UC Healthy Lawns—Fertilizing established lawns

The UC Guide to Healthy Lawns

Fertilizing established lawns

Lawns that are discolored, slow-growing, or have invading weeds or other pest problems may not be properly fertilized. Fertilizer is important for healthy, vigorous plant growth and development. Because many of the required nutrients for turfgrass are found naturally in the soil, fertilization practices focus on the supply of three primary nutrients — nitrogen, phosphorus, and potassium. Nitrogen is the only nutrient that turfgrass needs on a regular basis. Lawns may occasionally be deficient in iron, and fertilizers containing iron may be supplemented. As nitrogen is applied, both root and shoot growth increases. If too much nitrogen is applied too frequently, shoots will continue to grow yet root growth will slow, leaving the turf vulnerable to problems.

See the following publications for more information:

"Practical Lawn Fertilization" (PDF* 680K)

Benefits of grasscycling

Grasscycling supplies about 20% of the fertilizer requirements of most grasses. Leaving your clippings on the grass after mowing is beneficial as it returns nutrients back to the soil. However it is only beneficial if you follow proper watering, mowing, and fertilizing guidelines. Avoid overfertilizing as it can cause vigorous shoot and stem growth, contributing considerably to thatch buildup.

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Follow these steps to give your lawn the nutrition it needs:

Make sure this is the right time to fertilize your turf.

Purchase fertilizer and check the label to see how much nitrogen it has in it.

Determine how much actual material you need to apply per application and how often it should be applied.
Set your spreader to the appropriate setting.
Pour the material into your spreader over a driveway or other cement area where spilled material can be swept up (pouring over a lawn where spilling may occur can lead to burn); do not let excess fertilizer be washed into storm drains.
A few days before you fertilize, deeply irrigate your lawn so that the soil is moist; the grass blades should be dry by the time you start your application.
Apply fertilizer.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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