Fertilizers supply your grass with necessary nitrogen, which helps it remain green, along with trace amounts of other needed nutrients. It's usually applied in spring, early summer and fall when mowing is a regular chore. Mowing at the right time ensures the fertilizer performs its job so the grass can look its best.
Patience Pays Off
Your lawnmower, especially if it's equipped with a grass catcher, acts like a vacuum and sucks up the fertilizer before it can dissolve into the soil if you mow too soon. Waiting 24 to 48 hours allows most of the nutrients to soak into the soil. You must wait two to four hours, or until the grass is dry, if you use a liquid or spray-on fertilizer. It's best to wait even if you leave grass clippings on the lawn, because mowing too soon will still disturb the fertilizer so it's no longer evenly applied.
Mowing before you fertilize removes excessive growth and debris, like fallen leaves, so the fertilizer can reach the soil more quickly. Lawn fertilizers are usually applied to dry grass, unless the fertilizer also contains an herbicide. Herbicide and fertilizer mixtures are applied after a light watering so the herbicide can stick to plant leaves. Water after application so the nutrients soak into the soil if you are using plain fertilizer, then mow a few days later when the grass is dry.