Question
Tom,  I know South Florida is not your neck of the woods but I thought you might have an answer anyhow.
In the last two years or so my St. Augustine lawn seems to have deteriorated quite a bit. Some areas are overtaken by weeds and I feel I am losing control of the situation.
I am no fan of chemical intervention for many reasons and have stayed away from it so far.
Do you have any suggestions how I could take care of this problem?
Bianca Pratorius
Miami, Florida

Answer
Bianca:

A tough question.

Using manual methods, the physical removal of weeds may not be effective.  I know of a homeowner who decided to use hand weeding as his after work therapy.  Every day, he put on his jeans, got down on his knees and hand weeded the lawn in sections defined by strings stretched form one side of the yard to the other.  The yard was an acre more or less.  I know that this is a personal and extreme choice, but may be the only non-chemical method to achieve the goal.

The type of weeds you have in south Florida are perennial for the most part.  This means that they will return unless the roots are removed and you have no winter to do work for you.

You mention chemical intervention.  Some addicts beg for  intervention, but, most importantly, the health and coverage of your St. Augustine will prevent weeds from emerging.

Be attentive to mowing height, 2.0 - 3.0 inches, fertilization, and watering needs.  Replenish the stand where it is wanting with a good variety.  Floratam, Raleigh and Seville are mentioned as good for your area.  Make sure the pH is below 7.5 and that you have good drainage.

When fertilizing, add one pound if nitrogen per thousand square feet every month and have the soil analysed to see if it needs iron.  A high quality compost can take care of these requirements.  It should be applied at one cubic yard per thousand square feet once a year toward the end of the season.

Should you decide to do an intervention, you can use 2-4D, MCPP or dicamba for weed control.  This can be an interim strategy until the lawn covers well enough to keep weeds out.

Best wishes, preatorian.  Guard your lawn well.