Fall Overseeding of your Warm Season Sod
Now you can use the same perennial ryegrass seed (and others!) as the pros. *Only available in AZ
When to Overseed:
Overseed established bermuda and other warm season lawns from mid-October through mid-November. Temperatures should be less than 65 F at night on a consistent basis or less than 78-83 F during the day. It is not recommended to overseed a bermuda lawn until it has been established for at least 3 months, allowing rhizomes to fully mature.
Winter Lawn Varieties
Perennial ryegrass is the primary grass for overseeding bermuda lawns. Perennial is preferred over annual ryegrass because it is heartier and the blades are darker green, finer, and easier to mow. Annual ryegrass is more likely to stain clothing and walkways.
1. You will want to rent a verticut and set it at the 1/2 to ¾ depth. Take out the thatch and dead material until you are left with approximately ½” of thatch. If you have any more than this it harbors insects, impedes water and fertilizer penetration. If you have a huge thatch buildup you have probably had some watering issues this summer and that directly impacted your drought tolerance.
2. Next you will lower your mowing height one setting and scalp down the leaf tissue. You are not trying to scalp the grass down to the dirt because this will result in a poor stand of grass for next year. You want to save some of the energy of the plant so it can come back strong in the spring. You will drop the height one more setting so you are just below your mowing height from a week ago and get a second scalp on the lawn to clean it up. This often results in the closing of the turf canopy and a second vertical cut is often necessary to open the grass plant back up. Once you have made the second vertical cut, mow up all the clippings and blow off any excess material from the grass. You lawn should have an open canopy so the seed can fall down into the thatch layer.
3. After the lawn
has been cleaned up and the yard is clear, it is time to add your starter
4. Get your perennial rye seed and have your spreader calibrated to drop 8-10 pounds of seed per 1000 SF. You will start with the perimeter of the lawn and drop the seed at a ½ rate two directions. I advise having someone follow you while you seed with some paint and mark out where the seed has fallen so you don’t overlap or miss an area. After the edges are complete you will then switch to your rotary spreader and seed the middle of the yard at ½ rate two directions. Again the total rate is 8-10 pounds per 1000 SF so you will be putting out 4-5 pounds at a time. This ensures the grass comes up in corn rows and you have not missed any areas.
5. Turn on your water for 3-4 cycles per day for 5-7 minutes. You are just trying to keep the seed moist throughout the day and free from drying out. This will be the irrigation cycle for the first two weeks until the grass has grown up to an inch. At this point you can gradually reduce some of the daily cycles and get it down to one long cycle early in the morning.
6. At the 10-14 day mark apply your second fertilizer. You should use a balanced fertilizer that will help keep the grass growing and the root system developing.
7. You may be able to mow your grass before the second fertilizer application but if not, you will do it a couple days after it has worked itself into the soil. This is a longer cut and you are just giving the grass a haircut. Ideally this cut will be made to the grass in the afternoon when it has had a chance to dry down a little.
8. At the 3-4 week mark apply your third fertilizer application. You want to do this before we receive our first frost which is generally right around Thanksgiving. This will both get your grass growing and allow the ryegrass to start to tiller and get healthy. If you wait till after the frost you will often lose color in your ryegrass and get yourself stuck behind the 8 ball.
9. You should be mowing 1-2 times per week after the lawn is established and gradually taking it to your desired mowing heights.
10. Most of you will have your lawn up and established a couple weeks before we receive a frost so it is always a good idea to get another fertilizer application down right before this happens, usually in mid November. Use a product that will sustain a good root system and also keep color once the frost hits. On our farm we switch over to Soil Burst 4-4-2 to get the grass winter hardy and maintain good color.
*** It is very important to use the right amount of seed. There are several companies that advertise that you can get 20,000 SF out of a 50 pound bag of seed. If you read the directions on the back of the bag it clearly states this is for the northern states. These labels can sometimes be confusing so be careful. Make sure you are buying a high quality perennial ryegrass seed with a minimum of 90 percent germination and zero weed seed.***
Also, check out our Sod Blog by Mr. Wise Grass for more tips here!