Sandburs grow best in poor soils and usually sandy soils. To eliminate them the soil needs to be improved by adding adequate amounts of organic matter which will then allow grass to grow in. Spraying manure, or compost, tea onto soils lacking adequate amounts of organic matter will do very little since the micro organisms the tea provides will have little to nothing to eat once out of the brewing medium.

Your Texas A & M Cooperative Extension Service has an article on controlling sandburs that suggests using various plant poisons while my experience is that simply getting the amount of organic matter in the soil up to levels that are adequate is more effective and will encourage grass to grow as well.

kimmq is kimmsr