We use gluten meal liquid for control of crabgrass. Crabgrass germinates in early spring so this product must go down early as it interferes with root development of crabgrass. The product should be used consistently every year for best results. The efficacy rate improves each year about 10% if it is used annually. Aeration with gluten meal will give best results. Crabgrass is a thick bladed grass which usually becomes visible in early July but can be seen as early as May if spring comes early. As it grows out from its centre, crabgrass stays flat to the ground; it resembles a crab (thus crabgrass). It begins to choke out the desirable grasses under it. It is an annual grass, meaning it grows from seeds every year. When crabgrass dies off around October, it leaves dead areas which normally need to be repaired in the fall or following spring. Each crabgrass plant can have over 1 million seeds on it which means more crabgrass in following years. Crabgrass usually inhabits weak or bare areas, or areas where there is heat retention such as along driveways, curbs, roadways and walkways. Keeping the lawn thick and healthy and using crabgrass control every year is the best way to prevent crabgrass.
This image shows a lot of crabgrass coming up in an area where damage had occurred from the homeowner applying a non selective product for weeds. The result was that they killed off complete areas of their lawn and they created a whole new problem.