Additional Fertilizing Tips 1. If you have a thatch problem, you're either fertilizing too much or using the wrong type of fertilizer. Use a fertilizer that feeds the soil as well as the plant. Experts recommend the use of natural fertilizers that contain controlled-release nitrogen and micronutrients that enhance humus development. The most important feeding is in late fall, just before the grass goes dormant.
Roots are busy processing and storing the materials necessary for their next growth cycle.
A spring feeding helps, but is much less effective. As with water, too much fertilizer is worse than too little. Burn out for one. Yet even a lawn that looks healthy can be ailing. If you've over-stimulated growth through too much fertilizer, you may have a thatch problem.