What is Overseeding, and why do it?
There are several regions throughout the United States that experience an extreme difference in temperatures, where the same type of grass doesn’t survive year-round. With extreme highs of 110+ in the summer, and lows below freezing in the winter, Phoenix is located in one of those regions. Parks and lawns in Phoenix are planted with a very durable/heat tolerant Bermuda grass base. This type of grass survives our hot Arizona summer months, but once the nighttime temperatures get into the low 70’s, Bermuda grass begins to go dormant.With that being the case… we must “overseed” this Bermuda grass base with a grass seed that will thrive during our cooler winter months.
When to Overseed
The best time to overseed is during the month of October, or when the nighttime temperatures drop into the low 70’s.
Steps for the Overseeding process
• To insure a good overseed for the winter, you need to eliminate the competition of your summer lawn and reduce the thatch that has accumulated over the summer. This is done to ensure the seed gets down to the soil.
• Process is accomplished by mowing the grass to 1” or less in height. You may have to mow your lawn 2 or 3 times to accomplish this. You are now ready to seed.
• The better quality your grass seed, the better quality your lawn will be. We recommend perennial ryegrass grasses that are suited for Arizona's desert climate, spread at a rate of 12-15 pounds per 1,000 square feet.
• Spread your seed in two directions, half in one direction and the other half in a direction perpendicular to the first. This will minimize overlaps and skips. It is important to spread your seed as evenly as possible for the best results.
• Water is critical! You want to maintain a moist seedbed for a period of seven to ten days to allow the seed to germinate. You will want to water 4 to 5 times per day for very short cycles that leave no puddles and no dry spots. After the seed has germinated and grown to a height of 3⁄4" to 1", you may reduce watering to 2-3 times per day. After ten to fourteen days, you can reduce watering to once per day. Once your winter lawn is established, you will be able to lessen the watering further.
• The first mowing should occur 14-21 days after germination. Follow the 30% rule for mowing—never remove more than 30% of the leaf at one time. This will keep you from pulling out your new young seedlings. Once your ryegrass is established, you can resume to your regular mow schedule.
Step 5—Turf Nutrition
• Your winter lawn will require a solid Turf Nutrient plan. For the best results, feed your ryegrass every 4-6 weeks with a balanced fertilizer. For an additional “kick of green”, use a fertilizer that contains iron.