GARDENING AND PESTICIDES :: FERTILIZERS/ALGA BLOOMS

Fertilizers and Arlington Waterways

During Texas’ hot summer months, many of our area waterways have an excessive growth of algae (small aquatic plants). Fertilizers and other nutrients can trigger this growth. Algae can cause water in our lakes, ponds and rivers to turn green, brown or black in color, have an unpleasant odor, and become a nuisance. In extreme cases, excessive algal growth may contribute to the death of fish and other aquatic organisms.

Causes of Algal Blooms

Algae are aquatic plants that naturally occur in ponded or slowly moving water. Blooms, excessive numbers of algae, occur when a nutrient, in a low amount is added to the aquatic system. This extra amount of nutrient causes the algae to undergo a "population explosion." 

Where do these nutrients come from? Typically we introduce them by overly or improperly applying fertilizers to our lawns. Rainfall runoff and irrigation water can carry soil, leaves, and other organic wastes into our creeks and ponds which also provide nutrients. 

Phosphorus, a component of fertilizer, is believed to be one of the prime causes of algal blooms. Fertilizer constituents are specified by three numbers. Phosphorus is the middle number.

Usually, lawns with sandy loam soil require a small amount of phosphorus. Black clay soils usually do not need any phosphorus.

Help Reduce the Problem

• Test your yard soil to determine the type of fertilizer needed. Sampling kits are available through the Texas Agricultural Extension Service, 817-884-1946. The chemical analysis will cost.
   

• Do not apply fertilizers or pesticides when rain is predicted. Water your lawn to move the fertilizer into the  soil.
    

• When applying fertilizers, sweep up any excess that falls on sidewalks and streets and place it on the lawn.
   

• If you have a small private pond or lake, you may want to consider an aeration system to help combat the algal problem.