Pond weeds

Pond weeds

By BIRGITT THORNHILL

Extension Agent, Agriculture

Have you had a problem with pond weeds? Then please do not fertilize your pond. I am writing this article to contradict the article in the February issue of Cooperative Farmer on pond weed problems.

The article stated that if you fertilize your pond, it will cause a bloom of algae which will shade out weeds and they will die. This may be true, but the algae that blooms in this area cannot be eaten by fish and is considered a harder weed to control than plants that grow at the bottom of the pond. The weeds that die in turn act as a fertilizer in the spring to promote new plant growth. The “microscopic plant life” that the article speaks of is very undesirable to have in your pond.

The article goes on to state that “most pond weed problems can be handled by properly fertilizing the pond.” This may be true in the warmer southern states — South Carolina, Georgia or Florida — but not in Virginia.

The Extension Service recommends that you never fertilize your pond. If you call the office for help with this problem, the first thing we ask is: would you know where fertilization is coming from to get into your system? (I.e. pasture run off, cattle watering hole, or commercial pond fertilizers.) Chemical control is a dangerous practice that cannot be recommended by this office. Chemicals that kill nuisance waterweeds are also toxic to beneficial water plants, fish, and other forms of aquatic life, and are potentially dangerous to humans, livestock, and other mammals. This practice is not only dangerous, but is a poor way to control on a continuous basis. The problem is overfertile waters which remain untreated using this method. To control weeds, they must be removed from the aquatic system.

A publication is available at the Extension Office entitled “Controlling Aquatic Weeds and Improving Water Quality in Ponds and Lakes.” Please write or call the Extension Office at 675-3619 and we will be glad to send you a copy.