Fertilization involves adding necessary nutrients like nitrogen, phosphorus, and potassium to the soil to maintain a vibrant lawn. Proper preparation and timing are paramount to ensure grass roots efficiently absorb these elements and avoid potential turf damage. The sequence of lawn care activities directly impacts the effectiveness of the fertilizer application. A well-prepared lawn maximizes nutrient uptake, leading to uniform growth and a healthier, denser turf.
The Necessity of Mowing Before Fertilizing
Yes, you should cut your grass before fertilizing. The primary reason is to ensure the fertilizer granules reach the soil surface, where the grass roots can absorb the nutrients. If the blades are too long, the fertilizer sits on the leaves instead of penetrating the thatch layer and reaching the ground.
Allowing fertilizer to rest on the blades significantly increases the risk of foliar burn, commonly known as nitrogen burn. Fertilizer salts draw moisture out of the grass, causing the blades to turn yellow or brown. Mowing removes this physical barrier and helps prevent this dehydration effect.
A shorter lawn also allows for a more uniform spread of the product, which is crucial for achieving consistent color and density. Long grass can interfere with the spreader or cause granules to clump, resulting in uneven application and patchy growth. Mowing creates a clean, consistent surface that promotes even distribution and maximizes effectiveness.
Optimal Grass Conditions for Absorption
Waiting Period
After mowing, the lawn needs a brief recovery period to reduce overall plant stress before fertilizer application. It is recommended to wait at least 24 to 48 hours after cutting before spreading any product. This short delay allows the grass blades, which are temporarily weakened at the cut point, to heal and become less susceptible to potential fertilizer burn.
Optimal Height
The height of the grass after mowing is an important factor for successful fertilization. Follow the “one-third rule,” meaning you should never remove more than one-third of the blade length in a single session. Maintaining a post-mow height of approximately three inches or slightly higher is beneficial, as taller grass supports deeper root growth and better nutrient uptake.
Application Conditions
The lawn should be dry at the time of application, even if the soil is slightly damp. Applying granular fertilizer to wet grass causes the granules to stick directly to the moist blades, preventing them from falling to the soil. This sticking increases the likelihood of uneven distribution and causing spot burning on the leaf tissue. Applying fertilizer during the cooler parts of the day, such as early morning or late afternoon, is best to minimize stress.
Immediate Steps Following Fertilizer Application
Watering In
Immediately following the application of granular fertilizer, water the lawn thoroughly. Watering is necessary to wash the fertilizer off the grass blades and down into the soil, where the roots can absorb the nutrients. This action is essential for activating the fertilizer and preventing the concentrated mineral salts from causing burn damage.
The goal of this initial watering is to moisten the top quarter- to half-inch of the soil without causing runoff or puddling. This typically requires running a sprinkler for about 15 to 30 minutes, which helps dissolve the granules. This moisture moves the fertilizer to the root zone, ensuring the plant can immediately begin processing the compounds.
Post-Application Mowing Delay
After the fertilizer has been applied and watered in, the lawn should not be mowed again for a short period. It is best to wait approximately one to three days before the next cut. This waiting period allows the grass sufficient time to absorb the nutrients and prevents the mower from scattering any remaining fertilizer particles.