Mowing and fertilizing on the same day is possible, but the sequence and timing depend on the type of fertilizer used. This choice ultimately affects the product’s effectiveness and the health of the turf. Proper preparation of the grass blades and sufficient waiting time after application are necessary to ensure the lawn receives the full benefit of the nutrients. Understanding the different mechanisms of granular and liquid applications helps determine the most effective approach.
Timing When Using Granular Fertilizer
When applying granular fertilizer, always mow first. The solid pellets must fall through the grass canopy and reach the soil surface to be dissolved by water and absorbed by the roots. Taller grass blades obstruct the movement of the granules, causing uneven distribution, patchy growth, and wasted product. Mowing first reduces this physical barrier, allowing the fertilizer to contact the soil directly. If you use a bagger, removing the clippings ensures the granules are not trapped in debris or accidentally removed.
Applying granular fertilizer after mowing is acceptable for a same-day task, but mowing after application is strongly discouraged. Mowing immediately after spreading can disturb the distribution of the pellets, especially if the product is bagged, as the mower blades could pick up undissolved granules. For maximum effectiveness, the lawn should not be mowed for at least 24 to 48 hours after application, allowing time for the granules to be watered in and begin dissolving into the soil.
Timing When Using Liquid Fertilizer
Liquid fertilizer application also requires mowing before application, though for different reasons. Liquid fertilizers are sprayed directly onto the grass blades, where nutrients are absorbed primarily through the leaves. Mowing beforehand exposes fresh leaf surfaces, which are better able to absorb the nutrient solution.
Cutting the grass to a uniform height ensures the liquid product is sprayed evenly. Applying liquid fertilizer to overly long or stressed grass can increase the risk of chemical burn, as the concentrated solution may not distribute properly. It is advisable to wait a few hours after mowing before spraying to allow the grass to recover from the mechanical stress of cutting.
Unlike granular products, the waiting period after liquid application is often shorter, but still necessary to prevent nutrient loss. The liquid needs time to dry completely and be fully absorbed by the leaf tissue, which typically takes a minimum of two to four hours. Mowing before this absorption window is complete would cut off the treated portion of the grass blade, removing the applied nutrients.
Essential Steps Immediately Following Application
After application, the most important step for granular fertilizer is to water the lawn immediately or within 24 hours. This watering dissolves the pellets, washing the nutrients into the soil where the roots can access them. For liquid fertilizers, the initial watering is typically delayed until the spray has completely dried on the leaves to ensure foliar absorption.
Proper watering helps prevent fertilizer burn, which occurs when high concentrations of soluble salts remain on the leaf tissue and draw moisture out of the plant cells. It is also important to clean up any fertilizer that has landed on hard surfaces, such as sidewalks or driveways, before watering. Granular fertilizer left on concrete can cause permanent staining or enter storm drains, contributing to nutrient runoff.