Question


I have finally come to the conclusion that my lawn needs professional help. A variety of weeds are beginning to overtake my lawn almost to the point that in a few years there might not be much grass at all. Some of the weeds include clover, dandelions, plantain, oxalis, purslane, wild violet and crab grass according to his evalutation.

I called a lawn service company and inquired about going organic. They told me that was fine for the fertilizer but there is not such thing as organic weed killer and that those needed to be dealt with in addition to the fertilizer. I have worries with weed killer on my lawn with my dog going outside and using the yard as often as he does. He said that after an hour and a half that it is 100% safe for my pup to use the yard as he would any other time.

I find that somewhat hard to believe. Can you verify that the lawn is safe for people and animals to use after just s short amount of time when weed killer or fertilizer is applied? What about if I treat the lawn with lime? How long is it before the lawn would be safe to use after an application of that. The lawn service says that because lime is a mineral, it抯 safe right away. He lost credibility with me the second he said that.

Sorry to be long winded, but I want to have a nice lawn, but not at the cost of harm to my pets and family. Thank you very much.

I live in SW PA.

Thank you again.  

Answer
Mr. O'Hern:

I will discuss your questions in parts, as you have asked them.

I converted to organic over thirty years ago, having studied the effects of chemicals then.  I have not done an in depth study of the new chemicals, so I do not know of their effects on human health.  I do know that organo phosphate based products are considered bad.  However, the newer products are far more specific in their effects on plant material and not as broad spectrum as the older ones.  Further, from thirty years of pressure form the environmental community, chemical companies have become sensitive to public pressure and are producing safer chemcials for consumer use.

The use of a professional service is wise.  A service will not over apply any product.  It will abide by federal and state regulations for applicators.  It is familiar with weeds, turf and safety margins.  It will also be sensitive to public opinion for maintenance of its reputation.  These are general observations from the professionals I know and have met.  There is always the two to five percent of which to be cautious.

The weeds you describe are, for the most part, managable without chemicals.  Dandelions, plantain, oxalis, white clover, purslane will respond to cultural practices.  Cragbrass and violet are persistent, and, if you want control, you must use a chemcial product.  Violets will invade from seed and slowly expand.  Crabgrass can be replaced after renovation by strong grass population and health.

A product like Roundup, broad spectrum hormone type, is safe after it dries and has little movement in the environment.  Others, 2-4D, carbaryl, MCPP, MSMA, etc., are persistent and may have animal health effects on absorption through skin or organs.  I can not say definitively.  Check with http://www.cdc.gov/ for your concerns.

Lime is a mineral and should not hurt anyone.  Exception is the dust which may harm lungs.  Once wet, it should not travel.  I question the need for lime in your location.  Your soil should be pH neutral because of the parent rock in your area.

Consider that your goal is a lawn with grass in it.  A one time application of a chemical to regain control can be a useful tool.  It may not produce a perfect result, but will aid in renovation.  You may consider using a broad spectrum hormone type, like Roundup or similar to remove everything and start over again, reseeding over the dead weeds.  Using them as a mulch cover is easier than plowing, grading, and using straw to cover seed.  Consider aerating with anything you do.

This last strategy may be used next spring.  It is, probably, too late this fall to get a stand before cold weather.  Drought may impede good growth in spring, however.

With a hormone type, lawn should be safe for your dog after drying.  Use of others may require walking dog elsewhere for a day or so.  I use the chemical smell as an indicator for use.  Use CDC.org for your questions on safety.

Best wishes.