Ask the Expert: 4 Reasons Why You Should Focus on Fall Fertilization, Plus Recommendations for Application

Now is peak time for fall fertilization with cool-season turfgrass and for decades, lawn care managers have prescribed fall fertilization. As always, the inevitable question of “why are you fertilizing my lawn with only a few weeks left in the growing season?” arises. Fortunately, scientific research has be able to provide answers beyond, “because it works.” That’s why we’ve connected with Jeffrey Thrasher, Central’s Liquid Chemicals and Fertilizer Products Manager, and asked him to share why fall is the best time to fertilize cool-season grass.

From Jeffrey:

1. Summer Stress Recovery

Summer is the most difficult time for turf. Fending off drought, heat and disease pressure can leave turf in a weakened state. Giving you grass a late season nutrient boost will help speed recovery.

2. Carbohydrate Storage

Carbohydrates are the ‘energy’ source for plant growth. By the end of the summer turf grass can have depleted its energy reserves to stay alive and healthy. Fall is the time of year the plant can replenish carbohydrates, storing them in stems, rhizomes and stolons. The plant’s restored energy resource will enhance resistance to winter injury and spring disease pressures and provide the energy reserves needed for spring green-up. Fall fertilization promotes this essential carbohydrate storage process.

3. Spring Green-Up and Winter Color

As turf grass that goes into winter actively storing carbohydrates is going effectively green-up in the spring. The up-front nitrogen in your fall application needed for promoting carbohydrate storage and root growth will also deepen turfs green color over the winter.

4. Enhanced Root Growth

If you were to look at a diagram showing turf growth above and below the ground through the entire growing season it would look as follows; heavy top growth and some root growth in the spring, some top growth and little root growth to root loss in the summer and heavy root growth and some top growth in the fall. In other words, there is a lot of growth going on in the fall even though it does not appear that way from your front porch. The grass needs a healthy dose of nutrients to enhance this essential root growing season.

Recommendations for Application:

When to Apply / How Much Apply

For managers with five fertilization visits a year the fall fertilization program begins with a late summer/early September application followed by the late Fall application. The late fall application should be timed for the very end of the top growing season; the second half of October in northern cool season grass areas to the end of November in transition zones. The timing of the application is intended to get nutrients into the plant while it is still actively growing roots and when, at the same time, top growth has slowed to its end. If you are too early with this application the resulting late season top growth will have less cold tolerance and be vulnerable to diseases such as snow mold.

For the combined late summer/early fall application and the late fall application 1.5 lbs. – 2 lbs. of nitrogen should be applied. In other words, up to half of your annual nitrogen application. We are encouraging surge growth, only at this time of year it is intended to occur below ground.

What Fertilizer to Apply

Meeting the late fall treatment nitrogen requirement calls for an NPK ratio of approximately 4-0-1. Hudson Valley Naturals ‘Jackpot Green’ with a 21-0-5 analysis is well suited to this application. It provides added up front nitrogen release and slow release nutrients in organic matter that will still be available as the grass wakes up in the spring. The organic matter also provides a host of additional nutrients and biostimulants, stimulants and carbon energy for microbes.

It is well known that microbes decompose organic matter to cycle nutrients into plant availability. What’s less well known is how they boost the presence of the most important element for plant growth, oxygen. One way they add oxygen is by emitting a number of compounds that have a ‘cementing’ effect on soil aggregates, opening pathways for oxygen diffusion. This dynamic is one more example of the intricate relationship between soil microbes and plants and one more reason for using fertilizers with organic matter.

Applying a late-season fertilizer has been recommended since before we knew all the good reasons why. Forward thinking turf managers include it in their best practice planning.

Planning and Strategic Purchasing

Now that you have a plan for fall fertilization, have you started planning for spring? Central offers a Turf Early Order Program which helps you plan for spring. Lock in discounts for fertilizers, chemicals, and other products. This year, our industry has seen major supply-chain issues and we only expect them to continue into 2021. When you take advantage of our Turf Early Order Program, you can combat these issues and guarantee you have the product you need, when you need it. To learn more about the program and to learn about additional discounts available through manufacturers’ end-user rebates, connect with your local Central rep.

Finally, rely on the experts at Central to help you with any of your fertilization, or turf grass questions. We stay at the leading-edge of the industry. We have experts on staff at all our local branches and they’re ready to help you grow!

About Jeffrey Thrasher

Jeffrey Thrasher is a licensed Arborist with more than three decades of experience in the Green Industry. Jeffrey built a successful tree, lawn and landscape company in Westchester County, NY and Fairfield County, CT. After selling his business, he began work with fertilizer manufacturers to establish distribution nationally. This extensive hands-on knowledge and background has given Jeffrey the necessary tools and background to troubleshoot and solve the most difficult tree and ornamental issues. Jeffrey is an excellent resource to help you finding the right product and solution for your customers.