Late September to mid-October marks a major milestone for turf landscapes in the desert. At this time, those who want to maintain green parks and lawns through the winter need to overseed Bermuda grass with winter Ryegrass.
Bermuda grass, which grows well in the summer, turns brown and goes dormant with the first frost and remains that way until spring. Ryegrass however, stays green and vibrant through the cooler months, with the exception of heavily shaded areas, and will die out with the return of triple-digit temperatures.
Steps for Overseeding Your Lawn
1. Timing is critical. The ideal time to overseed is when nighttime temperatures are regularly below 65 degrees (typically mid-October). About 2 weeks prior to overseeding, reduce the amount of irrigation water to the Bermuda by about half. This will signal the Bermuda to slow its growth and store energy for the winter.
2. In order to successfully spread the Ryegrass seed, you need to prepare the seedbed for planting. Lower the mowing height on your lawn mower in several passes, taking off about ¼ inch each mow cycle until the grass is approximately ¾ inch in height. Make sure to remove the clippings by mowing with a bag-catcher or by raking them up. The goal for this process is to make sure the Ryegrass seed comes into direct contact with the soil.
3. Now you are ready for seeding. For the best results, use perennial Ryegrass seed. Use a rotary spreader or drop spreader to evenly distribute the seed at a rate of 8 to 10 pounds per thousand square feet. To maximize germination, lightly rake and then cover the lawn with ¼ inch of mulch. Apply a starter fertilizer (6-20-20 or 6-24-24) after the seed is down. Water the area after spreading the Ryegrass seed, and set your irrigation clock to water 3 to 4 times a day at approximately 2 to 5 minute cycles. This schedule ensures the soil and mulch remain moist, and not overly wet, until germination. This step should take 7 to 10 days.
4. After the seedlings emerge, reduce watering to once daily. When the grass reaches about 2 inches in height, it is time for the first mow. Cut the grass to about 1½ inch in height and fertilize with a 21-7-14 fertilizer. Make sure to water immediately following the fertilizer application. Depending on temperatures and rainfall, you can then reduce the watering schedule to once every 2 or 3 days. To keep your lawn from turning yellow, fertilize every 3 to 6 weeks with ammonium nitrate (34-0-0) or calcium nitrate. Apply all fertilizers according to the directions on the package.
By following these steps, you should achieve a lush, green lawn through the winter months and into spring. When triple-digit temperatures return, it will be time to transition from the Ryegrass back to the Bermuda grass.