I remember you wrote a column last year about the best time to put down fertilizer with crabgrass preventer. Something about between the forsythia blooms and ? Thank you . I love your column. -- Bob K.
The time to put down pre-emergent crabgrass like corn gluten meal, Preen, etc., is during a window that begins when the forsythia begins to bloom on your block and ends when the lilacs fade. That's usually sometime around the end of April, but let the plants, not the calender guide you. Weather variations and microclimates created by structures, the amount of grass and trees vs. brick and mortar on the block, etc., all can prompt or delay plant dormancy and blooming, and those same weather indicators are the ones that will make crabgrass control effective.
Fertilizer is another story, which is why I don't recommend those combination products. The most beneficial time to fertilize the lawn is around Memorial Day (then again around July 4 and one last time around Labor Day). It's illegal to fertilize lawns before April 1 in Nassau and Suffolk.