Can I still fertilize my grass? This has been one of the hot topics lately coming into the helpline.

This time of year, we need to be careful with fertilizer. Often we see commercials telling us that we need to “winterize” our yards so they can make it through the winter. This is not true in eastern North Carolina. If we were in the mountains or perhaps in northern Virginia, we would have cool season grasses in our lawns. Cool season grasses grow best in the fall and spring when ambient air and soil temperatures are much lower. It is for this reason that they are not recommended here in the East. When we have several days, and nights, of 90-degree-plus temperatures, cool season grasses begin to die. This leaves great big patches of dead grass throughout your lawn. Eastern NC is much better suited for warm season grasses that can withstand, and actually enjoy these temperatures.

This season, we experienced periods of drought. Due to these conditions, lawns were stressed, resulting in thin turf or dieback of whole areas. Typically, healthy turf can withstand periods of drought, especially with a little help. One of the best things you can ever do for your grass is to keep it mowed at the correct height. Most warm-season grasses like to be kept between 1 and 2 inches tall. The exception is St. Augustine grass that likes to hang out at around 3 inches tall. Try not to mow more than a third of the overall height in one mowing (height is measured from the soil surface to the top of the grass blade). Keeping the grass at the right height helps with root growth and minimizes stress levels. One thing most warm season grasses cannot stand is shade. If you let your grass continually get too tall, it will shade itself out. The lower blades of the grass will die out, forcing it to stretch towards the sun to compete for sunlight with its neighbor. This results in major stress on the grass and makes it look as though you’ve scalped your yard every time you mow. If you have this problem, bite the bullet and mow the grass low over the course of two mowings, about three days apart. It will come back so much better.

This season, due to drought conditions, many folks did not fertilize their grass. This is a good thing because during a drought, grass shuts down, essentially going dormant, conserving energy to keep the crown of the plant alive. This is a mechanism by which most warm-season turf can sustain itself during longer periods of drought. When it begins to rain again, the plants will green-up all over again. This takes a great amount of energy, however, and requires us to fertilize once they have re-emerged. Each of the warm-season grasses has a different fertilizer requirement. Bermuda grass requires the most fertilizer and centipede grass, the least. Often we can get away with not fertilizing centipede at all!

Going into the fall, however, is not a good time to fertilize our warm-season grasses, especially with nitrogen-containing fertilizer. I mentioned earlier that all warm-season grasses do not like shade. As soon as the days begin to get shorter, these grasses begin to go through the process of getting ready for dormancy. If you think about it, look at your son or daughter’s soccer or football field this September. Once the days get a little shorter, most Bermuda grass will begin to go dormant. If the field isn’t over-seeded with a cool season grass, it will be completely brown before we even get the first frost of the year. Research-based information tells us to not fertilize after Aug. 1 for warm-season grasses. Fertilize much later than this, and you will be telling your grass to keep growing instead of going dormant. When the first frost comes, your grass will not be ready for it. You will likely kill a good portion of your yard!

When is the best time to fertilize? In warm-season grasses, the best time to fertilize is during or shortly after green-up. A great rule of thumb is to not fertilize before May 1. This allows the grass to green-up and get moving before we pour the coals to it! This includes weed-and-feed products. Warm-season grasses do not like weed-and-feed products, especially centipede grass. The weed component of weed-and-feed is typically a preemergent herbicide that not only prevents annual weeds from germinating, it often prevents our grasses from being able to root as well. The feed component of weed-and-feed tells our grass to grow, grow, grow! If we receive a late frost, we risk killing our grass because it is not hardened off against cold anymore.

My recipe for great grass in your yard is to use a pre-emergent herbicide suited for your type of grass in late winter to prevent germination of annual weeds. Then fertilize after May 1 on a regular schedule or according to the North Carolina State University Maintenance Calendar for your turf. Always fertilize using the recommendations from your soil report and apply herbicides according to the label. Use another pre-emergent application around mid-September to prevent winter annuals and a post-emergent application in late November to early December to take care of any late germinating winter annuals and perennials. The maintenance calendars are available online at turfiles.ces.ncsu.edu or hard copy here at the Beaufort County Extension Center. Get your calendar today to make your grass look better than your neighbor’s!

If you have a question to submit, please email to Gene Fox at gene_fox@ncsu.edu. If you’re having trouble with growing in your home landscape, call the Extension office and speak to an Extension Master Gardener volunteer, Mondays and Wednesdays, from 10 a.m. to noon, at 252-946-0111. Learn more on Facebook at the Blacklands Area Horticulture page or visit the Extension Office located at 155 Airport Road!

Gene Fox is the area consumer horticulture agent with the North Carolina Cooperative Extension.