Fertilizing new lawn seeds

Asked April 8, 2019, 9:05 AM EDT


I just seeded bare spots and over-seeded the rest of my lawn . The entire lawn was treated by a lawn maintenance company 2 weeks ago with a fertilizer (17-0-5) and weed control (broadleaf and pre-NPK emergent crab grass).
Do I need to use some kind of starter fertilizer for new seeds? If so, what should be the NPK ratio -and when should I apply it?

Thank you in advance for your help.

Montgomery County Maryland

1 Response

If a crabgrass preemergent was applied to the lawn, then the grass seed will not germinate. The preemergent inhibits germination of the seed. Look at the active ingredient and follow label directions. Take a look at our website on crabgrass premergent. You will have to overseed in the early fall. Here is more information on lawn care http://extension.umd.edu/hgic/topics/crabgrass

Also, If a preemeregent is applied in the spring, we recommend to look for products with no fertilizer. Fall fertilization is recommended. Take a look at the U of MD fertilization schedule. http://extension.umd.edu/hgic/topics/lawn-fertilizing
If your soil has not been tested in the last several years, results give pH and nutrient deficiences http://extension.umd.edu/hgic/topics/soil-testing

A starter fertilizer should only be applied if you are starting a new lawn and your soil test results indicate a deficiency. A fertilizer was applied two weeks ago by your lawn care company.
There is a new fertilizer law you should be aware of. This limits the amount of nitrogen and phosphorus that can be applied to lawns due to a negative impact on water quality in rivers, streams, and the Bay.
Lawn maintenance fertilizers have zero phosphorus in them and contain at least 20% slow-release nitrogen. Specialty products containing phosphorus are still available and may be used when a soil test indicates the need for phosphorus.