My lawn is very thin this fall, probably due to the excessive rain and little sunshine. I am considering overseeding it. Would I be able to successfully overseed today and still apply the usual high nitrogen fall fertilizer in a couple of weeks or would the nitrogen kill any new seedlings.
The best time to seed is late August to mid October. It is getting late and should be done as soon as possible. You are gambling with Mother Nature but we may experience some warm temperatures. Test your soil if you have not done so the last several years. Results give pH, liming, and fertilization recommendations. http://extension.umd.edu/hgic/topics/soil-testing
Select recommended turf grass cultivars. For full sun to part shade - turf type tall fescue. For shady conditions, a hard fescue. See more http://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/hgic/Non_hgic_pubs/TT-77%20Rec...
Provide good seed to soil contact for germination. For small areas you can use a hard rake. For large lawns you may need to core aerate. You can fertilize at the same time or by November 15th according to the MD Fertilizer law. Lawn fertilizers now sold in the state are formulated to comply with the lawn fertilizer law. Lawn maintenance fertilizers have zero phosphorus in them and contain at least 20% slow-release nitrogen. See more lawn care information on our website regarding seeding, fertilizing, and care after seeding. http://extension.umd.edu/hgic/topics/lawn-care