the full question and answer

Blackened leaves on purple sage in Utopia TX
December 08, 2010 - I live in Utopia Texas and have a 5-ft. Texas Purple Sage that has developed a black appearance on the leaves. What is this and what can I do about it?
view the full question and answer

Effect of unusual wet weather on desert willows
July 23, 2007 - I live in North Central Texas and have 3 beautiful Desert willow trees that are usually in full bloom. I've kept them pruned to form a nice full tree shape but now they are losing leaves and looking ...
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center