Certified GKH Gardening Expert
I would wait until later in the spring to fertilize, to let the seeded areas get a good hold without possibly burning the new roots of the newly growing grass. In late spring, use a fertilizer that is higher in nitrogen (the first number in the N-P-K number). Growmore has several different fertilizers, so it would depend on which you plan on using. If it has a higher nitrogen, then it will work.