Pre-emergent and fertilizer
This year was the first Spring season that I applied pre-emergent on my lawn (about two weeks ago). The lawn was then aerated (Fall and Spring). Should I be applying fertilizer also? If so, how long do I wait (after the pre-emergent)? Thank you.
Jefferson County Colorado
Assuming you have a cool-season grass lawn like KY bluegrass.
Yes, apply a fertilizer to the lawn mid-April to mid-May IF none was applied last fall (Oct).
Try not to apply an excessive amount of fertilizer in spring, as that can lead to certain diseases and heat/drought injury in summer.
Fertilizer application to lawns is independent of (not affected by) when a pre-emergent was applied.
See also: http://www.ext.colostate.edu/pubs/Garden/07202.html