submitted When forsythia show those bright yellow blooms, that indicates to get busy applying pre-emergence weed control (crabgrass preventer) to lawns. Beth Wilson Pulaski County Extension Agent for Horticulture It's turf season! Lawnmowers will soon be cranked up in Pulaski County. Mowing is something that shouldn't be taken lightly as it can really affect disease management and weed control. In addition, there are some other jobs to be done in the spring. Spring is NOT the time for fertilizing your tall fescue lawn. To repeat, spring is NOT the time to fertilize your tall fescue lawn. Applying nitrogen fertilizer causes grass to grow so much that you have to mow more often, it many times fertilizes weeds that are already out there, and it predisposes tall fescue to brown patch disease.