I would apply lyme in the spring, but first I would go and get a bag of Scotts weed killer and fertilizer, use a 15-20-15 blend and apply at a setting of 4.5 on your broadcast style spreader, apply just after a rain when the ground is wet to help the granuals stick to the grass. I would also raise your mower hieght to about 3" to avoid cutting to deep and burning the roots with hot sun. About mid spring, I would apply some turf builder at about the same setting on your spreader. Water regularly. It may be necc to use some grub killer depending on your growing area. I like to follow up in the fall with some Round-up over the entire lawn, because by now, it looks like hell! I have chosen rubber grass and some well placed rocks to disguise my yard and have found that painted concrete will give equally good results with low maint.