There was a time when I would race outside with lawn fertilizer in early spring even before the snow was completely melted. It seemed really important to get the grass green, and quickly. But that was before I understood how lawn grasses grow, and what they really need to do in early spring. Those early spring feedings were working against the lawn’s more informed instinct to grow roots before blades, and I was setting the agenda for a stressed-out lawn when summer drought hits.
Grass plants naturally shed about half of their root system over winter. Their first job in spring is to grow new feeder roots for the coming season, and the grass plants will set about doing this on their own, just as frost leaves the ground in earliest spring. However, when nitrogen fertilizer is applied too early in the spring, grass plants will stop root growth and put energy into blade production. The result is an early green lawn, but with shallow roots that can’t reach adequate ground moisture in a period of heat and drought. In this scenario, it’s no surprise that lawns begin to thin out and develop bald patches. These lawns don’t have the resilience and root depth to go dormant, and then green up when moisture returns.
Now I know to hold off until May for the first lawn fertilizer application. The lawn will have adequate time to grow roots all through April, and by May be strongly rooted and better able to support fresh blade growth.