Start with a soil test, which will tell you exactly what your lawn needs to thrive. Soil tests can be provided through private and university services, and are a quick, easy and inexpensive way to dial in the right nutrients and essential elements, without wasting time and money applying unneeded or possibly even harmful amounts of fertilizer.
Keep in mind fertilizer recommendations for a new lawn generally differ from those of an established lawn. That’s because, with a new lawn, you have a chance to incorporate fertilizer into the soil before sowing seeds or laying sod. Certain areas of your yard, such as high-traffic lanes in established lawns, may also need more TLC to thrive. When in doubt, check with your local extension service agent for recommendations tailored to your property.
Most Minnesota lawns flourish with a mixture of nitrogen, phosphorus, and potassium. The percentage of these essential elements within each bag of lawn fertilizer is expressed in numbers on the bag’s label, which are called the “fertilizer grade.” Match these numbers to the requirements of your soil test. For example, soil already high in phosphorus and potassium would do well with a blend of 21-0-0 or 46-0-0, while soil with low phosphorus or potassium requires something closer to 20-5-10 or 23-0-6.
Timing is also important. For example, it’s tempting to jump-start your lawn’s look with an early spring dose of nitrogen. While this can produce a quick shot of green, the surge in top growth actually depletes the plant’s energy reserves, making the grass more susceptible to summertime stress.
Late August and September applications are the smarter play. Benefits include an extended period of autumn green; earlier spring green-up without excessive shoot growth; higher energy reserves in spring and summer; and fewer incidences of summer diseases.
Finally, when applying your fertilizer, take care to provide even coverage. Granular fertilizer is easiest for successful do-it-yourself applications. Set your spreader at half the recommended rate and apply in an overlapping parallel or crisscross pattern to avoid uneven shades of green, and ensure your lawn remains lush and healthy all season long.