Spring lawn care is useful for maintaining a healthy and vibrant stand of turf throughout the year. However, timing and proper techniques are essential to avoid common mistakes. Patience is an important word when it comes to spring lawn care. After being stuck indoors all winter, Illinoisans are eager to start lawn care at the first sign of green. However, applying fertilizer too early is a common sight on many Illinois lawns.
Late last fall, cool-season grass was passing from active green growth to dormancy for the winter. In doing so, the turfgrass was storing a lot of energy in preparation for spring. Stored energy is needed to resume the lawn’s growth when winter ends so the lawn can begin to grow vigorously and build a resilient root system for the hot, dry summer. All that stored-up energy is why we mow so much in the spring — sometimes more than once a week.
When lawn fertilizers appear on garden center shelves in mid-March, it seems logical to assume it is time to feed our lawn. Contrary to how we refer to fertilizer as “plant food,” fertilizers do not provide energy.
Plants get their food from photosynthesis, not fertilizer. Applying fertilizer to the lawn is like giving plants vitamins, which trigger a growth response. When applying nitrogen to a lawn, that growth response is to grow more leaf blades, which use up the plant’s energy.
More leaves mean a greener and lusher lawn; this is true. An early fertilized springtime lawn will be practically glowing; however, these are short-term gains and mean lots of extra mowing. The goal of the cool-season lawn is to photosynthesize and begin to develop a root system that will help the plant survive the hot, dry summer months ahead. Because lawn fertilizer triggers a vegetative growth response, this increase in springtime leaf growth sacrifices energy that would have gone to root development.
For most spring fertilizer applications, the goal is not to wake up the lawn from winter but to give it a boost after it finishes its normal vigorous spring growth. The exact timing for spring fertilizer application varies based on weather patterns, but typically it’s late April to early May for southern Illinois, early to mid-May in central Illinois, and mid- to late May in northern Illinois. A good gauge for spring fertilizer application is when you start to see the grass begin to slow down from initial spring growth.
If you fertilize your lawn only once a year, spring is not the recommended time to apply it. Instead, it is suggested to apply it in the late summer to early fall. This application window helps cool-season Illinois lawns recover from hot, dry summer months.
Crabgrass preventer with fertilizer (weed & feed), contains herbicide and fertilizer and is an example of a convenience product that sacrifices the ideal timing of one product over another. Crabgrass germinates when soil temperatures reach 55 degrees Fahrenheit for five days. Soil typically reaches this threshold early to mid-April for central Illinois, which is too early for fertilizer.
The allure of spreading lawn fertilizer in early spring is tempting; however, it’s crucial to exercise patience and apply fertilizers at the right time to ensure long-term turf health and vitality. By understanding the needs of your cool-season lawn and timing your fertilizer applications appropriately, you can promote strong root development and prepare your lawn to withstand the challenges of the hot, dry summer months. For more tips, visit the Illinois Extension’s website at go.Illinois.edu/lawns.
