By Tom Kalb, Horticulturist

NDSU Extension

Do you want to have a great lawn? If yes, it is time to get busy.  

Now is the best time of the year to fertilize your lawn. The secret to a great lawn is a strong root system, and lawns develop most of their roots in the fall.  

Nitrogen is most important for turf growth. Look for a fertilizer that has over 20% nitrogen. Select a fertilizer with slow-release nitrogen. This will gradually feed the grass until the ground freezes.

Early September is the optimal time for fertilizing.

Do you have bare spots in your lawn? Now is the best time to sow grass. The ground is warm and the seeds will germinate quickly.

Choose a quality seed mix that contains a blend of grasses. Most seed mixes include varieties of Kentucky bluegrass, fine fescues, and perennial ryegrass. Each of these grasses have strengths and weaknesses that complement each other.

The strengths of Kentucky bluegrass are that it is hardy and will develop a thick, attractive turf. The weaknesses of Kentucky bluegrass are that it cannot tolerate shade or salty soil.

This is where the fine fescues may help. They tolerate shade and salt much better. Fine fescues are a group of grasses that include chewings red, creeping red and hard fescues.

The problem with bluegrass and the fine fescues is that they may take two to three weeks to germinate. This is why we include perennial ryegrass in the mix. It germinates within five days and will stabilize the soil until the other grasses germinate.   

Sow your seed by September 15 to make sure it gets established before winter arrives.

If you prefer sodding over sowing, now is the best time to lay sod. Sod grows actively in the fall and will quickly knit into the ground.

Do you have weeds in your lawn? Fall is the best time to kill perennial weeds such as dandelion, creeping Charlie, thistle and clover.

The key to killing weeds is to get the herbicide down into their roots. As days get shorter, weeds will begin channeling their nutrients down into their roots to prepare for winter. This is great, because a herbicide sprayed on a weed in fall will naturally be channeled down into the weed’s root system, killing the entire plant.

Mid-to-late September is the optimal time to control weeds.

Now is the best time to aerate, too. Aerated lawns will respond with vigorous root growth until the ground freezes. Many gardeners overseed immediately after aeration. If overseeding, do this by mid-September.

Fall is the best season to improve your lawn. A little attention to your lawn now can lead to a thick, beautiful lawn next spring.

For more information about gardening, contact your local NDSU Extension agent. Find the Extension office for your county at www.ndsu.edu/agriculture/extension/county-extension-offices.

NDSU Agriculture Communication – August 28, 2025

Source: Tom Kalb, 701-877-2585, tom.kalb@ndsu.edu

Editor: Kelli Anderson, 701-231-6136, kelli.c.anderson@ndsu.edu