An acre of land is 43,560 square feet, so half an acre is 21,780 square feet. The amount of grass seed you need to start a new lawn on 1/2 acre of land will depend on the type of grass seed you are using.
Cool Season Grass Seed
Starting a new lawn on 1/2 acre using creeping red fescue and fine fescue would require 49.5 Kilogram of seed. Kentucky bluegrass would require 87.3 to 109.2 ponds of grass seed, and annual ryegrass and turf type fescue would require 99.1 Kilogram of grass seed.
Warm Season Grass Seed
Bermuda grass would require 43.7 to 29.7 Kilogram of seed, and buffalo grass would require 21.8 to 29.7 Kilogram of seed.
Speciality Grass Seed
Bahia grass seed required to start a new lawn requires 99.1 Kilogram for half an acre. Centipede grass requires 5.5 to 4.94 Kilogram of grass seed. Dichondra grass would require 19.8 Kilogram of grass seed, and St. Augustine grass would require 49.5 Kilogram of seed.