Keeping turf green in winter
In the garden, green is generally good.
Green foliage uses sunlight to make food, a process known as photosynthesis. Brown foliage means senescence, a process where nothing happens. Brown leaves, however, do not mean the plant is dead.
As winter arrives, turfgrass slowly goes to sleep. In other words, it goes dormant. The leaf blades wither and the lawn goes from green to tan. In spring, new leaves will emerge from the crown of the turfgrass plant and once again be happy and photosynthesizing.
I typically stop mowing our lawn at the end of September. Well, technically, my kids stop mowing. This way, the turf goes into winter with extra foliage to prepare for dormancy. I don’t mind the uniform tan color of our yard but, I’ve got to admit, a lush green lawn in December is quite appealing. There are a couple ways to achieve a green winter lawn.
Synthetic grass. I never thought I’d like artificial grass. I’m not recommending to sod your lawn with fake grass, but in areas where grass is impossible to grow, artificial turf is a viable option.
Deep shade, compacted soil, sloped topography and foot traffic are difficult conditions for turf.
My preference is real grass but sometimes that’s just not possible and the latest synthetic turf products are convincing.
Overseeding. The second, and preferable, option to get green winter grass is to overseed with cool-season grass such as ryegrass.
Ryegrass germinates within days and is relatively inexpensive. Both annual and perennial ryegrasses are acceptable. Perennial won’t survive our summer due to heat and humidity. There are likely some exceptions but, by and large, ryegrass fades away in summer.
Prepare to overseed your lawn about the first week of October. Be sure not to apply a pre-emergent herbicide because it will prevent the grass seed from emerging as well as weed seed.
For best success, the grass seed should make contact with the soil. Begin by mowing the lawn one inch or less and collect debris such as clippings and leaves. If the lawn is thatchy (soft and spongy), then consider dethatching it to allow seeds to make soil contact. Dethatchers can be leased from equipment rental stores.
Ryegrass should be applied at 5 to 10 pounds per 1,000 square feet with a rotary or drop spreader. If you know the square footage of your yard, you’ll be able to estimate the total pounds. For instance, if you have 3,000 square feet, you’ll need, at most, 30 pounds of seed.
To achieve uniform distribution, make the application in two directions at half rate.
For example, if you spread three pounds per 1,000 square feet on the first pass, go perpendicular on the second pass for a total of six pounds per 1,000 square feet.
Lightly irrigate a couple of times a day (as long as there is no rain) until the seedlings emerge, which, under normal circumstances, is within a week.
Once ryegrass is up, water as needed. Begin mowing when turf is 1/3 taller than the height you want to maintain. For instance, if you want to maintain lawn at 2 inches, mow when it is 3 inches tall.
While winter applications of nitrogen on dormant turf are discouraged, an overseeded lawn will benefit from monthly applications of ½ pound of nitrogen per 1,000 square feet until February to keep ryegrass lush and green.
Be prepared to encourage ryegrass to go away in March. Lower the mowing height to an inch to stress ryegrass as well as to encourage the warm-season grass to emerge from dormancy.
One last note, overseeding can be stressful on warm-season turf, in particular centipedegrass and St. Augustine due to stoloniferous growth (runners) and semi-dormant winters.
Bermudagrass and zoysia tolerate overseeding the best. Some sources even recommend skipping overseeding centipede and St. Augustine lawns every third year to allow recovery.
Whatever you choose, follow healthy maintenance practices to facilitate recovery.
Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback, email him at firstname.lastname@example.org.