Lawn & Fertilizer
True or False?
“More is better” when applying lawn fertilizer.
False! Over-fertilizing is a problem contributing to stormwater pollution in the Clinton River Watershed. Without realizing it, many landowners are also applying herbicides and pesticides when their lawns don’t even need them!
While applying an appropriate amount of fertilizer is usually okay, it’s important to take care when adding chemicals to your lawn so that we can keep our rivers, lakes and wildlife healthy.
Don’t Guess… Soil Test!
Don’t assume your plants need fertilizer. Perform a soil test. You’ll save money and reduce the chance of over-applying by only replacing the nutrients your soil is actually missing. Most soils in Michigan have high levels of phosphorus, making the additions of phosphorus via fertilizer unnecessary.
Fertilizing Your Lawn
The Clinton River Watershed Council is an active participant in the Healthy Lawns and Gardens Technical Advisory Committee (HLGTAC) and a supporter of its earth-friendly fertilizer program.
Use an Earth-friendly fertilizer. Earth-friendly fertilizers include products which meet these criteria:
- 50% or more of the nitrogen in slow-release form Low or no phosphorus (N to P ratio is 5:1 or greater)
- Pesticide free (no weed-and-feed)
Avoid “weed-and-feed” mixtures. These contain herbicides to control weed growth and are often applied where they aren’t needed. If healthy lawn care practices are followed, weed control shouldn’t be necessary. Combination fertilizer and weed control products oftern add unneccessary herbicides to the landscape. Herbicides may pose a threat to children, animals, plants and beneficial insects beyond the intended weeds or pests. Spot-treatment or hand-digging of weeds are better approaches for weed control.
Sweep Up Fertilizer from Paved Surfaces. Sweep fertilizer from sidewalks back onto the lawn. Fertilizer left on sidewalks and driveways can easily wash into storm drains, rivers and lakes. If possible, use a drop speader-not a rotary spreader.
Healthy Lawn Care Practices
- Aerate Your Lawn.
- Tightly packed soil restricts root growth and prevents water and fertilizer from penetrating the soil (increasing stormwater problems). Core aerators remove plugs of soil throughout the lawn. Holes give grass roots space to grow and helps prevent weed growth and thatch problems.
- Mow High/Leave Clips.
- Be sure your mower is set to three inches to help shade out unwanted weeds. Tall grass promotes root growth and shades out weeds. Sharpen your mower blade at least once a year. Let short clippings fall back into the lawn. Clippings are a source of nitrogen, so fertilizer can be reduced by 25% or more.
- Water the Lawn to Minimize Disease and Insect Pests.
- A green lawn in Michigan needs 1/2 to 1 1/2 inches of water per week, depending on the site and turf grass type. Overwatering causes more weed, disease and pest problems than underwatering. Install rain gauges and measure how much you are watering AND take control of your sprinkler system! Turn it off during adequate periods of rainfall.
- Rake Compost Into the Lawn.
- Spread 1/2 inch of compost over an established lawn. Rake into the lawn, leaving 1/2 of the grass blade exposed to sunlight and air. Compost adds microorganisms, nutrients, and organic matter to help build fertile soil.
- Leave a “No Fertilizer” Buffer Zone Near Lakes & Rivers.
- The recommended width for “no fertilizer” buffers is 10 to 25 feet, depending on the slope. Instead of turfgrass, plant native grasses or shrubs to trap pollutants and discourage Canadian geese.
How Often, How Much?
If you have fertilized in the fall, you will have a green lawn in the spring. Fall is the most important season for fertilizing. Additional fertilizer before May is rarely needed-never fertilize before the ground thaws. Never fertilize more than four times a year. Follow these guidelines (recommended by HLGTAC) for timing and frequency:
- One application per year: Fall
- Two applications per year (with clippings): Late spring and fall
- Three applications per year (sodded with clippings): Late spring, early fall and late fall
- Four applications per year (newly sodded, no clippings): Late spring, early summer, early fall, late fall
Know the size of your lawn and adjust fertilizer spreader to apply the correct amount of fertilizer.
Pointers for Pesticide Use
Correct watering, mowing and fertilizing habits can reduce many pest problems. But if you do choose to treat for insects, it is essential that you know your enemy before you apply pesticides! If possible, hand pick the little buggers off the plants and identify the pest. The important part is to identify and treat only for the pests you have, at their most vulnerable stage. A general spraying of insecticide is ineffective, costly and may do more harm than good.
Healthy Lawn Resources:
Click here to learn about for earth-friendly fertilizers & pesticides.