Ideally, you'll want to mow and rake before fertilizing, so that excess lawn waste is removed and the fertilizer will have an easier time reaching the soil.
When fertilizing a lawn, it is best to apply fertilizer after the lawn has been mowed so it has a few days to absorb the fertilizer.
Lawn fertilising tips
Before fertilising, rake the lawn to remove leaves and other debris. Allow at least two days after mowing before fertilising. Wait about a week after feeding before you mow - and leave the catcher off the first time (the fertiliser could all end up in it if it's left on!)
Nitrogen, phosphorus, and potassium take time to absorb into your soil. Doing anything too drastic on your lawn, such as cutting your grass, will disrupt this process. We always suggest to our clients that they wait 24 to 48 hours before mowing their lawn after fertilization.
The best time to make late fall applications of lawn fertilizer is typically in November or the very beginning of December when the grass stops actively growing or has slowed down to the point of not needing to be mowed.
If done too early you could be inviting damage from the winter weather, such as snow mold. The best time to fertilize can depend on the climate, but typically September and October are usually the best months to apply fall fertilizer.
Fall Fertilizer Timing
For the majority of cool-season lawn owners, apply fertilizer anywhere from September through early November. The further north you garden, the sooner you'll feed your lawn. Fine-tune the timing for your locale by talking with your local extension service or garden center.
You can usually apply most non-liquid granular fertilizers to wet grass, but not saturated ground. If there are ponds or heavy rain, it's best to wait until the ground processes the water before applying any type of fertilizer. If there's light rain, it's okay to spread dry granular fertilizer.
Although there are reservations to this, adding fertilizer to your wet grass is a great way to give it a boost of nutrients. When you add fertilizer to wet grass, the roots absorb nutrients more efficiently. This is because water helps break down nutrients, making them more available for plants.
Watering after fertilizing washes the fertilizer off of the grass blades and into the soil, where it can get to work nourishing your lawn. It's also important because if fertilizer sits too long without being watered in, it can burn the grass.
Ideal Time to Fertilize
Applying fertilizer (and water) in the afternoon will cause the moisture in the soil that is preventing the lawn from burning to evaporate as the sun beats down on the lawn. It's also important for grass to dry out slightly before the nighttime temperatures.
However, most professional gardeners would agree that between 8 AM and 10 AM is the best time of day to cut your grass. The reason for that is that lawns need time to heal before evening. Grass needs the benefit of the day to dry and heal before dusk settles.
When is the best time to fertilize a lawn – before or after a rain? Too much rain could wash away the fertilizer before it has a chance to soak into the soil, so plan to fertilize several days before a heavy rain arrives or several days later.
The standard recommended time you should wait is between 24 to 48 hours (again, check the specific fertilizer in question for further guidance). Most granular fertilizers also recommend watering the grass to help it absorb the nutrients better, so if you do so, you also need to wait for the grass to be dry.
Generally speaking, you should fertilize your lawn at least twice a year to ensure good overall health and keep your grass looking its greenest. But if you fertilize at the wrong time or over-treat your lawn, you could encourage weed growth, or possibly burn the grass.
How Long Does Lawn Fertilizer Take To Work? Fast-release synthetic lawn fertilizers work within 24 to 48 hours after application. Slow-release fertilizers work more slowly, but they are less risky to use. Synthetic slow-release products work in 2 to 5 days, while organic slow-release versions work in 2 to 6 weeks.
At Master Lawn, we typically say to wait 24 hours before watering your lawn after fertilizing. But it is important to make sure that it does receive a good watering session soon after that 24 hour waiting period. Watering helps the fertilizer to activate and to break down and begin feeding nutrients to the lawn.
Most people understand that fertilization helps to thicken a lawn. However, you want to make sure that you are using the best fertilizer to thicken grass if you truly want to get the best results.
Rain, or watering-in too early, is fine for the grass, but it washes the product off the weed leaves, so the weed killer can't do its job. To be safe, it's best to apply the fertilizer when the weather is sure to be dry for a day or more. Then, simply water-in with sprinklers after 24 hours.
You should fertilize your lawn a day or so after a light rain or using a sprinkler. This prevents the application from being washed away. The moisture gets your soil damp and ready to receive nutrients. Do not apply fertilizer before or after heavy rains.
“I don't recommend fertilizing before or after a heavy rain because the fertilizer can be leached out of the soil or washed away before it can be consumed by the root zone,” Clarke says. Instead, the best time to fertilize the lawn is right before a light to moderate rainfall.
If fast results are desired, lightly water the product in after application; however, watering-in is not required.
When To Fertilizer Your Lawn in the Fall. The best time to apply your last fertilizer application is between August 15 and October 1. Ideally, your last lawn feeding should take place six to eight weeks before the average first frost in your area.
The ideal temperature to fertilize your lawn is 50-70 degrees Fahrenheit. Any lower than this, your lawn will struggle to maintain nutrients.
Apply fall lawn fertilizer once between August and November, right before winter hits, 6 to 8 weeks after the summer feeding.