Green Grass in the Winter – Overseeding

front-yardGreen Grass in Winter

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.

Hand Spreader

Use a rotary spreader to distribute seed.

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.

The Benefits of Not Overseeding

The Growing Season

header_turfDoes your warm-season, hybrid Bermuda grass look sparse or weak?  The culprit may be continuous overseeding. Often times, this is due to the competition for nutrients between the Bermuda grass and the perennial Ryegrass used in fall overseeding. Overseeding leaves the Bermuda needing recovery time to build strength and vitality before the next growing season.

Overseeding in the fall does not allow Bermuda grass to complete its normal growing cycle before winter dormancy approaches. Much like a bear preparing for hibernation, Bermuda spends the weeks and months prior to the cold season storing the reserves it needs to keep its roots and stems alive through the winter. Overseeding interrupts this process and often, die-back results in the root system. The effects of interrupting this process are seen in the spring when weather conditions are right for Bermuda to begin growing again. The thick, tall Ryegrass will keep the Bermuda shaded and cool, which prolongs the dormancy period.  By keeping the Bermuda dormant longer, the percentage of Bermuda that runs out of food before it can begin to photosynthesize increases.

When the Bermuda does come out of dormancy, it must contend with the Ryegrass for nutrients while the Ryegrass is at its strongest. Ryegrass is a fierce competitor for all the resources required for Bermuda to grow: sunlight, water, nutrients and even oxygen. During early spring, the Bermuda is at a disadvantage during the time it should be strengthening to withstand the extreme heat and dryness of a typical Arizona summer. By mid-summer, the Ryegrass dies out and physically impedes the Bermuda’s ability to spread. The dead Ryegrass must be removed through dethatching, which may further injure and set back the Bermuda. In most cases, the Bermuda does not get the time needed to recover because overseeding starts again in just a few weeks.

Bermuda Comparison

We recommend suspending the overseeding process for at least one season to help restore the root system and nutrients of the Bermuda grass.

During the Dormant Months

Not overseeding turf areas with winter Ryegrass changes the focus of your seasonal practices. The steps below will help you prepare for the next season of Bermuda grass during the winter:

•  Mow twice monthly to maintain a clean appearance and
even look

•  Control weeds

•  Top dress to fill in holes and areas of compaction

What to Expect

turfBermuda grass can stay green until the first frost, usually the middle of December. Around the middle to end of March, when nighttime temperatures begin to approach 60 degrees, Bermuda starts to grow again and returns to a regular mow and care cycle.  It should also be noted that by not overseeding there are significant savings that can be helpful to any household. Click the link for an article written by a Water Conservation Specialist, highlighting some of the additional benefits.

Estimated Cost Savings