spring overseeding

This is the second year in our new house in the northeast region. The builder didn't do a good job of hydroseeding the lawn in the spring of

2004. As a result there were lots of bald patches and during summer and fall I saw crab grass taking over everywhere. I tried to overseed but it didn't take root. Ony crabgrass grew in those areas. I applied a fall fertilizer in november. It is now spring and I see nice green color in several areas but I also see all dead crab grass in sevral areas mixed in with green grass. I would like to overseed properly this year (what seed mixture do I use for connecticut and how should I do it so it takes root?) I also would like to apply scot turf builder with crab grass control but I am not sure about timing of these two as I am afraid one might kill the other. Any help is appreciated.

Immediately apply a pre-emergence crabgrass preventer. One with fertilizer should be fine, but follow the directions carefully. That will last about 3 months and prevent seed from germinating. Do not allow the crabgrass to tassle. You can use a spot weed treatment (such as Weed-B-Gone or Specrtride) now that weeds are actively growing but this won't stop the crabgrass. Test the pH and apply lime only if needed. It would be good to test the soil for nutrients and add whatever is needed. After three months of the pre-emergence with fertilizer you can apply a turf builder or processed organic fertilizer (Milorganite, pelletized chicken manure, composted mushroom compost, etc). Prepare the site for overseeding in the fall by refraining from use of chemicals for at least 2 months, dethatching if necessary, aerating if needed. Use high quality seed. Ask several nurseries about the best grass lawn for your area. On the overseeding day use a starter fertilizer, distribute the seed, protect with straw and keep moist for 3 weeks. Maybe Kentucky bluegrass mix will grow well in your area--a fine, soft, hardy barefoot grass. Be generous with the seed application and fill in any bare soil especially in sunny locations--this will help shade out the crabgrass problem. Crabgrass seed can remain dormant for 20 years. The fertilizer you applied in November was a very good thing.