GARNETT — The city of Garnett has approved a six-month extension for Astro Manufacturing of Garnett from the requirements of a state economic development grant. Under terms of the grant, Astro must add 20 new employees but the company had to lay off some of those employees last year because of the economy. Astro Manufacturing makes truck toppers and accessories. The company’s market relies heavily on new truck sales, and demand for pickups has dried up. Because the grant was funneled through the city, the city commission had to approve the six-month extension.