The most popular method of keeping a sod grass lawn green through a Southwest winter is to over-seed with perennial ryegrass. Thanks to the beautiful dark green lawn ryegrass provides, many people feel that their winter lawns are more appealing than their summer lawns!
The optimum time to over-seed your sod grass lawn in Arizona is during the first two weeks of October, or when the evening temperatures consistently stay below 65 degrees. Although it takes a little effort, we are sure that you will love the results.
STEPS TO OVER-SEED YOUR LAWN
To insure a good over-seed 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 accomplished by scalping and de-thatching, which is the removal of leaf and thatch accumulation to ensure the seed gets down to the soil.
First, drop your mowing height down to 1⁄4″ – 1⁄2″. This should remove all of the green tissue in this process. You may have to mow your lawn 2 or 3 times to accomplish this. Collect and remove all of the clippings.
If you still have too much thatch, you may need to rent a “power rake”. This is a machine with blades that will quickly loosen and rake the thatch. Rake your lawn in 2 directions with the “power rake”, mow one more time, then collect the clippings. You should now have a lawn that is very brown, with 1⁄4′ to 1⁄2″ of stubble, a network of “runners” on the surface (above ground stolons), and just a little bit of soil showing through. You are now ready to seed.
The better quality your grass seed, the better quality your lawn will be. We recommend grasses that are suited for Arizona’s desert climate such as perennial ryegrass.
Depending on how lush you prefer your lawn and the typical grass height you are planning, the amount of seed that you will need varies:
- Home Lawns (1″-2″) — 12 pounds per 1,000 square feet
- Home Lawns ( 1⁄2″ – 1″) — 15 pounds per 1,000 square feet
- Golf course tees ( 1⁄4″) — 20 pounds per 1,000 square feet
- Golf course greens ( < 1⁄4″) — 30 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. If you overlap too much, you will have some very thick stripes in your lawn. If you have skips, you will see some very thin yellow areas in your lawn. It is important to spread your seed as evenly as possible for the best results.
Be sure to fertilize with a starter fertilizer before turning on your water. The analysis should be similar to a 6-20-20 (6% nitrogen, 20% phosphorus, 20% potassium) or 15-15-15 (15% each of nitrogen, phosphorus and potassium) mix. Follow the manufacturer’s directions on the bag for fertilizing.
This step is optional, but can be critical if you (1) do not have a good irrigation system, (2) do not have a timer that can water 4-5 times per day, or (3) the temperatures have cooled too quickly. A well-composted mulch will help retain moisture and heat necessary to germinate your perennial ryegrass. After you have spread the seed, spread the mulch 1/8″ to 1/4″ thick evenly over the whole lawn.
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 water every other day through the winter. However, when the temperatures begin to rise in the spring you may need to begin watering every night, depending on the needs of the lawn.
The first mowing should occur at the 10th to 14th day 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. Your first cut will probably be at a height of 3⁄4″ to 1″. If prefer your lawn a little longer, then you may not need to mow for 14 – 21 days. Once your ryegrass is established, you can follow normal upkeep measures outlined in our maintenance section.
Step 7—Turf Nutrition
Your winter lawn will require feeding, just like your summer lawn. Feed your ryegrass monthly with an analysis such as 21-7-14 or 22-3-9. Look for a fertilizer that contains iron or use an iron product like “Ironite” for the best results. Iron also comes in a variety of liquid products that can be sprayed on your turf. Visit your local nursery or garden center for more information.
*Be careful with iron products, they will stain concrete, cool-decking and swimming pools.