A common problem in the urban landscape is dealing with unsightly algae/weed growth in small ponds. In most cases, the algae/weeds are not the heart of the problem, but a symptom of it.
There are a variety of factors that can lead to this including several that are beyond the practical control of the homeowner such as dramatic weather changes/events, improper pond construction, and fluctuating water depth. However, one key issue is something that many of us can help correct with relative ease.
Runoff of excessive fertilizer (especially phosphorus) from improperly applied lawn fertilizer is a major contributor to excessive weed and algae growth. Improper application can mean several things including:
- Fertilizing immediately before a heavy thunderstorm. If fertilizer has not had a chance to dissolve into the soil, it moves with water very freely and will follow storm runoff right into the nearest creek or pond.
- Application of un-necessary nutrients. We are fortunate in Payne County in that our soils usually contain adequate levels of most of the critical nutrients plants use, including phosphorus, the primary culprit leading to excessive algae growth. Nitrogen (and to a lesser extent, potassium) are exceptions. Growing plants use these nutrients in large quantities and regular applications are a part of a good landscape maintenance plan.
- Over application. The old saying “if a little is good, a lot must be better” does not apply in this case. Apply only what the plants can use.
- Careless application. Fertilizer on sidewalks, driveways, and other hard surfaces can be a significant contributor to this problem.
- Take a soil sample every three or four years to insure you only apply the nutrients your plants need. This $10 sample (available through the Payne County Extension Office) will pay for itself many times over in fertilizer cost savings alone, not to mention the improvements in nearby pond water quality.
- Assess the goals for your landscape. If your plants don’t need it, don’t apply it. Let’s use a bermudagrass lawn as an example. Bermuda responds very well (meaning grows fast) with regular applications of nitrogen. If your lawn sees a lot of human or pet activity, it may well need this fertilizer to maintain good turf cover. However, if it does not get much traffic, over application simply leads to more mowing than necessary.
- If you hire a professional to do your lawn care, don’t be afraid to have a conversation with management and ask what they are applying and why they are applying it. Does their plan line up with your expectations? Are they choosing product based on a soil test or is it a “one size fits all”?
Oklahoma State University, in compliance with Title VI and VII of the Civil Rights Act of 1964, Executive Order 11246 as amended, Title IX of the Education Amendments of 1972, Americans with Disabilities Act of 1990, and other federal laws and regulations, does not discriminate on the basis of race, color, national origin, gender, age, religion, disability, or status as a veteran in any of its policies