Late Winter Through May 15th, this is the second best time http://topdatingsitesreview.com of the year to plant grass.

March Through April 15th. Crabgrass is an annual grassy weed tat sprouts each year from seed in the soil. Best control comes from preventing those seeds from germinating. Only Tupersan crabgrass control can be applied to newly seeded areas.

Around mid June. Broadleaf weeds which come up from seeds or roots in the soil can be controlled now. The herbicides used are leaf absorbed, thus the need to await active growth.

Can I Fertilize at half-rate? Yes, Cosmetic fertilization can be applied at half-rat, using slow release nitrogen or organic fertilizer

Around late summer. 

Fall is the best time to fertilize cool season grasses. Fertilizing stimulates growth of deeper examples of introductions to research papers roots which will help the grass to survive possible drought in the summer

Yes, Last fertilizer application for the season will prepare the lawn for the winter.