We are about to finish our field and want to seed bermudagrass on August 23, is that too late? from Raleigh, NC

Is it too late to seed bermudagrass?

We are about to finish our field and want to seed bermudagrass on August 23, is that too late? Raleigh, NC

Our new high school field will be finished in mid-August and ready for planting. Can we still plant bermudagrass sprigs or must we sod? We don’t need the field until the middle of next summer. Charlotte, NC

I have written several articles related to establishing turfgrass, but I mention the issue of timing. Establishment timing based on a date is an interesting topic because our extension publications always provide optimum situations. Our extension fact sheets indicate that in central North Carolina, the optimum planting date for bermudagrass is April to July.

Our publications do not say what will happen if someone plants after July or before April. It is logical to wonder what will happen if bermudagrass is planted in September or October. Like much in turf management, the answer is not black and white. The biggest unknown is weather, specifically the onset of cool weather and lower humidity—two situations that do not favor bermudagrass growth. The other factor that is working against you is decreasing day length.

Of course we have all experienced exceptions in weather. I remember once sprigging a bermudagrass green in Florida in late September and getting it fully grown in before the first frost. Even in Florida, that would not be a normal outcome of a late sprigging. It seems more often that weather works against you.

In the case of the fields in these questions, they are probably bare dirt at this point, so the field managers are “behind the 8-ball” in needing something on the ground before wind and rain erodes the rootzone. So they need to know their establishment options to get the ground covered one way or another.

All plants have an ideal temperature range for seed germinating and plant growth. If the temperatures are just outside the optimum, then the seed will not germinate as quickly and the resulting plant may not grow as vigorously. This is generally not a big deal. The question then becomes, is there adequate time to complete the grow-in before the first frost? But get too far outside the optimum range, and nothing may happen, no germination and no growth.

To answer the questions sent to me, the bermudagrass seed should germinate and the sprigged field should see growth. But do not expect significant turf coverage before the first frost.

It is generally recommended that soil be at least 65 degrees (optimum is 75 to 80 degrees) before planting. If the soil temperature at 1-2 inches is less than 60 degrees, do not expect germination. Sprigs should tolerate a slightly wider range of temperatures because of energy reserves in the living material. In much of North Carolina, soil temperatures are above 65 degrees in September and in many areas into October. Research reported in an Applied Turf Science paper estimated that with normal temperatures and good cultural practices, seeded bermudagrass planted as late as August 9 in Nashville, TN should have 95% coverage by October 1.

From August 9 until October 1, that is 55 days until 95% coverage. I would consider that a good grow-in rate in the transition zone. My normal response when asked how long it takes to grow-in bermudagrass (seed or sprigs) is 45 to 90 days. Under ideal conditions, with irrigation and good cultural practices, it should be on the lower end of the range. Under less than ideal conditions and no irrigation, full establishment is normally closer to the upper end of the range. Of course if you get no rain, then there is no germination or growth.

Unfortunately, seeding 14 days later (Aug 23), does not guarantee that 95% cover will be achievable by October 15. Much of the lateral growth of bermudagrass stops when the soil temperatures drop below 60 degrees. One way to cheat and extend the growing season several weeks is by using covers.

I would not normally recommend a late August planting, but if the field is bare it is probably a good risk to take, hoping for the best. Some coverage is often better than none. But be ready with a back-up plan.

Outside of using covers, my suggestion would be to have some ryegrass seed on hand to overseed if it gets late in the fall without adequate bermudagrass cover. Annual ryegrass is cheaper and seems to establish better later in the year than perennial ryegrass. But perennial ryegrass provides higher quality surface in the spring and is easier to chemically remove. In this situation, annual ryegrass usually wins. My suggestion is to keep the rate as low as practical. Less if the field will not be used until summer, more if it may get some late spring use. Between 5 to 10 pounds of seed per 1000 square feet is usually adequate.

Remember the goal is to hold the soil in place while minimizing the competition for the bermudagrass. Do not let the ryegrass grow unchecked, or you may find it shades out your bermudagrass in the spring. With some luck, you can complete your grow-in in the spring and the field will not require re-seeding or re-sprigging.