Plus weather is a big factor. I've seen grass areas with no crabgrass one year and lots another. The right height for your grass helps to shade weeds out of existence. By mowing both often and regular, you remove the flowing seed parts of many weeds thus making it harder for them to seed their next crop. A weakened turf grass allows for the weeds to grow.
Weeds love poor, under-fertilized soils.
While Turfgrasses require a certain amount of nutrients for best growth. All rights reserved.